Two-dimensional mesoporous ultrathin Cd0.5Zn0.5S nanosheets with a thickness of~1.5 nm were fabricated using a multistep chemical transformation strategy involving inorganic–organic hybrid ZnS-ethylenediamine(denoted...Two-dimensional mesoporous ultrathin Cd0.5Zn0.5S nanosheets with a thickness of~1.5 nm were fabricated using a multistep chemical transformation strategy involving inorganic–organic hybrid ZnS-ethylenediamine(denoted as ZnS(en)0.5)as a hard template.Inorganic–organic hybrid ZnS(en)0.5,Cd0.5Zn0.5S(en)x,and Cd0.5Zn0.5S nanosheets were sequentially fabricated,and their transformation processes were analyzed in detail.The fabricated Cd0.5Zn0.5S nanosheets exhibited high photocatalytic hydrogen evolution reaction activity in the presence of a sacrificial agent.The Cd0.5Zn0.5S nanosheets exhibited remarkably high H2 production activity of~1395μmol∙h^−1∙g^−1 in pure water with no co-catalyst,which is the highest value reported thus far for bare photocatalysts,to the best of our knowledge.The high activity of these nanosheets is attributed to their distinct nanostructure(e.g.,short transfer distance of photoinduced charge carriers,large number of unsaturated surface atoms,and large surface area).Moreover,ternary NiCo2S4 nanoparticles were employed to facilitate the charge separation and enhance the surface kinetics of H2 evolution.The H2 production rate reached~62.2 and~2436μmol∙h^−1∙g^−1 in triethanolamine and pure water,respectively,over the NiCo2S4/Cd0.5Zn0.5S heterojunctions.The result indicated that the Schottky junction was critical to the enhanced activity.The proposed method can be used for fabricating other highly efficient CdZnS-based photocatalysts for solar-energy conversion or other applications.展开更多
Cd_(0.5)Zn_(0.5)S/g-C_(3)N_(4)(CZS/CN)step-like heterojunction composites were facilely synthesized by annealing a sandwich of cadmium-zinc-thiourea precursors in one pot.The types of the used raw materials and the pr...Cd_(0.5)Zn_(0.5)S/g-C_(3)N_(4)(CZS/CN)step-like heterojunction composites were facilely synthesized by annealing a sandwich of cadmium-zinc-thiourea precursors in one pot.The types of the used raw materials and the preparation procedure were simplified as much as possible in this work.The obtained hybrid exhibited enlarged specific surface area and higher separation/transfer efficiency of charge carriers compared to pure Cd_(0.5)Zn_(0.5)S and g–C_(3)N_(4),thus exhibited much enhanced photocatalytic efficiency for dye degradation under visible-light irradiation.The interfacial charge-transfer mechanism of the formed step-scheme(Sscheme)heterojunction between Cd_(0.5)Zn_(0.5)S and g–C_(3)N_(4) were carefully investigated and discussed.This work could widen the application prospect of the Cd_(x)Zn_(1-x)S/g-C_(3)N_(4) composite and provide new ideas to the design and fabrication of novel heterojunctions with robust photocatalytic performance.展开更多
In this work,a novel plasmon-assisted UV-vis-NIR-driven W_(18)O_(49)/Cd_(0.5)Zn_(0.5)S heterostructure photocatalyst was obtained by a facile ultrasonic-assisted electrostatic self-assembly strategy.The hybrid exhibit...In this work,a novel plasmon-assisted UV-vis-NIR-driven W_(18)O_(49)/Cd_(0.5)Zn_(0.5)S heterostructure photocatalyst was obtained by a facile ultrasonic-assisted electrostatic self-assembly strategy.The hybrid exhibits extraordinary H2 evolution activity of 147.7 mmol·g^(-1)·h^(-1) at room temperature due to the efficient charge separation and expanded light absorption.Our investigation shows that the unique Step-scheme(S-scheme)charge transfer and the‘hot electron’injection are both responsible for the extraordinary H2 evolution process,depending on the wavelength of the incident light.Moreover,by accelerating the surface reaction kinetics,the activity can be further elevated to 306.1 mmol·g^(-1)·h^(-1),accompanied by a high apparent quantum yield of 45.3% at 365±7.5 nm.This work provides us a potential strategy for the highly efficient conversion of the solar energy by elaborately combining a nonstoichiometric ratio plasmonic material with an appropriate active photocatalyst.展开更多
