Synergistic Coupling of Photocatalysis and Thermocatalysis for Efficient CO₂ Conversion by Direct Z-Scheme WO₃/WS₂

Photothermal CO2 reduction using H2O combined with photocatalysis-driven H2O splitting combined with thermal catalysis-supported CO2 reduction has attracted rapid interest in artificial synthesis of solar fuel. With respect to extremely efficient photothermal catalysis, the photothermal impact of TMDCs (Transition Metal Dichalcogenides) facilitates CO2 reduction by activating lattice oxygen in oxide to enhance H2O oxidation. However, the fixed band gap of single photocatalyst is limited. The purpose of this work is to expand the band gap and improve the redox capacity. Hollow boxwood ball-like WO3/WS2 Z-scheme heterojunctions were prepared and used for photothermal catalytic CO2 reduction. DFT calculations and UV-Vis spectra show LSPR effect in WOS heterojunctions, and the optical response extends to near infrared region. By comparison, the photothermal catalytic reduction of WO3/WS2 (9.717 mu mol) by CO2 at 513 K is higher than that at 298 K (1.198 mu mol) by a factor of 8. The formation of Z-scheme heterojunction promotes rapid carrier transfer and lowers the reaction energy barrier. As well as the hollow structure improves light utilization and increases the interfacial area and number of active sites. In addition, the WO3/WS2 heterostructure utilizes its unique LSPR effect to generate heat through the photothermal effect, which can also promote molecular activation. This work reveals the important role of the LSPR effect in photothermal catalysis and demonstrates a TMDCs-based photothermal-driven catalysts, which presents a promising approach for designing of photothermal catalytic CO2 reduction.