Lithium–sulfur(Li–S)batteries have attracted much attention due to their ultrahigh theoretical specific capacity.However,serious capacity attenuation caused by shuttle effect still inhibits the performance improveme...Lithium–sulfur(Li–S)batteries have attracted much attention due to their ultrahigh theoretical specific capacity.However,serious capacity attenuation caused by shuttle effect still inhibits the performance improvement.Herein,a modified separator consists of the few-layer graphene as a highly conductive network and stable scaffold to support P-doped boron nitride(denoted as BN-P@GO)as the functional interlayer of Li–S batteries.The cell with the interlayer provides an initial discharge capacity as high as1045.3 mAh g^-1,and retains a high reversible capacity of 728.7 mAh g^-1 at 1 C after 500 cycles with a capacity decay of 0.061%per cycle.Moreover,the rate capability is also superior to cells with BN@GO or BN-P interlayers,i.e.reversible capcity of 457.9 mAh g^-1 even at 3 C.The excellent electrochemical performance is ascribed to the synergistic effect of physical barrier and chemical adsorption for dissolved polysulfides provided by the modified layer.Furhtermore,it also mitigates the polarization and promotes kinetic reactions of the cells.This work provides a concise and effective method for commercialization of lithium–sulfur batteries.展开更多
It is essential to manufacture microwave absorbers with strong absorption as well as tunable absorption bands at a low filler content.However,it remains challenging for pure biomass material to reach this goal without...It is essential to manufacture microwave absorbers with strong absorption as well as tunable absorption bands at a low filler content.However,it remains challenging for pure biomass material to reach this goal without loading other components.MoSe_(2),as a transition metal chalcogenide with semiconductor properties,has emerged as a potential microwave absorber filler.Herein,bacterial cellulose(BC)-derived carbon nanofibers/MoSe_(2) nanocomposite was fabricated and phosphoric acid was used to dope phosphorus in BC,in which MoSe_(2) microspheres were dropped on the BC network like a dew-covered spider web.This unique network structure enhances conductive loss and multiple reflections of the incident wave.The collocation of BC and MoSe_(2) is helpful to impedance match and introduces interfacial/dipolar polarization loss;moreover,the P-doping of BC helps to tune the absorption bands.Overall,the optimal reflection loss of undoped one reaches−53.33 dB with only 20 wt.%filler content,whose main absorption peaks focus on X-band.Interestingly,after the P-doping of BC,the main absorption peaks move to Ku-band and the optimal reflection loss gets stronger(−66.84 dB)with the same filler loading.Strong absorption and tunable absorption bands can be realized,and thus wide frequency range is covered.This work is expected to enlighten future exploration of biomass carbon materials on high-performance microwave absorption materials.展开更多
Exclusive responsiveness to ultraviolet light (~3.2 eV) and high photogenerated charge recombination rate are the two primary drawbacks of pure TiO_(2). We combined N-doped graphene quantum dots (N-GQDs), morphology r...Exclusive responsiveness to ultraviolet light (~3.2 eV) and high photogenerated charge recombination rate are the two primary drawbacks of pure TiO_(2). We combined N-doped graphene quantum dots (N-GQDs), morphology regulation, and heterojunction construction strategies to synthesize N-GQD/N-doped TiO_(2)/P-doped porous hollow g-C_(3)N_(4) nanotube (PCN) composite photocatalysts (denoted as G-TPCN). The optimal sample (G-TPCN doped with 0.1wt% N-GQD, denoted as 0.1% G-TPCN) exhibits significantly enhanced photoabsorption, which is attributed to the change in bandgap caused by elemental doping (P and N), the improved light-harvesting resulting from the tube structure, and the upconversion effect of N-GQDs. In addition, the internal charge separation and transfer capability of0.1% G-TPCN are dramatically boosted, and its carrier concentration is 3.7, 2.3, and 1.9 times that of N-TiO_(2), PCN, and N-TiO_(2)/PCN(TPCN-1), respectively. This phenomenon is attributed to the formation of Z-scheme heterojunction between N-TiO_(2) and PCNs, the excellent electron conduction ability of N-GQDs, and the short transfer distance caused by the porous nanotube structure. Compared with those of N-TiO_(2), PCNs, and TPCN-1, the H2 production activity of 0.1%G-TPCN under visible light is enhanced by 12.4, 2.3, and 1.4times, respectively, and its ciprofloxacin (CIP) degradation rate is increased by 7.9, 5.7, and 2.9 times, respectively. The optimized performance benefits from excellent photoresponsiveness and improved carrier separation and migration efficiencies. Finally, the photocatalytic mechanism of 0.1% G-TPCN and five possible degradation pathways of CIP are proposed. This study clarifies the mechanism of multiple modification strategies to synergistically improve the photocatalytic performance of 0.1% G-TPCN and provides a potential strategy for rationally designing novel photocatalysts for environmental remediation and solar energy conversion.展开更多
