Surface Cl-Doped Bi₂WO₆/Bi_3.84W_0.16O_6.24 Nanosheets with Type-II Heterojunctions for Photocatalytic CO₂ Conversion

Electronic structure regulation is a fundamental strategy to optimize the surface properties of photocatalysts. Herein, a nanoscale Cl-doped Bi2WO6/Bi3.84W0.16O6.24 heterojunction (labeled as BWO/FBWO-Cl) catalyst with optimized band structure and rearranged surface charge has been synthesized via a facile one-step hydrothermal method. The experiment combined with theory verified that the adsorption and activation of CO2 were improved by Cl doping. The type-II heterojunction formed at the nanoscale could facilitate the rapid separation and transfer of photogenerated e–/h+ pairs. The optimized BWO/FBWO-Cl exhibits enhanced CO yield, which is 1.85 times and 4.82 times than that of BWO-Cl and FBWO-Cl, respectively. During 10 h irradiation, the CO yield continuously increasing over BWO/FBWO-Cl, indicating its superior photocatalytic stability. The in situ DRIFTS analysis and DFT calculations further proved that the boosting of CO2-to-CO benefits from the decreased formation energy barriers of COOH* by the synergistic effect of heterojunction and doped Cl. This work proposed an insight into the synthesis and mechanism study of efficient nanoscale photocatalysts.