Effect of Substitutionally Doped Graphene on the Activity of Metal Nanoparticle Catalysts for the Hydrogen Oxidation Reaction

Increasing the activity of non-noble catalysts for hydrogen oxidation is crucial in enhancing the efficiency of hydroxide exchange membrane fuel cells. Herein, we study the impact of graphene and nitrogen- and boron-doped graphene supports on the hydrogen oxidation reaction occurring on Ni, Cu, and Ag nanoparticles using first-principles calculations and published experimental data. We find that doping of graphene leads to a stronger interaction between the nanoparticle and the support, consequently weakening hydrogen adsorption. This leads to increased activity of supported Ni nanoparticles, but decreased activity of supported Cu and Ag nanoparticles. The dopant-induced changes in the hydrogen adsorption energies are quantitatively as important as the adsorption site. To describe adsorption energies for each supported nanoparticle, principal component analysis is introduced to systematically identify molecular descriptors of adsorption energy. Finally, a size-dependent activity model is formulated to close the size gap between first-principles calculations and experiments.