Fabrication of an efficient noble metal-free TiO2-based photocatalytic system using Cu–Ni bimetallic deposit as an active center of H2 evolution from water

Abstract

Cu and Ni co-modified TiO2 nanoparticles (P25) were prepared by a simple hydrothermal process. Meanwhile, photocatalytic H2 evolution from water over the as-prepared Cu and Ni co-modified TiO2 nanoparticles was explored using methanol as a sacrificial reagent. The results indicate that the Cu and Ni co-modified TiO2 nanoparticles is an efficient and stable photocatalyst for photocatalytic hydrogen evolution from methanol aqueous solution. During the first 5-h irradiation, the rate is up to 13.5mmolh−1g−1. Moreover, the photocatalytic activity of the Cu and Ni co-modified TiO2 nanoparticles can remain almost unchanged after two successive cycles. And the hydrogen evolution rate is still up to 4.62mmolh−1g−1 in the eighth cycle. Therein, Cu–Ni bimetallic deposit serves as charge transferring sites and/or active sites, and plays an important role in the photocatalytic hydrogen evolution. The dramatic photocatalytic activity of the Cu and Ni co-modified TiO2 nanoparticles may be ascribed to the synergy effect between Cu and Ni. At last, the photocatalytic hydrogen evolution was studied as a function of content of Cu–Ni bimetallic deposit, molar ratio of Cu to Ni, hydrothermal reaction temperature, hydrothermal reaction time, pH, dosage of photocatalyst and concentration of sacrificial reagent, respectively.