Silicon is a low price and high capacity ancxje material for lithium-ion batteries.The yolk-shell structure can effectively accommodate Si expansion to improve stability.However,the limited rate performance of Si anod...Silicon is a low price and high capacity ancxje material for lithium-ion batteries.The yolk-shell structure can effectively accommodate Si expansion to improve stability.However,the limited rate performance of Si anodes can't meet people's growing demand for high power density.Herein,the phosphorus-doped yolk-shell Si@C materials(P-doped Si@C)were prepared through carbon coating on P-doped Si/SiO_(x)matrix to obtain high power and stable devices.Therefore,the as-prepared P-doped Si@C electrodes delivered a rapid increase in Coulombic efficiency from 74.4%to 99.6%after only 6 cycles,high capacity retention of-95%over 800 cycles at 4 A·g^(-1),and great rate capability(510 mAh·g^(-1)at 35 A·g^(-1)).As a result,P-doped Si@C anodes paired with commercial activated carbon and LiFePO_(4)cathode to assemble lithium-ion capacitor(high power density of〜61,080 W·kg^(-1)at 20 A·g^(-1))and lithium-ion full cell(good rate performance with 68.3 mAh·g^(-1)at 5 C),respectively.This work can provide an effective way tofurther improve power density and stability for energy storage devices.展开更多
The electrochemical nitrogen reduction reaction(NRR)as an energy-efficient approach for ammonia synthesis is hampered by the low ammonia yield and ambiguous reaction mechanism.Herein,phosphorus-doped carbon nanotube(P...The electrochemical nitrogen reduction reaction(NRR)as an energy-efficient approach for ammonia synthesis is hampered by the low ammonia yield and ambiguous reaction mechanism.Herein,phosphorus-doped carbon nanotube(P-CNTs)is developed as an efficient metal-free electrocatalyst for NRR with a remarkable NH3 yield of 24.4μg·h^−1·mg^−1cat.and partial current density of 0.61 mA·cm^−2.Such superior activity is found to be from P doping and highly conjugated CNTs substrate.Experimental and theoretical investigations discover that the electron-deficient phosphorus sites with Lewis acidity should be genuine active sites and NRR on P-CNTs follows the distal pathway.These findings provide insightful understanding on NRR processes on P-CNTs,opening up opportunities for the rational design of highly-active cost-effective metal-free catalysts for electrochemical ammonia synthesis.展开更多
Self-assembled nanostructure arrays integrating the advantages of the intrinsic characters of nanostructure as well as the array stability are appealing in advanced materials.However,the precise bottom-up synthesis of...Self-assembled nanostructure arrays integrating the advantages of the intrinsic characters of nanostructure as well as the array stability are appealing in advanced materials.However,the precise bottom-up synthesis of nanostructure arrays without templates or substrates is quite challenging because of the general occurrence of homogeneous nucleation and the difficult manipulation of noncovalent interactions.Herein,we first report the precisely manipulated synthesis of well-defined louver-like P-doped carbon nitride nanowire arrays(L-PCN)via a supramolecular self-assembly method by regulating the noncovalent interactions through hydrogen bond.With this strategy,CN nanowires align in the outer frame with the separation and spatial location achieving ultrastability and outstanding photoelectricity properties.Significantly,this self-assembly L-PCN exhibits a superior visible light-driven hydrogen evolution activity of 1872.9μmol h^−1 g^−1,rendering a^25.6-fold enhancement compared to bulk CN,and high photostability.Moreover,an apparent quantum efficiency of 6.93%is achieved for hydrogen evolution at 420±15 nm.The experimental results and first-principles calculations demonstrate that the remarkable enhancement of photocatalytic activity of L-PCN can be attributed to the synergetic effect of structural topology and dopant.These findings suggest that we are able to design particular hierarchical nanostructures with desirable performance using hydrogen-bond engineering.展开更多