Solar-driven CO_(2)conversion to chemical fuels in an aqueous solution is restricted not only by photocatalysts but also by mass transfer.Here,a regulatable three-phase interface on a porous fixed-bed is constructed f...Solar-driven CO_(2)conversion to chemical fuels in an aqueous solution is restricted not only by photocatalysts but also by mass transfer.Here,a regulatable three-phase interface on a porous fixed-bed is constructed for efficient C-C coupling in photocatalytic CO_(2)reduction.The photocatalytic results show that∼90%selectivity towards C^(2+)products is obtained by a Cu/Cd_(0.5)Zn_(0.5)S photocatalyst,with a yield of 6.54μmol/h(an irradiation area of 0.785 cm^(2)),while only 0.94μmol/h(an irradiation area of 19.625 cm^(2))is achieved with a commonly used suspension photocatalytic reactor.We find that under the same CO_(2)feed rate,the local CO_(2)concentration in this porous fixed-bed photoreactor is obviously higher than in the suspension photoreactor.The larger local CO_(2)coverage derived from a higher CO_(2)supply and aggregation enhances the C-C coupling,thereby generating more C^(2+).Even an observable three-phase interface on the porous fixed-bed can be regulated by adjusting the CO_(2)supply,for which the optimal gas inlet rate is 5-10 sccm.展开更多
The development of highly efficient catalyst is the key for photocatalytic technology to deal with water pollution and energy problems.In this work,the S-scheme polyaniline/Cd_(0.5)Zn_(0.5)S(PANI/CZS)nanocomposites we...The development of highly efficient catalyst is the key for photocatalytic technology to deal with water pollution and energy problems.In this work,the S-scheme polyaniline/Cd_(0.5)Zn_(0.5)S(PANI/CZS)nanocomposites were elaborately prepared for the first time by in-situ oxidation polymerization.Compared to pure PANI and Cd_(0.5)Zn_(0.5)S,this PANI/CZS hybrid displayed outstanding photocatalytic performance in removing tetracycline hydrochloride(TCH)and hydrogen evolution under light irradiation.Among them,15 PANI/CZS sample could achieve 84.9%TCH degradation efficiency within 25 min,and the degradation rate(0.06931 min−1)was 5.13 times than that of Cd_(0.5)Zn_(0.5)S(0.0135 min^(−1)).The optimal photocatalytic H_(2) evolution rate of 30 PANI/CZS sample was 15.57 mmol g^(-1) h^(-1),which was twice that of Cd_(0.5)Zn_(0.5)S(7.34 mmol g^(-1) h^(-1)).These results were mainly attributed to the efficient electronic transport channels provided by S-scheme heterojunction structure.The density functional theory(DFT)calculation proved that the difference of work function resulted in band bending and forming built-in electric field on the contact interface of PANI/CZS,which facilitated the migration and separation of interfacial photogener-ated charge carriers for the strengthened photocatalytic performance.Further,the degradation interme-diate products and pathways of TCH were also put forwarded in depth based on MS experiment.At last,the S-scheme electron transport model and the photocatalytic reaction mechanism in PANI/CZS hetero-junction structure were studied.This work provided an innovative vision in developing high-performance S-scheme heterojunction multifunctional photocatalysts.展开更多
