Bi2O2Se as a novel co-catalyst for photocatalytic hydrogen evolution reaction

To enhance the photocatalytic activity, co-catalysts are often utilized to accelerate rate-limited surface reactions. Herein, various amounts of bismuth oxyselenide (Bi2O2Se) (i.e., 5 to 25 wt%) as a novel co-catalyst were deposited on TiO2 nanoparticles for photocatalytic hydrogen evolution reaction. The 15% Bi2O2Se/TiO2 showed the best enhanced hydrogen production rate of 1240.7 μmol h−1g−1, which was about 50 times greater than that of pure TiO2. The SEM, EDX-Mapping and TEM revealed the mechanism of in-growth of Bi2O2Se on the TiO2. Trapping experiment of superoxide free radical (O2−) and transient photocurrent decay measurement also revealed that the recombination of the photogenerated electron–hole was remarkably suppressed in Bi2O2Se/TiO2 compared to pure TiO2. Detailed analysis of XPS, transient photocurrent responses, electrochemical impedance spectroscopy (EIS) and DFT calculations indicated that there is a strong interaction between Bi2O2Se and TiO2, and the electrons of TiO2 can be injected into Bi2O2Se. These findings show the potential of Bi2O2Se as co-catalytic materials and open a new avenue for solar water splitting.