With practical electrocatalytic hydrogen production frequently involving the splitting of water in various pH media,there is an urgent need but still a technical challenge to develop low-cost,highly active,and stable ...With practical electrocatalytic hydrogen production frequently involving the splitting of water in various pH media,there is an urgent need but still a technical challenge to develop low-cost,highly active,and stable electrocatalysts for pH-universal hydrogen evolution reaction(HER).We report herein the adoption of a hydrothermal reaction combined with a post gas-phase doping strategy to fabricate P-doped NiCo_(2)Se_(4) hollow nanoneedle arrays on carbon fiber paper(i.e.,P-NiCo_(2)Se_(4)/CFP).Notably,the optimal arrays(P8.71-NiCo_(2)Se_(4)/CFP)can afford an outstanding pH-universal HER performance,with an overpotential as low as 33,57,and 69 mV at 10 mA·cm^(−2) and corresponding Tafel slopes down to 52,61,and 72 mV·dec^(−1) in acidic,alkaline,and neutral media,respectively,outperforming most state-of-the-art nonprecious catalysts and even the commercial Pt/C catalyst in both neutral and alkaline media at large current densities.Impressively,P_(8.71-)NiCo_(2)Se_(4)/CFP also displays good durability toward long-time stability testing in harsh acidic and alkaline electrolytes.Experimental and theoretical studies further reveal that the doping of P atoms into NiCo_(2)Se_(4) can simultaneously optimize its H*adsorption/desorption energy,water adsorption energy,and water dissociation energy by adjusting the local electronic states of various active sites,thus accelerating the rate-determining step of HER in different pH media to endow P-NiCo_(2)Se_(4) with an outstanding pH-universal HER performance.This work provides atomic-level insights into the roles of active sites in various electrolysis environments,thereby shedding new light on the rational design of highly efficient pH-universal nonprecious catalysts for HER and beyond.展开更多
g-C3N4 is a metal-free semiconductor and a potential candidate for photocatalytic H2 production,however,the drawbacks,rapid recombination rate and limited migration efficiency of photogenerated carriers,restrict its p...g-C3N4 is a metal-free semiconductor and a potential candidate for photocatalytic H2 production,however,the drawbacks,rapid recombination rate and limited migration efficiency of photogenerated carriers,restrict its photocatalytic activity.Herein,Co(II)as a hole cocatalyst modified P-doped g-C3N4 were successfully prepared to ameliorate the separation efficiency of photoinduced carriers and enhance the photocatalytic hydrogen production.The photocatalytic results demonstrated that the P-doped g-C3N4(PCN)exhibited higher photocatalytic activity compared with pure g-C3N4,while Co(II)/PCN photocatalyst exhibited further enhancement of photocatalytic performance.The proposed possible mechanism based on various characterizations is that P-doping can modulate the electronic structure of g-C3N4 to boost the separation of photogenerated-e-and h+;while the synergistic effect of both Co(II)(as hole cocatalyst)and Pt(as electron cocatalyst)can not only lead to the directional shunting of photogenerated e+-h?pairs,but further accelerate the photogenerated electrons transfer to Pt in order to join the photocatalytic reduction process for hydrogen evolution.As a result,the transportation and separation of photoinduced carriers were accelerated to greatest extent in the Pt/Co(II)/PCN photocatalyst.展开更多
Phosphorus doped（P-doped） nanogranular SiO2 films have been deposited by plasma-enhanced chemical vapor deposition. A high proton conductivity of;.2x10-4S/cm and a large electric double layer（EDL） capacitance of;....Phosphorus doped（P-doped） nanogranular SiO2 films have been deposited by plasma-enhanced chemical vapor deposition. A high proton conductivity of;.2x10-4S/cm and a large electric double layer（EDL） capacitance of;.2μF/cm2 have been obtained. Flexible coplanar-gate EDL thin film transistors（TFTs） gated by P-doped nanogranular SiO2 films are self-assembled on plastic substrates at room temperature. Due to the big EDL capacitance,such TFTs show ultra-low voltage operation of 1 V,a large field-effect mobility of 18.9 cm2/Vs,a small subthreshold swing of 85 m V/decade and a high current on/off ratio of 107. Furthermore,the EDL TFT could work in dual coplanar gate mode. AND logic operation is realized. Our results demonstrate that such TFTs gated by P-doped nanogranular SiO2 films have potential applications in low-power flexible electronics.展开更多
The phosphorus-doped single wall carbon nanotube(PSWCNT) is studied by using First-Principle methods based on Density Function Theory(DFT).The formation energy,total energy,band structure,geometry structure and densit...The phosphorus-doped single wall carbon nanotube(PSWCNT) is studied by using First-Principle methods based on Density Function Theory(DFT).The formation energy,total energy,band structure,geometry structure and density of states are calculated.It is found that the formation energy of the P-doped single carbon nanotubes increases with diameters;the total energy of carbon nanotubes with the same diameter decreases as the doping rate increases.The effects of impurity position on the impurity level are discussed.It illustrates that the position of the impurity level may depend on the C-P-C bond angle.According to the above results,it is feasible to substitute a carbon atom with a phosphorus atom in SWCNT.It is also found that P-doped carbon nanotubes are N type semiconductor.展开更多
