Although nanostructures based on noble metal alloys are widely utilized in （electro）catalysis, their low-temperature synthesis remains an enormous challenge due to the different Nernst equilibrium potentials of meta...Although nanostructures based on noble metal alloys are widely utilized in （electro）catalysis, their low-temperature synthesis remains an enormous challenge due to the different Nernst equilibrium potentials of metal precursors. Herein, we describe the successful synthesis of trimetallic PtRhNi alloy nanoassemblies （PtRhNi-ANAs） with tunable Pt/Rh ratios using a simple mixed cyanogel reduction method and provide a detailed characterization of their chemical composition, morphology, and structure. Additionally, the electrochemical properties of PtRhNi-ANAs are examined by cyclic voltammetry, revealing composition- dependent electrocatalytic activity in the ethanol oxidation reaction （EOR）. Compared to a commercial Pt black electrocatalyst, optimized Pt3Rh1Ni2-ANAs display remarkably enhanced EOR electrocatalytic performance in alkaline media.展开更多
The development of active and methanol-tolerant cathode electrocatalysts for the oxygen reduction reaction （ORR） is extremely important for accelerating the commercial viability of direct methanol fuel cells （DMFCs...The development of active and methanol-tolerant cathode electrocatalysts for the oxygen reduction reaction （ORR） is extremely important for accelerating the commercial viability of direct methanol fuel cells （DMFCs）. In this work, we present an efficient and template-free route for facile synthesis of cyanide （CN^-）-functionalized PtNi hollow nanospheres （PtNi@CN HNSs） with a high alloying degree using a simple cyanogel reduction method at room temperature. The physical and electrocatalytic properties of the PtNi@CN HNSs were investigated by various physical and electrochemical techniques. The PtNi@CN HNSs exhibited significantly enhanced electrocatalytic activity, durability, and particular methanol tolerance for the ORR as compared to commercial Pt black, and thus they are promising cathode electrocatalysts for DMFCs.展开更多
The research on electrocatalysts with relatively lower price than Pt and excellent electrocatalytic performance for the cathode oxygen reduction reaction(ORR) and anode methanol oxidation reaction(MOR) is vital for th...The research on electrocatalysts with relatively lower price than Pt and excellent electrocatalytic performance for the cathode oxygen reduction reaction(ORR) and anode methanol oxidation reaction(MOR) is vital for the development of direct methanol fuel cells(DMFCs). In this work, we develop a cyanogel-reduction method to synthesize reduced graphene oxide(rGO) supported highly dispersed PdNi alloy nanocrystals(PdNi/rGO) with high alloying degree and tunable Pd/Ni ratio. The large specific surface area and the d-band center downshift of Pd result in excellent activity of Pd4 Ni1/rGO nanohybrids for the ORR. The modification of Pd electronic structure can facilitate the adsorption of CH3 OH on Pd surface and the highly oxophilic property of Ni can eliminate/mitigate the COadsintermediates poisoning, which make PdNi/r GO nanohybrids possess superior MOR activity. In addition, rGO improve the stability of PdNi alloy nanocrystals for the ORR and MOR. Due to high activity and stability for the ORR and MOR, PdNi/rGO nanohybrids are promising to be an available bifunctional electrocatalyst in DMFCs.展开更多
Integration of fast electrochemical double-layer capacitance and large pseudocapacitance is a practical way to improve the overall capability of supercapacitor,yet remains challenging.Herein,an effective cyanogel synt...Integration of fast electrochemical double-layer capacitance and large pseudocapacitance is a practical way to improve the overall capability of supercapacitor,yet remains challenging.Herein,an effective cyanogel synthetic strategy was demonstrated to prepare ultrathin Ni(OH)2 nanosheets coupling with conductive reduced graphene oxide(rGO)(rGO-Ni(OH)2)at ambient condition.Ultrathin Ni(OH)2 nanosheet with 3–4 layers of edge-sharing octahedral MO6 maximally exposes the active surface of Faradic reaction and promotes the ion diffusion,while the conductive rGO sheet boosts the electron transport during the reaction.Even at 30 A g−1,the optimal sample can deliver a specific capacitance of 1119.52 F g−1,and maintain 82.3%after 2000 cycles,demonstrating much higher electrochemical capability than bare Ni(OH)2 nanosheets.A maximum specific energy of 44.3 W h kg^−1(148.5 W kg^−1)is obtained,when assembled in a two-electrode system rGO-Ni(OH)2//rGO.This study provides an insight into efficient construction of two dimensional hybrid electrodes with high performance for the new-generation energy storage system.展开更多
