Advantageous Interfacial Effects of AgPd/g-C3 N4 for Photocatalytic Hydrogen Evolution: Electronic Structure and H2 O Dissociation.

ABSTRACT

Bimetallic AgPd nanoparticles have been synthesized before, but the interfacial electronic effects of AgPd on the photocatalytic performance have been investigated less. In this work, the results of hydrogen evolution suggest that the bimetallic AgPd/g-C3 N4 sample has superior activity to Ag/g-C3 N4 and Pd/g-C3 N4 photocatalysts. The UV/Vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, CO adsorption diffuse reflectance FTIR spectroscopy, and FTIR results demonstrate that in the AgPd/g-C3 N4 , the surface electronic structures of Pd and Ag are changed, which is beneficial for faster photogenerated electron transfer and greater H2 O molecule adsorption. In situ ESR spectra suggest that, under visible light irradiation, there is more H2 O dissociation to radical species on the AgPd/g-C3 N4 photocatalyst. Furthermore, DFT calculations confirm the interfacial electronic effects of AgPd/g-C3 N4 , that is, Pdδ- ⋅⋅⋅Agδ+ , and the activation energy of H2 O molecule dissociation on AgPd/g-C3 N4 is the lowest, which is the main contributor to the enhanced photocatalytic H2 evolution.