Hydrogen and oxygen recombination reaction on Pt-Ni and Pt-Co based alloys using density functional theory

Density functional theory (DFT) calculations were used to investigate the surface performance of Pt, Ni, Co, and PtxTM1-x (0 < x < 1) alloys, as well as reaction intermediates (O, H, OH, OH + H, H2O) on these surfaces for H2/ O2 recombination. The activity of the PtxTM1-x alloys towards H2/O2 recombination reaction was probed using adsorption energies and reaction energies. The Pt3Co, Pt3Ni and PtNi3 alloys were found to be stable along the (111) miller index, with strong surface adsorption occurring on the PtNi3 (111) surface and weaker adsorption on the Pt3Co (111) surface. Enhanced reactivity was observed on the Pt3Ni and Pt3Co (111) surfaces for the (O* + H*-* OH*) reaction step, while the Pt (111) surface was most suited for the (OH* + H*-* H2O) reaction step. The OH* formation reaction step was inhibited on the PtNi3 (111) surface due to the strong surface absorption of the reaction intermediates. Overall, these results suggest that the Pt3Co (111) surface is a promising alternative catalyst for H2/O2 recombination compared to pristine Pt due to its performance in the O + H adsorption and OH* formation steps.