Rational design of BiOBr/Ov-TiO2-Cu photocatalyst for efficient nitrogen reduction to ammonia

The lack of active sites and the low availability of photoelectrons severely limit the photocatalytic reduction of nitrogen to ammonia in semiconductor materials. Here, we successfully designed a BiOBr/Ov-TiO2-Cu heterojunction catalyst toward N2 fixation into NH3. The optimized BiOBr/Ov-TiO2-Cu heterojunction has a promising photocatalytic performance and stability with the highest NH3 yield of 259.82 μmol·g-1·h-1. The combination of detailed theoretical simulation calculations and comprehensive characterizations indicates the BiOBr/Ov-TiO2-Cu heterojunction with oxygen vacancy (Ov) stabilized Cu nanoparticles (NPs) as active sites can effectively adsorb and activate N2 molecules. The close contact between BiOBr and Ov-TiO2 elevates the quick transmission of photogenerated electrons at the interface and the enrichment on Cu NPs. This work not only provides an efficient photocatalyst for the N2 reduction, but also supplies theoretical support for identifying the active sites and charge transfer kinetics of the nitrogen reduction reaction.