Hydrogen evolution reaction on palladium multilayers deposited on Au(111): a theoretical approach

PAOLA QUAINO; ELIZABETH SANTOS

LANGMUIR

AMER CHEMICAL SOC

Lugar: Washington; Año: 2015 vol. 31 p. 858 - 867

0743-7463

We have investigated the electrocatalytic properties of multilayers of Pd epitaxially deposited on Au(111). In contrast to the numerous previous works in this area, we have focused on the kinetics of the electrochemical step for hydrogen adsorption (Volmer reaction) and determined its energies of activation. We have used a combination of density functional theory calculations and our own theory of electrocatalysis, which allows us to investigate the systems in an electrochemical environment. Contrary to our previous work with a submonolayer of Pd in Au(111), the activation barrier for the hydrogen adsorption process from proton is very low or almost zero for all bimetallic systems investigated. It is about 0.2 eV for pure Pd(111). In the case of two layers of Pd about 0.2 eV for pure Pd(111). In the case of two layers of Pd on Au(111) containing absorbed hydrogen in the subsurface, thethan for the other investigated systems. This is in agreement withoxidation with hydride Pd systems.adsorption free energy is less negative and the barrier lower experimental data that shows a larger activity for hydrogen