Surface modification of the TiO2/g-CN core-shell nanostructure with bimetallic NiMoO4 nanosheets for the improved photoelectrochemical water oxidation

Abstract

TiO2/g-CN based photocatalyst has been widely studied for its easy synthesis and outstanding charge separation efficiency. However, the difficulty in obtaining a high photocurrent value limits its application in photoelectrocatalysis water splitting. In this article, bimetallic NiMoO4 nanosheets co-catalyst was decorated onto TiO2/g-CN heterojunction to form TiO2/g-CN/NiMoO4 3D nanostructure. We obtained a photocurrent density as high as 1.8 mA/cm2 under 1 sun illumination at 1.23 V versus RHE, which is 2 times higher than that of pristine TiO2 nanorods arrays (NRs). The improved performance mainly comes from two aspects. One is g-CN expands the response range to visible light, and forms a heterojunction with TiO2, which improves the efficiency of charge separation at the same time. The other is that the addition of bimetallic NiMoO4 nanosheets oxygen evolution co-catalyst increases the surface active sites, and reduces the surface reaction barrier to promote oxidation reaction.