Electronic Structure and Optical Properties of Nb2O5 Photo-Catalyst Calculated By Density Functional Method

Abstract

Recently, there has been attempts to increase the photo-catalytic activities of Nb2O5 with the addition of carbon modifications [1-4]. It has been proposed that carbonate species on the modified Nb2O5 act as surface sensitizer, which extends the photo-catalytically active region of Nb2O5 into the visible range [1-3]. Experiments have shown the photo-catalytic activity of these carbon-modified Nb2O5 structures are higher than of non-carbon-modified Nb2O5 and carbon-modified meso-porous TiO2 [1]. These carbon-modified Nb2O5 structures are promising candidates for photo-catalytic water splitting and more research is needed to understand these materials at the atomic scale. Here, we propose a DFT study of carbon-modified Nb2O5 (001) plane. The aim of this study is to determine the source of activity gain through electronic structure calculations. First, ground state, density of states, energy band structures, and optical properties of carbon-modified Nb2O5 are calculated. The electronic interaction between carbon and Nb2O5 will also be examined to determine its contribution to modify adsorption of intermediate species such as O2, H2, and OH. Band edge potentials and band gaps as calculated indicate the potential for driving the water cleavage reaction using solar energy. These results as presented point to a set of design guidelines for optimizations of photo-catalytic activity of Nb2O5.