In situ prepared 2D/2D BiOBr/ Cd-TCPP MOF S-scheme heterojunction for enhancing photothermal catalytic CO₂ reduction

Carbon dioxide to high value-added fuel or chemicals by photo-thermal synergistic catalysis has opened up a new route to solve the issues in carbon emission and energy shortage. By now, its efficiency is a bottleneck to be broken through. In this study, we in-situ synthesized an S-scheme heterostructure composed of 2D/2D BiOBr/Cd-TCPP MOF. The inclusion of π-π stacking interactions within the porphyrin MOF structure facilitates non-radiative transitions to enhance the photothermal catalytic efficiency in reducing CO₂ synergistically. The S-scheme charge transfer mechanism explored with DFT, XPS, and EPR analyses demonstrated improvement of redox capabilities and effective suppression of electron-hole recombination in such a S-scheme heterojunction. Experimental results revealed the BiOBr/CdMOF catalyst achieving carbon monoxide yields of 167.02 µmol·g⁻¹ and 329.91 µmol·g⁻¹ at photo and photothermal conditions in 5 h, respectively. Both yields are substantially higher than 27.46 µmol·g⁻¹ of pristine BiOBr. The results prove remarkable photothermal synergistic performance of this catalyst and provide an innovative idea for developing new photothermal catalyst based on S-type heterojunction structure.