Construction of 0D Ti₃C₂O₂/2D black phosphorus S-scheme heterostructure for photocatalytic CO₂ reduction

Photocatalytic carbon dioxide reduction reactions (CO₂RR) have aroused great interest in the field of carbon neutrality and clean energy production. CH₄ is an ideal product of CO₂RR as a clean-burning fuel and the major component of natural gas. However, the efficient separation of photogenerated carriers and the effective activation of CO₂ molecules are critical issues of CO₂ reduction catalysts. Based on density functional theory, we investigated the catalytic performance for the 0D/2D heterostructure composed of Ti₃C₂O₂ quantum dots (T3QD) and black phosphorene (BP). The contact between the two components in 0D/2D heterostructure induced a built-in electric field and caused band bending, forming an S-scheme transfer mechanism that facilitated efficient charge separation while maintaining a high reactive potential. The edge site of T3QD has excellent catalytic activity to activate CO₂ molecules and form key intermediates for eventual reduction to CH₄. This work provides theoretical guidance for designing 0D MXene and constructing 0D/2D heterojunctions for photocatalytic applications.