Hydrogen oxidation reaction on Pd(1 1 1) electrode in alkaline media: Ab-initio DFT study of OH effects

Abstract

OH effects on the hydrogen oxidation reaction, during a metallic surface electrocatalysis, have been studied by using density functional theory (DFT) based first principles methods. The hydrogen reaction is carried out on Pd(111) surface with the help of Tafel’s hydrogen adsorption and Volmer’s alkaline reactions. Both the reactions are investigated in detail by performing Broyden–Fletcher–Goldfarb–Shanno (BFGS) type structural relaxation analysis. Relative changes in structural free energies, hydrogen adsorption, water formation parameters and electronic structure of atomic orbitals corresponding to the palladium surface and adsorbent atoms are studied during the reaction. A significant change in local density of states of s-, p-, and d-band states of the involved entities is obtained in respect to before- and after-water-formation circumstances. Spectral variations in the local density of states (LDOS) are discussed vis-à-vis the HOR, hydrogen adsorption and validation of the presence of water.