Dopant Evolution in Electrocatalysts after Hydrogen Oxidation Reaction in an Alkaline Environment

Introduction of interstitialdopants has opened a new pathway tooptimize nanoparticle catalytic activity for, e.g., hydrogen evolution/oxidationand other reactions. Here, we discuss the stability of a property-enhancingdopant, B, introduced through the controlled synthesis of an electrocatalystPd aerogel. We observe significant removal of B after the hydrogenoxidation reaction. Ab initio calculations show thatthe high stability of subsurface B in Pd is substantially reducedwhen H is adsorbed/absorbed on the surface, favoring its departurefrom the host nanostructure. The destabilization of subsurface B ismore pronounced, as more H occupies surface sites and empty interstitialsites. We hence demonstrate that the H-2 fuel itself favorsthe microstructural degradation of the electrocatalyst and an associateddrop in activity.