As a representative type of self-supported templates, cyano-bridged cyanogels provide ideal plateaus for synthesis of three-dimensional(3 D) nanostructures. Herein, 3 D pomegranate-like Fe-doped NiCo nanoassemblies(3 ...As a representative type of self-supported templates, cyano-bridged cyanogels provide ideal plateaus for synthesis of three-dimensional(3 D) nanostructures. Herein, 3 D pomegranate-like Fe-doped NiCo nanoassemblies(3 D PG-NiCoFe NAs) were synthesized via facile one-step bi-component cyanogel reduction with NaBH_4 as the reducing agent. Specifically, the influence of the incorporated Fe amount was carefully investigated by finely adjusting the feeding molar ratios of the Ni/Co/Fe atoms in the precursors.By virtue of the unique structure and enriched oxygen vacancies originated from well-modulated electronic structures, the 3 D PG-NiCoFe-211 NAs exhibited outstanding electrocatalytic performances for oxygen evolution reaction(OER) in alkaline solution, outperforming commercial RuO_2 catalyst. The current incorporation of foreign metal atom into host material provides some valuable insights into design and synthesis of metal-based nanocatalysts for constructing practical water splitting devices.展开更多
A novel carbon-supported cyanogel （C@cyanogel）-derived strategy is used to synthesize an intermetallic Pd3Fe/C compound of the desired ordered Pd3Fe phase with a small particle size. The novelty of this work lies in...A novel carbon-supported cyanogel （C@cyanogel）-derived strategy is used to synthesize an intermetallic Pd3Fe/C compound of the desired ordered Pd3Fe phase with a small particle size. The novelty of this work lies in using carbon- supported K2PdHCl4/K4Fe^Ⅱ（CN）6 cyanogel as a reaction precursor, generated through the substitution of two chloride ligands by the nitrogen ends of the cyanide ligands on the metal center. The inherent nature of cyanogels can effectively suppress the movement of Pd^0 and Fe^0 nuclei in the crystal, benefiting the formation of the intermetallic, which is otherwise challenging via traditional synthesis techniques. The ordered Pd3Fe/C catalyst exhibits excellent catalytic activity and good cycle stability for the formic acid oxidation （FAO） reaction relative to the properties of disordered Pd3Fe/C and commercial Pd/C catalysts, dernonstrating that the ordered Pd3Fe/C is a promising replacement for commercial Pd-based catalysts. The outstanding performance can be ascribed to the full isolation of active sites in the ordered Pd3Fe structure and the modified electronic structure of the active components. This work provides an effective and novel route to obtain Pd-based intermetallic compounds with potential applications in a wide range of electrocatalysis.展开更多
基金Acknowledgements We acknowledge financial support by the National Natural Science Foundation of China （Nos. 21473111 and 21376122）, Fundamental Research Funds for the Central Universities （No. GK201602002）, Innovation Foundation of Shenzhen Government （No. JCYJ20160408173202143）, the Joint Fund of Energy Storage of Qingdao （No. 20160012）, and the Fundamental Research Funds of Huazhong University of Science and Technology （Nos. 3004013109 and 0118013089）. We acknowledge the support of Analytical and Testing Center of Huazhong University of Science and Technology for SEM and XPS measurements.
文摘Although nanostructures based on noble metal alloys are widely utilized in （electro）catalysis, their low-temperature synthesis remains an enormous challenge due to the different Nernst equilibrium potentials of metal precursors. Herein, we describe the successful synthesis of trimetallic PtRhNi alloy nanoassemblies （PtRhNi-ANAs） with tunable Pt/Rh ratios using a simple mixed cyanogel reduction method and provide a detailed characterization of their chemical composition, morphology, and structure. Additionally, the electrochemical properties of PtRhNi-ANAs are examined by cyclic voltammetry, revealing composition- dependent electrocatalytic activity in the ethanol oxidation reaction （EOR）. Compared to a commercial Pt black electrocatalyst, optimized Pt3Rh1Ni2-ANAs display remarkably enhanced EOR electrocatalytic performance in alkaline media.
基金This research was sponsored by National Natural Science Foundation of China （Nos. 21473111 and 21376122）, Natural Science Foundation of Shaanxi Province （No. 2015JM2043）, and Fundamental Research Funds for the Central Universities （No. GK201602002）.
文摘The development of active and methanol-tolerant cathode electrocatalysts for the oxygen reduction reaction （ORR） is extremely important for accelerating the commercial viability of direct methanol fuel cells （DMFCs）. In this work, we present an efficient and template-free route for facile synthesis of cyanide （CN^-）-functionalized PtNi hollow nanospheres （PtNi@CN HNSs） with a high alloying degree using a simple cyanogel reduction method at room temperature. The physical and electrocatalytic properties of the PtNi@CN HNSs were investigated by various physical and electrochemical techniques. The PtNi@CN HNSs exhibited significantly enhanced electrocatalytic activity, durability, and particular methanol tolerance for the ORR as compared to commercial Pt black, and thus they are promising cathode electrocatalysts for DMFCs.
