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 (Bi 2 O 2 Se) ( i.e. , 5 to 25 wt%) as a novel co-catalyst were deposited on TiO 2 nanoparticles for photocatalytic hydrogen evolution reaction. The 15% Bi 2 O 2 Se/TiO 2 showed the best enhanced hydrogen production rate of 1240.7 μmol h −1 g −1 , which was about 50 times greater than that of pure TiO 2 . The SEM, EDX-Mapping and TEM revealed the mechanism of in-growth of Bi 2 O 2 Se on the TiO 2. Trapping experiment of superoxide free radical (O 2 − ) and transient photocurrent decay measurement also revealed that the recombination of the photogenerated electron–hole was remarkably suppressed in Bi 2 O 2 Se/TiO 2 compared to pure TiO 2 . Detailed analysis of XPS, transient photocurrent responses, electrochemical impedance spectroscopy (EIS) and DFT calculations indicated that there is a strong interaction between Bi 2 O 2 Se and TiO 2 , and the electrons of TiO 2 can be injected into Bi 2 O 2 Se. These findings show the potential of Bi 2 O 2 Se as co-catalytic materials and open a new avenue for solar water splitting.