Direct photoinduced synthesis and high H2-evolution performance of Bi-modified TiO2 photocatalyst in a Bi(III)-EG complex system

Abstract

Exploiting novel non-noble metal cocatalysts and their facile synthetic strategies are quite crucial to develop high-performance H2-production photocatalysts. Here, metallic Bi nanoparticle as a new H2-evolution cocatalyst was deposited on the TiO2 surface to significantly enhance its H2-evolution activity by a direct photoinduced method in a Bi(III)-EG complex system. Photocatalytic H2-production experimental results suggested that all the resultant Bi/TiO2 photocatalyst display a dramatically higher photocatalytic H2-production performance than the pure TiO2. Specifically, the Bi/TiO2(1 wt%) photocatalysts exhibited the highest H2-evolution activity (37.10 μmol h−1), which is higher than the naked TiO2 photocatalyst (0.35 μmol h−1) by a factor of 106 times. In addition to the TiO2, the metallic Bi nanoparticles can also serve as an effective cocatalyst to significantly improve the H2-evolution performance of the well-known visible-light responded g-C3N4 and CdS photocatalysts. According to the above result, an electron cocatalyst-mediated mechanism of metallic Bi is proposed for the enhanced H2-production activity, where the metallic Bi cocatalyst works as an electron capturer to rapidly accept photogenerated electrons from the TiO2 surface and subsequently functions as a H2-evolution active site to promote H2 formation. Compared with the widely used noble metals (such as Pt), the present promising Bi cocatalyst is one of the very important cocatalysts for the synthesis of highly efficient photocatalytic materials due to its low cost and abundance.