In Situ Confined Growth of Co₃O₄–TiO₂/C S-Scheme Nanoparticle Heterojunction for Boosted Photocatalytic CO₂ Reduction

An S-scheme nanoparticle heterojunction of Co 3 O 4 –TiO 2 /C has been designed to enhance CO 2 adsorption and accelerate interfacial electron transfer, thereby boosting photocatalytic CO 2 reduction. Co 2+ -loaded MXene nanosheets are used as a single precursor for in situ confined growth of Co 3 O 4 –TiO 2 /C. The in situ confined growth of the nanoparticle heterojunction enables good particle dispersion and a small particle size, which makes the surface and active sites highly exposed and accessible for CO 2 molecules. In addition, p-type Co 3 O 4 and n-type TiO 2 build an S-scheme heterojunction. As a result, the Co 3 O 4 –TiO 2 /C nanoparticle heterojunction exhibits a higher specific surface area, larger CO 2 adsorption capacity, and faster charge transfer compared to pure Co 3 O 4 and TiO 2 /C. The gas generation rate over Co 3 O 4 –TiO 2 /C is as high as 33.21 mmol g –1 h –1, which is 8.34 and 1.69 times higher than that of pure TiO 2 /C and Co 3 O 4, respectively. 3 h photocatalysis affords a remarkable turnover number of 15.53 that is comparable to state-of-the-art photocatalysts.