Converting water into hydrogen fuel and oxidizing benzyl alcohol to benzaldehyde simultaneously under visible light illumination is of great significance,but the fast recombination of photogenerated carriers in photoc...Converting water into hydrogen fuel and oxidizing benzyl alcohol to benzaldehyde simultaneously under visible light illumination is of great significance,but the fast recombination of photogenerated carriers in photocatalysts seriously decreases the conversion efficiency.Herein,a novel dual-functional 0D Cd_(0.5)Zn_(0.5)S/2D Ti_(3)C2 hybrid was fabricated by a solvothermally in-situ generated assembling method.The Cd_(0.5)Zn_(0.5)S nano-spheres with a fluffy surface completely and uniformly covered the ultrathin Ti_(3)C2 nanosheets,leading to the increased Schottky barrier(SB)sites due to a large contact area,which could accelerate the electron–hole separation and improve the light utilization.The optimized Cd_(0.5)Zn_(0.5)S/Ti_(3)C2 hybrid simultaneously presents a hydrogen evolution rate of 5.3 mmol/(g·h)and a benzaldehyde production rate of 29.3 mmol/(g·h),which are~3.2 and 2 times higher than those of pristine Cd_(0.5)Zn_(0.5)S,respectively.Both the multiple experimental measurements and the density functional theory(DFT)calculations further demonstrate the tight connection between Cd_(0.5)Zn_(0.5)S and Ti_(3)C2,formation of Schottky junction,and efficient photogenerated electron–hole separation.This paper suggests a dual-functional composite catalyst for photocatalytic hydrogen evolution and benzaldehyde production,and provides a new strategy for preventing the photogenerated electrons and holes from recombining by constructing a 0D/2D heterojunction with increased SB sites.展开更多
Photocatalytic water splitting for hydrogen(H_(2))production is a green sustainable technology,in which highly-efficient steady photocatalysts are fundamentally required.In this work,unique CdS/Cd_(0.5)Zn_(0.5)S-M0_(1...Photocatalytic water splitting for hydrogen(H_(2))production is a green sustainable technology,in which highly-efficient steady photocatalysts are fundamentally required.In this work,unique CdS/Cd_(0.5)Zn_(0.5)S-M0_(1-x)W_(x)S_(2) photocatalyst constructed by CdS hollow nano-spheres with successively surface-modified Cd_(0.5)Zn_(0.5)S shell and defect-rich MO_(1-x)W_(x)S_(2) ultrathin nanosheets was reported for the first time.Interestingly,the Cd_(0.5)Zn_(0.5)S shell could greatly enhance the photo-stability and reduce the carrier recombination of CdS.Meanwhile,enriching active sites and accelerating charge transfer could be achieved via anchoring defect-rich Mo_(1-x)W_(x)S_(2) onto CdS/Cd_(0.5)Zn_(0.5)S hollow heterostructures.Specifically,the optimized CdS/Cd_(0.5)Zn_(0.5)S-Mo_(1-x)W_(x)Sa(6 h Cd_(0.5)Zn_(0.5)S-coating,7 wt.%Mo_(1-x)W_(x)S_(2),x=0.5)hybrid delivered an exceptional H_(2) generation rate of 215.99 mmol·g^(-1)·h^(-1),which is approximately 502,134,and 23 times that of pure CdS,CdS/Cd_(0.5)Zn_(0.5)S,and 3 wt.%Pt-loaded CdS/Cd_(0.5)Zn_(0.5)S,respectively.Remarkably,a high H_(2) evolution reaction(HER)apparent quantum yield(AQY)of 64.81%was obtained under 420-nm irradiation.In addition,the CdS/Cd_(0.5)Zn_(0.5)S-Mo_(1-x)W_(x)S_(2) was also durable for H2 production under long-term irradiation.This work provides valuable inspirations to rational design and synthesis of efficient and stable hybrid photocatalysts for solar energy conversion.展开更多
