Z-Scheme g-C3N4/Bi4NbO8Cl Heterojunction for Enhanced Photocatalytic Hydrogen Production

Photocatalytic water splitting is promising for sustainable energy development, but it is severely challenged by the low charge separation efficiency and slashing redox potentials requirement. Fabricating a Z-scheme heterojunction as an effective strategy for solving the aforementioned troubles gains enormous efforts. In this work, we develop high-efficiency Z-scheme catalyst g-C 3 N 4 /Bi 4 NbO 8 Cl based on a facile high-energy ball-milling method to form an intimate interface between the two phases. It exhibits an enormously promoted photocatalytic activity for H 2 production with visible-light illumination (λ > 420 nm), and the H 2 evolution rate is 6.9 and 67.2 times higher than those of bare g-C 3 N 4 and Bi 4 NbO 8 Cl, respectively. The stronger photoabsorption of g-C 3 N 4 /Bi 4 NbO 8 Cl (beyond 500 nm) allows generation of more photons than does g-C 3 N 4 . More importantly, the separation and transfer of photoexcited charge carriers were greatly improved between g-C 3 N 4 and Bi 4 NbO 8 Cl, as revealed by the photoelectrochemical and time-resolved photoluminescence decay results. The Z-scheme charge transfer mechanism of g-C 3 N 4 /Bi 4 NbO 8 Cl was also manifested by electron spin resonance (ESR). The work furnishes a new solution to fabrication of high-efficiency Z-scheme catalysts for countering energy issues.