The construction of Cs 3 Mo x Sb y Br 9 /BiVO 4 S-scheme heterojunction photocatalyst for efficient photocatalytic N 2 fixation

Synergistic nitrogen (N 2 ) reduction with water (H 2 O) oxidation is meaningful but challenging owing to the inertness of the N 2 molecule and the sluggish kinetics of H 2 O oxidation. Herein, a simutaneous-promotion strategy of redox capacities is presented for constructing a lead-free Cs 3 Sb 2 Br 9 -based S -scheme heterojunction, by decorating Mo-functionalized Cs 3 Sb 2 Br 9 nanocrystals (Cs 3 Mo x Sb y Br 9 ) on BiVO 4 nanosheet through an in -situ plane -to -point growth manner. The Mo-functionalization for Cs 3 Sb 2 Br 9 enables the regulation of the d -band center position, greatly improving surface reaction kinetics for N 2 reduction. Furthermore, the construction of the S -scheme heterojunction enhances the driving force for H 2 O oxidation and spatial charge separation of photocatalysts. As anticipated, the resultant Cs 3 Mo x Sb y Br 9 /BiVO 4 exhibits an excellent photocatalytic N 2 reduction activity under ambient atmosphere, achieving ammonia (NH 3 ) production at a rate of 300 +/- 5 mu mol g -1 h -1 under simulated sunlight illumination (100 mW cm -2 ), which is nearly 20 -fold higher than that of pristine Cs 3 Sb 2 Br 9 .