The construction of electrode materials for lithium-ion batteries(LIBs)and sodium-ion batteries(SIBs)has gradually been an appealing and attractive technology in energy storage research field.In the present work,a fac...The construction of electrode materials for lithium-ion batteries(LIBs)and sodium-ion batteries(SIBs)has gradually been an appealing and attractive technology in energy storage research field.In the present work,a facile strategy of synthesizing ultrathin amorphous/nanocrystal dual-phase P-doped Bi_(2)MoO_(6)(denoted as P-BiMO)nanosheets via a one-step wet-chemical synthesis approach is explored.Quite distinct from conventional two-dimensional(2D)nanosheets,our newly developed ultrathin P-BiMO nanosheets exhibit a unique tunable amorphous/nanocrystalline dual-phase structure with several compelling advantages including fast ion exchange ability and superb volume change buffer capability.The experimental results reveal that our prepared P-BiMO-6 electrode delivers an excellent reversible capacity of 509.6 mA·g^(−1) after continuous 1,500 cycles at the current densities of 1,500 mA·g^(−1) and improved rate performance for LIBs.In the meanwhile,the P-BiMO-6 electrode also shows a reversible capacity of 300.6 mA·g^(−1) after 100 cycles at 50 mA·g^(−1) when being used as the SIBs electrodes.This present work uncovers an effective dual-phase nanosheet structure to improve the performance of batteries,providing an attractive paradigm to develop superior electrode materials.展开更多
Electronic structure engineering is a powerful method to tailor the behavior of adsorbed intermediates on the surface of catalysts,thus regulating catalytic activity towards CO_(2)electroreduction.Herein,we prepared a...Electronic structure engineering is a powerful method to tailor the behavior of adsorbed intermediates on the surface of catalysts,thus regulating catalytic activity towards CO_(2)electroreduction.Herein,we prepared a series of P-doped Cu catalysts for CO_(2)electroreduction into multi-carbon(C_(2+))products by regulating the surface electronic structure of Cu.The introduction of P could stabilize the surface Cu^(δ+)species,enhancing the activity for C_(2+)products via adjusting the adsorbed strength of the CO intermediates(~*CO).When the molar ratio of P to Cu was 8.3%,the catalyst exhibited a Faradaic efficiency of 64%for C_(2+)products,which was 1.9 times as high as that(33%)for Cu catalysts at the applied current density of 210 m A cm^(-2).Notably,at the applied current density of 300 mA cm^(-2),the P-doped Cu catalyst with the molar ratio of P to Cu of 8.3%exhibited the highest partial current density for C_(2+)products of 176 mA cm^(-2),whereas the partial current density for C_(2+)products over the Cu catalyst was only 84 mA cm^(-2).Mechanistic studies revealed that modulating the molar ratios of P to Cu regulated the adsorbed strength of~*CO.A moderate adsorbed strength of *CO induced by appropriate P doping was responsible for the facilitated C–C coupling process.展开更多
The growth of p-type GaAs nanowires（NWs）on GaAs（111）B substrates by metal-organic chemical vapor deposition（MOCVD）has been systematically investigated as a function of diethyl zinc（DEZn）flow.The growth rate of...The growth of p-type GaAs nanowires（NWs）on GaAs（111）B substrates by metal-organic chemical vapor deposition（MOCVD）has been systematically investigated as a function of diethyl zinc（DEZn）flow.The growth rate of GaAs NWs was slightly improved by Zn-doping and kink is observed under high DEZn flow.In addition,the Ⅰ–Ⅴ curves of GaAs NWs has been measured and the p-type dope concentration under the Ⅱ/Ⅲ ratio of 0.013 and 0.038 approximated to 1019–1020展开更多
基金the financial supports provided by the National Natural Science Foundation of China(21871164)Young Scholars Program of Shandong University(No.2017WLJH15)+2 种基金the China Postdoctoral Science Foundation(Nos.2017M610419 and 2018T110680)the Special Fund for Postdoctoral Innovation Program of Shandong Province(No.201701003)the Taishan Scholar Project of Shandong Province(No.ts201511004)
文摘Lithium–sulfur(Li–S)batteries have attracted much attention due to their ultrahigh theoretical specific capacity.However,serious capacity attenuation caused by shuttle effect still inhibits the performance improvement.Herein,a modified separator consists of the few-layer graphene as a highly conductive network and stable scaffold to support P-doped boron nitride(denoted as BN-P@GO)as the functional interlayer of Li–S batteries.The cell with the interlayer provides an initial discharge capacity as high as1045.3 mAh g^-1,and retains a high reversible capacity of 728.7 mAh g^-1 at 1 C after 500 cycles with a capacity decay of 0.061%per cycle.Moreover,the rate capability is also superior to cells with BN@GO or BN-P interlayers,i.e.reversible capcity of 457.9 mAh g^-1 even at 3 C.The excellent electrochemical performance is ascribed to the synergistic effect of physical barrier and chemical adsorption for dissolved polysulfides provided by the modified layer.Furhtermore,it also mitigates the polarization and promotes kinetic reactions of the cells.This work provides a concise and effective method for commercialization of lithium–sulfur batteries.