文摘Two-dimensional mesoporous ultrathin Cd0.5Zn0.5S nanosheets with a thickness of~1.5 nm were fabricated using a multistep chemical transformation strategy involving inorganic–organic hybrid ZnS-ethylenediamine(denoted as ZnS(en)0.5)as a hard template.Inorganic–organic hybrid ZnS(en)0.5,Cd0.5Zn0.5S(en)x,and Cd0.5Zn0.5S nanosheets were sequentially fabricated,and their transformation processes were analyzed in detail.The fabricated Cd0.5Zn0.5S nanosheets exhibited high photocatalytic hydrogen evolution reaction activity in the presence of a sacrificial agent.The Cd0.5Zn0.5S nanosheets exhibited remarkably high H2 production activity of~1395μmol∙h^−1∙g^−1 in pure water with no co-catalyst,which is the highest value reported thus far for bare photocatalysts,to the best of our knowledge.The high activity of these nanosheets is attributed to their distinct nanostructure(e.g.,short transfer distance of photoinduced charge carriers,large number of unsaturated surface atoms,and large surface area).Moreover,ternary NiCo2S4 nanoparticles were employed to facilitate the charge separation and enhance the surface kinetics of H2 evolution.The H2 production rate reached~62.2 and~2436μmol∙h^−1∙g^−1 in triethanolamine and pure water,respectively,over the NiCo2S4/Cd0.5Zn0.5S heterojunctions.The result indicated that the Schottky junction was critical to the enhanced activity.The proposed method can be used for fabricating other highly efficient CdZnS-based photocatalysts for solar-energy conversion or other applications.
基金financially supported by the National Natural Science Foundation of China(Nos.21972171 and 51672312)the Fundamental Research Funds for the Central Universities,South Central University for Nationalities(No.CZT20016)。
文摘Cd_(0.5)Zn_(0.5)S/g-C_(3)N_(4)(CZS/CN)step-like heterojunction composites were facilely synthesized by annealing a sandwich of cadmium-zinc-thiourea precursors in one pot.The types of the used raw materials and the preparation procedure were simplified as much as possible in this work.The obtained hybrid exhibited enlarged specific surface area and higher separation/transfer efficiency of charge carriers compared to pure Cd_(0.5)Zn_(0.5)S and g–C_(3)N_(4),thus exhibited much enhanced photocatalytic efficiency for dye degradation under visible-light irradiation.The interfacial charge-transfer mechanism of the formed step-scheme(Sscheme)heterojunction between Cd_(0.5)Zn_(0.5)S and g–C_(3)N_(4) were carefully investigated and discussed.This work could widen the application prospect of the Cd_(x)Zn_(1-x)S/g-C_(3)N_(4) composite and provide new ideas to the design and fabrication of novel heterojunctions with robust photocatalytic performance.
文摘In this work,a novel plasmon-assisted UV-vis-NIR-driven W_(18)O_(49)/Cd_(0.5)Zn_(0.5)S heterostructure photocatalyst was obtained by a facile ultrasonic-assisted electrostatic self-assembly strategy.The hybrid exhibits extraordinary H2 evolution activity of 147.7 mmol·g^(-1)·h^(-1) at room temperature due to the efficient charge separation and expanded light absorption.Our investigation shows that the unique Step-scheme(S-scheme)charge transfer and the‘hot electron’injection are both responsible for the extraordinary H2 evolution process,depending on the wavelength of the incident light.Moreover,by accelerating the surface reaction kinetics,the activity can be further elevated to 306.1 mmol·g^(-1)·h^(-1),accompanied by a high apparent quantum yield of 45.3% at 365±7.5 nm.This work provides us a potential strategy for the highly efficient conversion of the solar energy by elaborately combining a nonstoichiometric ratio plasmonic material with an appropriate active photocatalyst.
基金S.J.Bai,H.R.Qiu,and M.M.Song contributed equally to this work.This work is supported by the Basic Science Center Program for Ordered Energy Conversion of the National Natural Science Foundation of China(No.51888103).We also thank C.Liao for drawing some pictures for this article.In addition,we thank Doc.N.Deng and Miss D.He at the Instrumental Analysis Center of Xi'an Jiaotong University for their assistance with GC-MS and TRPL measurement.
