Bi4TaO8Cl/Bi heterojunction enables high-selectivity photothermal catalytic conversion of CO2-H2O flow to liquid alcohol

A novel Bi 4 TaO 8 Cl/Bi heterojunction was prepared by in-situ growth of Bi nanometal on Bi 4 TaO 8 Cl nanosheet. It displayed a high photothermal catalytic activity for CO 2 reduction to C1+ fuels. A high selectivity of 92% for liquid alcohol (methanol, ethanol) can be achieved in a flow reactor at 473 K under solar light. The Bi 4 TaO 8 Cl/Bi photothermal catalysis outperforms Bi 4 TaO 8 Cl photothermal catalysis as well as Bi 4 TaO 8 Cl/Bi photocatalysis. • Bismuth metal is loaded on Bi 4 TaO 8 Cl in situ. • Bi 4 TaO 8 Cl/Bi heterojunction is studied as photothermal catalyst. • The heating rate of Bi 4 TaO 8 Cl is increased by ca. 120 °C/s by bismuth loading. • A continuous flow reduction of CO 2 with H 2 O is achieved. • Selectivity of liquid alcohol can reach 92% under solar light. The high-selectivity solar-driven catalytic production of value-added fuels, such as liquid alcohol from CO 2 , represents an ideal energy storage and conversion pathway. However, catalysts facilitating a practical CO 2 reduction approach are currently unavailable. The present work addresses this issue by developing a novel Bi 4 TaO 8 Cl/Bi heterojunction. The Bi 4 TaO 8 Cl/Bi heterojunction photocatalysts exhibit remarkable photon-to-thermal conversion and can attain a heating rate as great as 160.64 °C/s under solar irradiation with average light intensity of 365 mW/cm 2 , which is significantly greater than the 40.94 °C/s heating rate attained by pristine Bi 4 TaO 8 Cl photocatalysts. The proposed photothermal catalyst overcomes the high CO production obtained via conventional Bi 4 TaO 8 Cl photocatalysts, and thereby obtains high liquid alcohol (methanol and ethanol) selectivities of 92% and 76% under broadband and strictly visible light irradiation, respectively, for CO 2 -H 2 O mixtures in a flow reactor at a temperature of 200 °C. Analyses demonstrate that the superior CO 2 reduction performance of the Bi 4 TaO 8 Cl/Bi heterojunction photocatalysts can be attributed to increased optical absorption, bidirectional charge transfer across the Bi 4 TaO 8 Cl/Bi interface, and the surface plasma resonance of the Bi nanoparticles. Accordingly, this work provides a novel strategy for the production of value-added liquid fuels in future CO 2 conversion processes.