The engineered interfacial Pd-O-Ti sites on the TiO2 nanobelts to accelerate water dissociation for the alkaline hydrogen evolution

Abstract

Electrochemical water splitting derived by the renewable electricity is one attractive route to produce the green hydrogen. The hydrogen evolution reaction (HER) at the cathode side under the alkaline condition is relatively difficult compared with the acidic, because there is a rate-determining step of breaking strong H-OH bonding in the water molecular. Herein, the ultrafine Pd nanoparticles are uniformly distributed on the TiO₂ nanobelts (Pd_NPs/TiO₂) by the pulsed laser deposition to expose the abundant interfacial sites, showing a lower HER overpotential of 71 mV at the current density of -10 mA cm^-2 in 1 M KOH. The interfacial Pd-O-Ti structure on Pd_NPs/TiO₂ provides the direct contact between active phase and the water molecules, contributing to break H-OH bond. At the same time, a selective adsorption of H on Pd and OH intermediate on TiO₂ is achieved in the interfacial Pd-O-Ti sites under the alkaline HER, optimizing the whole catalytic dynamic.