基金the National Natural Science Foundation of China (21473111)the Fundamental Research Funds for the Central Universities (GK201701007)
文摘The research on electrocatalysts with relatively lower price than Pt and excellent electrocatalytic performance for the cathode oxygen reduction reaction(ORR) and anode methanol oxidation reaction(MOR) is vital for the development of direct methanol fuel cells(DMFCs). In this work, we develop a cyanogel-reduction method to synthesize reduced graphene oxide(rGO) supported highly dispersed PdNi alloy nanocrystals(PdNi/rGO) with high alloying degree and tunable Pd/Ni ratio. The large specific surface area and the d-band center downshift of Pd result in excellent activity of Pd4 Ni1/rGO nanohybrids for the ORR. The modification of Pd electronic structure can facilitate the adsorption of CH3 OH on Pd surface and the highly oxophilic property of Ni can eliminate/mitigate the COadsintermediates poisoning, which make PdNi/r GO nanohybrids possess superior MOR activity. In addition, rGO improve the stability of PdNi alloy nanocrystals for the ORR and MOR. Due to high activity and stability for the ORR and MOR, PdNi/rGO nanohybrids are promising to be an available bifunctional electrocatalyst in DMFCs.
基金the National Natural Science Foundation of China(21875133)Xijiang R&D Team(Wang X),the Science and Technology Program of Guangzhou(2019050001)Science and Technology Commission of Shanghai Municipality(19ZR1479500)。
文摘Integration of fast electrochemical double-layer capacitance and large pseudocapacitance is a practical way to improve the overall capability of supercapacitor,yet remains challenging.Herein,an effective cyanogel synthetic strategy was demonstrated to prepare ultrathin Ni(OH)2 nanosheets coupling with conductive reduced graphene oxide(rGO)(rGO-Ni(OH)2)at ambient condition.Ultrathin Ni(OH)2 nanosheet with 3–4 layers of edge-sharing octahedral MO6 maximally exposes the active surface of Faradic reaction and promotes the ion diffusion,while the conductive rGO sheet boosts the electron transport during the reaction.Even at 30 A g−1,the optimal sample can deliver a specific capacitance of 1119.52 F g−1,and maintain 82.3%after 2000 cycles,demonstrating much higher electrochemical capability than bare Ni(OH)2 nanosheets.A maximum specific energy of 44.3 W h kg^−1(148.5 W kg^−1)is obtained,when assembled in a two-electrode system rGO-Ni(OH)2//rGO.This study provides an insight into efficient construction of two dimensional hybrid electrodes with high performance for the new-generation energy storage system.
基金supported by the National Natural Science Foundation of China (No. 21805245)the Zhejiang Public Welfare Technology Application Research Project (LGG19B050001)the National Students’ Innovation and Entrepreneurship Training Program of Zhejiang Normal University (201910345032, Z.J. Wang)。
文摘As a representative type of self-supported templates, cyano-bridged cyanogels provide ideal plateaus for synthesis of three-dimensional(3 D) nanostructures. Herein, 3 D pomegranate-like Fe-doped NiCo nanoassemblies(3 D PG-NiCoFe NAs) were synthesized via facile one-step bi-component cyanogel reduction with NaBH_4 as the reducing agent. Specifically, the influence of the incorporated Fe amount was carefully investigated by finely adjusting the feeding molar ratios of the Ni/Co/Fe atoms in the precursors.By virtue of the unique structure and enriched oxygen vacancies originated from well-modulated electronic structures, the 3 D PG-NiCoFe-211 NAs exhibited outstanding electrocatalytic performances for oxygen evolution reaction(OER) in alkaline solution, outperforming commercial RuO_2 catalyst. The current incorporation of foreign metal atom into host material provides some valuable insights into design and synthesis of metal-based nanocatalysts for constructing practical water splitting devices.
文摘A novel carbon-supported cyanogel （C@cyanogel）-derived strategy is used to synthesize an intermetallic Pd3Fe/C compound of the desired ordered Pd3Fe phase with a small particle size. The novelty of this work lies in using carbon- supported K2PdHCl4/K4Fe^Ⅱ（CN）6 cyanogel as a reaction precursor, generated through the substitution of two chloride ligands by the nitrogen ends of the cyanide ligands on the metal center. The inherent nature of cyanogels can effectively suppress the movement of Pd^0 and Fe^0 nuclei in the crystal, benefiting the formation of the intermetallic, which is otherwise challenging via traditional synthesis techniques. The ordered Pd3Fe/C catalyst exhibits excellent catalytic activity and good cycle stability for the formic acid oxidation （FAO） reaction relative to the properties of disordered Pd3Fe/C and commercial Pd/C catalysts, dernonstrating that the ordered Pd3Fe/C is a promising replacement for commercial Pd-based catalysts. The outstanding performance can be ascribed to the full isolation of active sites in the ordered Pd3Fe structure and the modified electronic structure of the active components. This work provides an effective and novel route to obtain Pd-based intermetallic compounds with potential applications in a wide range of electrocatalysis.
