Electrochemical conversion of CO2 into fuels is a promising means to solve greenhouse effect and recycle chemical energy. However, the CO2 reduction reaction(CO2 RR) is limited by the high overpotential, slow kinetics...Electrochemical conversion of CO2 into fuels is a promising means to solve greenhouse effect and recycle chemical energy. However, the CO2 reduction reaction(CO2 RR) is limited by the high overpotential, slow kinetics and the accompanied side reaction of hydrogen evolution reaction. Au nanocatalysts exhibit high activity and selectivity toward the reduction of CO2 into CO. Here, we explore the Faradaic efficiency(FE)of CO2 RR catalyzed by 50 nm gold colloid and trisoctahedron. It is found that the maximum FE for CO formation on Au trisoctahedron reaches 88.80% at -0.6 V, which is 1.5 times as high as that on Au colloids(59.04% at -0.7 V). The particle-size effect of Au trisoctahedron has also been investigated, showing that the FE for CO decreases almost linearly to 62.13% when the particle diameter increases to 100 nm. The Xray diffraction characterizations together with the computational hydrogen electrode(CHE) analyses reveal that the(2 2 1) facets on Au trisoctahedron are more feasible than the(1 1 1) facets on Au colloids in stabilizing the critical intermediate COOH*, which are responsible for the higher FE and lower overpotential observed on Au trisoctahedron.展开更多
基金This work was supported by the National Key Research and Development Program of China(2017YFA0206500)the National Natural Science Foundation of China(21635004 and 21675079)Part of the numerical calculations were carried out in the High Performance Computing Center(HPCC)of Nanjing University.
文摘Electrochemical conversion of CO2 into fuels is a promising means to solve greenhouse effect and recycle chemical energy. However, the CO2 reduction reaction(CO2 RR) is limited by the high overpotential, slow kinetics and the accompanied side reaction of hydrogen evolution reaction. Au nanocatalysts exhibit high activity and selectivity toward the reduction of CO2 into CO. Here, we explore the Faradaic efficiency(FE)of CO2 RR catalyzed by 50 nm gold colloid and trisoctahedron. It is found that the maximum FE for CO formation on Au trisoctahedron reaches 88.80% at -0.6 V, which is 1.5 times as high as that on Au colloids(59.04% at -0.7 V). The particle-size effect of Au trisoctahedron has also been investigated, showing that the FE for CO decreases almost linearly to 62.13% when the particle diameter increases to 100 nm. The Xray diffraction characterizations together with the computational hydrogen electrode(CHE) analyses reveal that the(2 2 1) facets on Au trisoctahedron are more feasible than the(1 1 1) facets on Au colloids in stabilizing the critical intermediate COOH*, which are responsible for the higher FE and lower overpotential observed on Au trisoctahedron.
基金supported by the National Key Research and Development Program of China(2017YFA0206500)the National Natural Science Foundation of China(21635004,22004069,and 22227806)the Excellent Research Program of Nanjing University(ZYJH004).
