Abstract
Supported by carbon materials and adjusting Ag surface states by metal oxides are two effective methods to promote the oxygen reduction reaction (ORR) performance of Ag-based catalysts. Herein, combining these two strategies, two kind of heterostructural electrocatalysts, carbon nanotubes-supported Ag/MoO 2 (CNTs-Ag/MoO 2 ) and carbon nanotubes-supported Ag/MnO 2 (CNTs-Ag/MnO 2 ) are constructed by facile two-step methods for the superior ORR catalytic activity in alkaline medium. Both CNTs-Ag/MoO 2 and CNTs-Ag/MnO 2 exhibit more positive onset potential and higher half-wave potential (~0.93 V and ~ 0.81 V (vs RHE) for CNTs-Ag/MoO 2 , ~0.99 V and ~ 0.86 V (vs RHE) for CNTs-Ag/MnO 2 ), comparable and even superior to commercial Pt/C(~0.95 V and ~ 0.82 V(vs RHE)), which are benefit from Ag surface states regulation and the oxygen vacancy formation induced by the introduction of MoO 2 or MnO 2 , as well as the enhanced electron transmission and dispersion of Ag/MoO 2 or Ag/MnO 2 resulted from the activated CNTs supporting. This work provides a useful reference to design efficient Ag-based ORR electrocatalysts with the superior performance. • Ag-based catalysts CNTs-Ag/MoO 2 , CNTs-Ag/MnO 2 are constructed by a two-step method. • CNTs-Ag/MnO 2 exhibits the optimal ORR activity, superior to the commercial Pt/C. • MoO 2 , MnO 2 adjust Ag surface states, facilitating the kinetics of O O bond breakage. • CNTs frame help the active substances good dispersion and high charge transportation.
Published Version
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