文摘Solar-driven CO_(2)conversion to chemical fuels in an aqueous solution is restricted not only by photocatalysts but also by mass transfer.Here,a regulatable three-phase interface on a porous fixed-bed is constructed for efficient C-C coupling in photocatalytic CO_(2)reduction.The photocatalytic results show that∼90%selectivity towards C^(2+)products is obtained by a Cu/Cd_(0.5)Zn_(0.5)S photocatalyst,with a yield of 6.54μmol/h(an irradiation area of 0.785 cm^(2)),while only 0.94μmol/h(an irradiation area of 19.625 cm^(2))is achieved with a commonly used suspension photocatalytic reactor.We find that under the same CO_(2)feed rate,the local CO_(2)concentration in this porous fixed-bed photoreactor is obviously higher than in the suspension photoreactor.The larger local CO_(2)coverage derived from a higher CO_(2)supply and aggregation enhances the C-C coupling,thereby generating more C^(2+).Even an observable three-phase interface on the porous fixed-bed can be regulated by adjusting the CO_(2)supply,for which the optimal gas inlet rate is 5-10 sccm.
基金supported by National Natural Science Foundation of China (Nos.21777062,22178151 and 51872128)National&Local Joint Engineering Research Center for Mineral Salt Deep Utilization of Huaiyin Institute of Technology (Nos.SF202008,SF202204 and SF202106)Guangdong Basic and Applied Basic Research Foundation (No.2021A1515111231).
文摘The development of highly efficient catalyst is the key for photocatalytic technology to deal with water pollution and energy problems.In this work,the S-scheme polyaniline/Cd_(0.5)Zn_(0.5)S(PANI/CZS)nanocomposites were elaborately prepared for the first time by in-situ oxidation polymerization.Compared to pure PANI and Cd_(0.5)Zn_(0.5)S,this PANI/CZS hybrid displayed outstanding photocatalytic performance in removing tetracycline hydrochloride(TCH)and hydrogen evolution under light irradiation.Among them,15 PANI/CZS sample could achieve 84.9%TCH degradation efficiency within 25 min,and the degradation rate(0.06931 min−1)was 5.13 times than that of Cd_(0.5)Zn_(0.5)S(0.0135 min^(−1)).The optimal photocatalytic H_(2) evolution rate of 30 PANI/CZS sample was 15.57 mmol g^(-1) h^(-1),which was twice that of Cd_(0.5)Zn_(0.5)S(7.34 mmol g^(-1) h^(-1)).These results were mainly attributed to the efficient electronic transport channels provided by S-scheme heterojunction structure.The density functional theory(DFT)calculation proved that the difference of work function resulted in band bending and forming built-in electric field on the contact interface of PANI/CZS,which facilitated the migration and separation of interfacial photogener-ated charge carriers for the strengthened photocatalytic performance.Further,the degradation interme-diate products and pathways of TCH were also put forwarded in depth based on MS experiment.At last,the S-scheme electron transport model and the photocatalytic reaction mechanism in PANI/CZS hetero-junction structure were studied.This work provided an innovative vision in developing high-performance S-scheme heterojunction multifunctional photocatalysts.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.51902137 and 51672113)the Key Research and Development Plan(Grant No.BE2019094)+1 种基金the Qing Lan Project([2016]15)of Jiangsu ProvinceThe calculations were carried out by the Advanced Computing East China Sub-center and Big Data Center of Southeast University。