基金This work was supported by the National Natural Science Foundation of China(Nos.51673040 and 21978048)the Natural Science Foundation of Jiangsu Province(Nos.BK20171357 and BK20180366)+4 种基金Opening Project of Guangxi Key Laboratory of Clean Pulp&Papermaking and Pollution Control(No.GD201802-5)the Fundamental Research Funds for Central Universities(No.2242019k30042)Scientific Innovation Research Foundation of College Graduate in Jiangsu Province(No.KYCX19_0103)Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(No.1107047002)Fund Project for Transformation of Scientific and Technological Achievements of Jiangsu Province of China(No.BA2018045).
文摘It is essential to manufacture microwave absorbers with strong absorption as well as tunable absorption bands at a low filler content.However,it remains challenging for pure biomass material to reach this goal without loading other components.MoSe_(2),as a transition metal chalcogenide with semiconductor properties,has emerged as a potential microwave absorber filler.Herein,bacterial cellulose(BC)-derived carbon nanofibers/MoSe_(2) nanocomposite was fabricated and phosphoric acid was used to dope phosphorus in BC,in which MoSe_(2) microspheres were dropped on the BC network like a dew-covered spider web.This unique network structure enhances conductive loss and multiple reflections of the incident wave.The collocation of BC and MoSe_(2) is helpful to impedance match and introduces interfacial/dipolar polarization loss;moreover,the P-doping of BC helps to tune the absorption bands.Overall,the optimal reflection loss of undoped one reaches−53.33 dB with only 20 wt.%filler content,whose main absorption peaks focus on X-band.Interestingly,after the P-doping of BC,the main absorption peaks move to Ku-band and the optimal reflection loss gets stronger(−66.84 dB)with the same filler loading.Strong absorption and tunable absorption bands can be realized,and thus wide frequency range is covered.This work is expected to enlighten future exploration of biomass carbon materials on high-performance microwave absorption materials.
基金financially supported by the National Natural Science Foundation of China (Nos.U2002212,52102058,52204414,52204413,and 52204412)the National Key R&D Program of China (Nos.2021YFC1910504,2019YFC1907101,2019YFC1907103,and 2017YFB0702304)+7 种基金the Key R&D Program of Ningxia Hui Autonomous Region,China (Nos.2021BEG01003 and2020BCE01001)the Xijiang Innovation and Entrepreneurship Team,China (No.2017A0109004)the Macao Young Scholars Program (No.AM2022024),Chinathe Beijing Natural Science Foundation (Nos.L212020 and 2214073),Chinathe Guangdong Basic and Applied Basic Research Foundation,China (Nos.2021A1515110998 and 2020A1515110408)the China Postdoctoral Science Foundation (No.2022M710349)the Fundamental Research Funds for the Central Universities,China (Nos.FRF-BD-20-24A,FRF-TP-20-031A1,FRF-IC-19-017Z,and 06500141)the Integration of Green Key Process Systems MIIT and Scientific and Technological Innovation Foundation of Foshan,China(Nos.BK22BE001 and BK21BE002)。
文摘Exclusive responsiveness to ultraviolet light (~3.2 eV) and high photogenerated charge recombination rate are the two primary drawbacks of pure TiO_(2). We combined N-doped graphene quantum dots (N-GQDs), morphology regulation, and heterojunction construction strategies to synthesize N-GQD/N-doped TiO_(2)/P-doped porous hollow g-C_(3)N_(4) nanotube (PCN) composite photocatalysts (denoted as G-TPCN). The optimal sample (G-TPCN doped with 0.1wt% N-GQD, denoted as 0.1% G-TPCN) exhibits significantly enhanced photoabsorption, which is attributed to the change in bandgap caused by elemental doping (P and N), the improved light-harvesting resulting from the tube structure, and the upconversion effect of N-GQDs. In addition, the internal charge separation and transfer capability of0.1% G-TPCN are dramatically boosted, and its carrier concentration is 3.7, 2.3, and 1.9 times that of N-TiO_(2), PCN, and N-TiO_(2)/PCN(TPCN-1), respectively. This phenomenon is attributed to the formation of Z-scheme heterojunction between N-TiO_(2) and PCNs, the excellent electron conduction ability of N-GQDs, and the short transfer distance caused by the porous nanotube structure. Compared with those of N-TiO_(2), PCNs, and TPCN-1, the H2 production activity of 0.1%G-TPCN under visible light is enhanced by 12.4, 2.3, and 1.4times, respectively, and its ciprofloxacin (CIP) degradation rate is increased by 7.9, 5.7, and 2.9 times, respectively. The optimized performance benefits from excellent photoresponsiveness and improved carrier separation and migration efficiencies. Finally, the photocatalytic mechanism of 0.1% G-TPCN and five possible degradation pathways of CIP are proposed. This study clarifies the mechanism of multiple modification strategies to synergistically improve the photocatalytic performance of 0.1% G-TPCN and provides a potential strategy for rationally designing novel photocatalysts for environmental remediation and solar energy conversion.
