Silver-doped γ-MnO2 for Oxygen Evolution Reaction in Acidic Media
Water electrolysis with a proton exchange membrane(PEM)is an important technology for hydrogen production.The development of non-precious metal-based electrocatalysts that catalyze the oxygen evolution reaction efficiently and stably in acidic media is of great importance,but remains a major challenge.In this work,Ag is doped into γ-MnO2(MO)to develop an Ag-MnO2(AMO)electrocatalyst that enables a highly efficient acidic oxygen evolution reaction.We find that Ag doping optimizes the electronic structure of MO and improves its charge transfer ability.Therefore,AMO electrodes show much better oxygen evolution activity than MO electrodes.The optimized 7.5AMO electrode delivers current densities of 10 mA·cm-2 at overpotentials of 398 mV in a 1.0 mol·L-1 sulfuric acid solution,which is 28 mV less than the MO electrode.In addition,Ag doping significantly improves the stability of the MO for the acidic oxygen evolution reaction.At a high current density of 100 mA·cm-2,the 7.5AMO electrode maintains a stable potential for more than 500 h.Even more impressively,it remains stable for more than 50 h at a current density of 500 mA·cm-2.As far as we know,this is one of the most stable non-precious metal-based electrocatalysts for the acidic oxygen evolution reaction at high current densities.
electrolytic water splittingoxygen evolution reactionγ-MnO2silver-dopingnon-precious metal
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