文摘Converting water into hydrogen fuel and oxidizing benzyl alcohol to benzaldehyde simultaneously under visible light illumination is of great significance,but the fast recombination of photogenerated carriers in photocatalysts seriously decreases the conversion efficiency.Herein,a novel dual-functional 0D Cd_(0.5)Zn_(0.5)S/2D Ti_(3)C2 hybrid was fabricated by a solvothermally in-situ generated assembling method.The Cd_(0.5)Zn_(0.5)S nano-spheres with a fluffy surface completely and uniformly covered the ultrathin Ti_(3)C2 nanosheets,leading to the increased Schottky barrier(SB)sites due to a large contact area,which could accelerate the electron–hole separation and improve the light utilization.The optimized Cd_(0.5)Zn_(0.5)S/Ti_(3)C2 hybrid simultaneously presents a hydrogen evolution rate of 5.3 mmol/(g·h)and a benzaldehyde production rate of 29.3 mmol/(g·h),which are~3.2 and 2 times higher than those of pristine Cd_(0.5)Zn_(0.5)S,respectively.Both the multiple experimental measurements and the density functional theory(DFT)calculations further demonstrate the tight connection between Cd_(0.5)Zn_(0.5)S and Ti_(3)C2,formation of Schottky junction,and efficient photogenerated electron–hole separation.This paper suggests a dual-functional composite catalyst for photocatalytic hydrogen evolution and benzaldehyde production,and provides a new strategy for preventing the photogenerated electrons and holes from recombining by constructing a 0D/2D heterojunction with increased SB sites.
基金support from the National Natural Science Foundation of China(Nos.51802170,51772162,and 21801150)the Natural Science Foundation of Shandong Province(Nos.ZR2019MB001,ZR2018BEM014,and ZR2019JQ14)+3 种基金the Youth Innovation and Technology Foundation of Shandong Higher Education Institutions,China(No.2019KJC004)the Taishan Scholar Project of Shandong Province(No.ts201712047)the Special Fund Project to Guide Development of Local Science and Technology by Central Government,the Open Research Fund of State Key Laboratory of Inorganic Synthesis and Preparative Chemistry of Jilin University(No.2019-22)the Taishan Scholar Program of Advantage and Characteristic Discipline Team of Eco-Chemical Process and Technology.
文摘Photocatalytic water splitting for hydrogen(H_(2))production is a green sustainable technology,in which highly-efficient steady photocatalysts are fundamentally required.In this work,unique CdS/Cd_(0.5)Zn_(0.5)S-M0_(1-x)W_(x)S_(2) photocatalyst constructed by CdS hollow nano-spheres with successively surface-modified Cd_(0.5)Zn_(0.5)S shell and defect-rich MO_(1-x)W_(x)S_(2) ultrathin nanosheets was reported for the first time.Interestingly,the Cd_(0.5)Zn_(0.5)S shell could greatly enhance the photo-stability and reduce the carrier recombination of CdS.Meanwhile,enriching active sites and accelerating charge transfer could be achieved via anchoring defect-rich Mo_(1-x)W_(x)S_(2) onto CdS/Cd_(0.5)Zn_(0.5)S hollow heterostructures.Specifically,the optimized CdS/Cd_(0.5)Zn_(0.5)S-Mo_(1-x)W_(x)Sa(6 h Cd_(0.5)Zn_(0.5)S-coating,7 wt.%Mo_(1-x)W_(x)S_(2),x=0.5)hybrid delivered an exceptional H_(2) generation rate of 215.99 mmol·g^(-1)·h^(-1),which is approximately 502,134,and 23 times that of pure CdS,CdS/Cd_(0.5)Zn_(0.5)S,and 3 wt.%Pt-loaded CdS/Cd_(0.5)Zn_(0.5)S,respectively.Remarkably,a high H_(2) evolution reaction(HER)apparent quantum yield(AQY)of 64.81%was obtained under 420-nm irradiation.In addition,the CdS/Cd_(0.5)Zn_(0.5)S-Mo_(1-x)W_(x)S_(2) was also durable for H2 production under long-term irradiation.This work provides valuable inspirations to rational design and synthesis of efficient and stable hybrid photocatalysts for solar energy conversion.