基金Science and Technology Commission of Shanghai Municipality(Nos.20520710400,18230743400,18QA1402400)the National Natural Science Foundation of China(No.21771124)+1 种基金Oceanic Interdisciplinary Program of Shanghai Jiao Tong University(No.SL2020MS020)SJTU-Warwick Joint Seed Fund(2019/20).
文摘Silicon is a low price and high capacity ancxje material for lithium-ion batteries.The yolk-shell structure can effectively accommodate Si expansion to improve stability.However,the limited rate performance of Si anodes can't meet people's growing demand for high power density.Herein,the phosphorus-doped yolk-shell Si@C materials(P-doped Si@C)were prepared through carbon coating on P-doped Si/SiO_(x)matrix to obtain high power and stable devices.Therefore,the as-prepared P-doped Si@C electrodes delivered a rapid increase in Coulombic efficiency from 74.4%to 99.6%after only 6 cycles,high capacity retention of-95%over 800 cycles at 4 A·g^(-1),and great rate capability(510 mAh·g^(-1)at 35 A·g^(-1)).As a result,P-doped Si@C anodes paired with commercial activated carbon and LiFePO_(4)cathode to assemble lithium-ion capacitor(high power density of〜61,080 W·kg^(-1)at 20 A·g^(-1))and lithium-ion full cell(good rate performance with 68.3 mAh·g^(-1)at 5 C),respectively.This work can provide an effective way tofurther improve power density and stability for energy storage devices.
基金We acknowledge the financial supports are from the National Key Research and Development Program of China(No.2016YFB0101202)the National Natural Science Foundation of China(Nos.91645123,21773263).
文摘The electrochemical nitrogen reduction reaction(NRR)as an energy-efficient approach for ammonia synthesis is hampered by the low ammonia yield and ambiguous reaction mechanism.Herein,phosphorus-doped carbon nanotube(P-CNTs)is developed as an efficient metal-free electrocatalyst for NRR with a remarkable NH3 yield of 24.4μg·h^−1·mg^−1cat.and partial current density of 0.61 mA·cm^−2.Such superior activity is found to be from P doping and highly conjugated CNTs substrate.Experimental and theoretical investigations discover that the electron-deficient phosphorus sites with Lewis acidity should be genuine active sites and NRR on P-CNTs follows the distal pathway.These findings provide insightful understanding on NRR processes on P-CNTs,opening up opportunities for the rational design of highly-active cost-effective metal-free catalysts for electrochemical ammonia synthesis.
基金the National Natural Science Foundation of China(Nos.51772085 and U1830138)Hunan Provincial Innovation Foundation for Postgraduate(No.CX20190311)
文摘Self-assembled nanostructure arrays integrating the advantages of the intrinsic characters of nanostructure as well as the array stability are appealing in advanced materials.However,the precise bottom-up synthesis of nanostructure arrays without templates or substrates is quite challenging because of the general occurrence of homogeneous nucleation and the difficult manipulation of noncovalent interactions.Herein,we first report the precisely manipulated synthesis of well-defined louver-like P-doped carbon nitride nanowire arrays(L-PCN)via a supramolecular self-assembly method by regulating the noncovalent interactions through hydrogen bond.With this strategy,CN nanowires align in the outer frame with the separation and spatial location achieving ultrastability and outstanding photoelectricity properties.Significantly,this self-assembly L-PCN exhibits a superior visible light-driven hydrogen evolution activity of 1872.9μmol h^−1 g^−1,rendering a^25.6-fold enhancement compared to bulk CN,and high photostability.Moreover,an apparent quantum efficiency of 6.93%is achieved for hydrogen evolution at 420±15 nm.The experimental results and first-principles calculations demonstrate that the remarkable enhancement of photocatalytic activity of L-PCN can be attributed to the synergetic effect of structural topology and dopant.These findings suggest that we are able to design particular hierarchical nanostructures with desirable performance using hydrogen-bond engineering.
