TiO 2 @BTTA‐COF Hollow Microspheres S‐Scheme Heterojunction for Photocatalytic Hydrogen Production

ABSTRACT Solar‐driven photocatalytic water splitting for H 2 production is a promising sustainable strategy to solve severe environmental and energy crises caused by fossil fuel overexploitation. However, TiO 2 suffers from narrow UV‐limited light absorption and rapid electron‐hole recombination. Herein, TiO 2 @BTTA‐COF S‐scheme heterojunction with core–shell hollow microsphere structure was fabricated via in situ growth of BTTA‐COF on the surface of TiO 2 hollow microspheres. The optimized TiO 2 @BTTA‐80 exhibited a superior hydrogen evolution rate (1163.48 µmol g −1 h −1 ), exceeding pure TiO 2 (16.89 µmol g −1 h −1 ) and BTTA‐COF (531.08 µmol g −1 h −1 ). Systematic characterizations (X‐ray photoelectron spectroscopy, photoluminescence, photoelectrochemical tests) confirmed that the enhanced performance originated from expanded visible light absorption and S‐scheme charge transfer, which suppressed the recombination of photo‐induced carriers. This work provided a feasible strategy for designing high‐efficiency TiO 2 ‐based S‐scheme heterojunction photocatalysts.