Understanding surface charge effects in electrocatalysis. Part 2: Hydrogen peroxide reactions at platinum

Electrocatalytic activity is influenced by the surface charge on solid catalyst. Conventionally, our attention has been focused how shapes electric potential and concentration of ionic reactant(s) in local reaction zone. Taking H2O2 redox reactions at Pt(111) as a model system, we reveal peculiar effect using ab initio molecular dynamics simulations electrified Pt(111)-water interfaces. In this scenario, negative repels O–O bond reactant (H2O2) farther away from electrode surface. This leads to higher activation barrier for breaking bond. Incorporating microscopic mechanism into microkinetic-double-layer model, are able semi-quantitatively interpret pH-dependent Pt(111), especially anomalously suppressed reduction with decreasing potential. The relevance present also examined wider scenarios different electrolyte cations, solution pHs, crystal facets catalyst, parameters. contrast previous mechanisms focusing influences condition fixed plane, work gives an example which location plane adjusted charge.