基金supported by the National Natural Science Foundation of China(Nos.21872011 and 21273020).
文摘With practical electrocatalytic hydrogen production frequently involving the splitting of water in various pH media,there is an urgent need but still a technical challenge to develop low-cost,highly active,and stable electrocatalysts for pH-universal hydrogen evolution reaction(HER).We report herein the adoption of a hydrothermal reaction combined with a post gas-phase doping strategy to fabricate P-doped NiCo_(2)Se_(4) hollow nanoneedle arrays on carbon fiber paper(i.e.,P-NiCo_(2)Se_(4)/CFP).Notably,the optimal arrays(P8.71-NiCo_(2)Se_(4)/CFP)can afford an outstanding pH-universal HER performance,with an overpotential as low as 33,57,and 69 mV at 10 mA·cm^(−2) and corresponding Tafel slopes down to 52,61,and 72 mV·dec^(−1) in acidic,alkaline,and neutral media,respectively,outperforming most state-of-the-art nonprecious catalysts and even the commercial Pt/C catalyst in both neutral and alkaline media at large current densities.Impressively,P_(8.71-)NiCo_(2)Se_(4)/CFP also displays good durability toward long-time stability testing in harsh acidic and alkaline electrolytes.Experimental and theoretical studies further reveal that the doping of P atoms into NiCo_(2)Se_(4) can simultaneously optimize its H*adsorption/desorption energy,water adsorption energy,and water dissociation energy by adjusting the local electronic states of various active sites,thus accelerating the rate-determining step of HER in different pH media to endow P-NiCo_(2)Se_(4) with an outstanding pH-universal HER performance.This work provides atomic-level insights into the roles of active sites in various electrolysis environments,thereby shedding new light on the rational design of highly efficient pH-universal nonprecious catalysts for HER and beyond.
基金supported by the National Natural Science Foundation of China(51672113)QingLan Project Foundation of Jiangsu Province(201611)~~
文摘g-C3N4 is a metal-free semiconductor and a potential candidate for photocatalytic H2 production,however,the drawbacks,rapid recombination rate and limited migration efficiency of photogenerated carriers,restrict its photocatalytic activity.Herein,Co(II)as a hole cocatalyst modified P-doped g-C3N4 were successfully prepared to ameliorate the separation efficiency of photoinduced carriers and enhance the photocatalytic hydrogen production.The photocatalytic results demonstrated that the P-doped g-C3N4(PCN)exhibited higher photocatalytic activity compared with pure g-C3N4,while Co(II)/PCN photocatalyst exhibited further enhancement of photocatalytic performance.The proposed possible mechanism based on various characterizations is that P-doping can modulate the electronic structure of g-C3N4 to boost the separation of photogenerated-e-and h+;while the synergistic effect of both Co(II)(as hole cocatalyst)and Pt(as electron cocatalyst)can not only lead to the directional shunting of photogenerated e+-h?pairs,but further accelerate the photogenerated electrons transfer to Pt in order to join the photocatalytic reduction process for hydrogen evolution.As a result,the transportation and separation of photoinduced carriers were accelerated to greatest extent in the Pt/Co(II)/PCN photocatalyst.
基金supported by the National Natural Science Foundation of China (Grant No.51302276)the Zhejiang Provincial Natural Science Foundation of China (Grant No.LY14A040009)in part by the Foundation of the Science and Technology Bureau of Wuhan City (Grant No.2014010101010006)
文摘Phosphorus doped（P-doped） nanogranular SiO2 films have been deposited by plasma-enhanced chemical vapor deposition. A high proton conductivity of;.2x10-4S/cm and a large electric double layer（EDL） capacitance of;.2μF/cm2 have been obtained. Flexible coplanar-gate EDL thin film transistors（TFTs） gated by P-doped nanogranular SiO2 films are self-assembled on plastic substrates at room temperature. Due to the big EDL capacitance,such TFTs show ultra-low voltage operation of 1 V,a large field-effect mobility of 18.9 cm2/Vs,a small subthreshold swing of 85 m V/decade and a high current on/off ratio of 107. Furthermore,the EDL TFT could work in dual coplanar gate mode. AND logic operation is realized. Our results demonstrate that such TFTs gated by P-doped nanogranular SiO2 films have potential applications in low-power flexible electronics.
基金Supported by the Natural Science Foundation of Fujian Province of China (Grant No. A0220001)
文摘The phosphorus-doped single wall carbon nanotube(PSWCNT) is studied by using First-Principle methods based on Density Function Theory(DFT).The formation energy,total energy,band structure,geometry structure and density of states are calculated.It is found that the formation energy of the P-doped single carbon nanotubes increases with diameters;the total energy of carbon nanotubes with the same diameter decreases as the doping rate increases.The effects of impurity position on the impurity level are discussed.It illustrates that the position of the impurity level may depend on the C-P-C bond angle.According to the above results,it is feasible to substitute a carbon atom with a phosphorus atom in SWCNT.It is also found that P-doped carbon nanotubes are N type semiconductor.
基金supported by Shenzhen-Hong Kong Science and Technology Innovation Cooperation Zone Shenzhen Park Project:HZQB-KCZYB-2020030the National Key R&D Program of China(Project No.2017YFA0204403)Hong Kong Innovation and Technology Commission via the Hong Kong Branch of National Precious Metals Material Engineering Research Center.
文摘The construction of electrode materials for lithium-ion batteries(LIBs)and sodium-ion batteries(SIBs)has gradually been an appealing and attractive technology in energy storage research field.In the present work,a facile strategy of synthesizing ultrathin amorphous/nanocrystal dual-phase P-doped Bi_(2)MoO_(6)(denoted as P-BiMO)nanosheets via a one-step wet-chemical synthesis approach is explored.Quite distinct from conventional two-dimensional(2D)nanosheets,our newly developed ultrathin P-BiMO nanosheets exhibit a unique tunable amorphous/nanocrystalline dual-phase structure with several compelling advantages including fast ion exchange ability and superb volume change buffer capability.The experimental results reveal that our prepared P-BiMO-6 electrode delivers an excellent reversible capacity of 509.6 mA·g^(−1) after continuous 1,500 cycles at the current densities of 1,500 mA·g^(−1) and improved rate performance for LIBs.In the meanwhile,the P-BiMO-6 electrode also shows a reversible capacity of 300.6 mA·g^(−1) after 100 cycles at 50 mA·g^(−1) when being used as the SIBs electrodes.This present work uncovers an effective dual-phase nanosheet structure to improve the performance of batteries,providing an attractive paradigm to develop superior electrode materials.
基金supported by National Science Fund for Distinguished Young Scholars(21925204)the National Natural Science Foundation of China(U1932146,U19A2015,21673214,and U1732272)+3 种基金National Key Research and Development Program of China(2019YFA0405600,2017YFA0403402,and 2019YFA0405602)Key Research Program of Frontier Sciences of the CAS(QYZDB-SSW-SLH017)Fundamental Research Funds for the Central UniversitiesUSTC Research Funds of the Double First-Class Initiative(YD2340002002)。
文摘Electronic structure engineering is a powerful method to tailor the behavior of adsorbed intermediates on the surface of catalysts,thus regulating catalytic activity towards CO_(2)electroreduction.Herein,we prepared a series of P-doped Cu catalysts for CO_(2)electroreduction into multi-carbon(C_(2+))products by regulating the surface electronic structure of Cu.The introduction of P could stabilize the surface Cu^(δ+)species,enhancing the activity for C_(2+)products via adjusting the adsorbed strength of the CO intermediates(~*CO).When the molar ratio of P to Cu was 8.3%,the catalyst exhibited a Faradaic efficiency of 64%for C_(2+)products,which was 1.9 times as high as that(33%)for Cu catalysts at the applied current density of 210 m A cm^(-2).Notably,at the applied current density of 300 mA cm^(-2),the P-doped Cu catalyst with the molar ratio of P to Cu of 8.3%exhibited the highest partial current density for C_(2+)products of 176 mA cm^(-2),whereas the partial current density for C_(2+)products over the Cu catalyst was only 84 mA cm^(-2).Mechanistic studies revealed that modulating the molar ratios of P to Cu regulated the adsorbed strength of~*CO.A moderate adsorbed strength of *CO induced by appropriate P doping was responsible for the facilitated C–C coupling process.
基金Project supported by the National Natural Science Foundation of China(Nos.61376019,61504010,61774021)the Fund of State Key Laboratory of Information Photonics and Optical Communications(Beijing University of Posts and Telecommunications),China(Nos.IPOC2017ZT02,IPOC2017ZZ01)
文摘The growth of p-type GaAs nanowires（NWs）on GaAs（111）B substrates by metal-organic chemical vapor deposition（MOCVD）has been systematically investigated as a function of diethyl zinc（DEZn）flow.The growth rate of GaAs NWs was slightly improved by Zn-doping and kink is observed under high DEZn flow.In addition,the Ⅰ–Ⅴ curves of GaAs NWs has been measured and the p-type dope concentration under the Ⅱ/Ⅲ ratio of 0.013 and 0.038 approximated to 1019–1020
