Construction of Co9Se8/TiO2 S-scheme heterojunction photocatalyst for efficient hydrogen production

Construction of S-scheme heterostructure is the focus of catalyst modification in the field of photocatalysis. In this work, the nanosized Co9Se8 and TiO2 particles were fabricated via a simple hydrothermal process. A series of Co9Se8/TiO2 heterojunctions were subsequently constructed through a physical solvent evaporation strategy. The photocatalytic H2 evolution experiment shows that the H2 evolution rate can reach 8282.7 & mu;mol & BULL;g- 1 & BULL;h-1 over 15 %-Co9Se8/TiO2 under 300 W Xe lamp irradiation using 20 % triethanolamine (TEOA) as the sacrifice agent, which is 29.9-fold and 95.8-fold higher than that of pristine TiO2 (277.3 & mu;mol & BULL;g- 1 & BULL;h- 1) and Co9Se8 (86.5 & mu;mol & BULL;g- 1 & BULL;h-1), respectively. The enhanced photocatalytic performance is primarily attributed to the improved light absorption ability and the formed S-scheme heterojunctions between TiO2 and Co9Se8, which could efficiently accelerate the separation and migration of photo-induced charges. Furthermore, the powerful electrons and holes are preserved, thereby earned robust redox ability to prompt H2 evolution reaction. This work affords a feasible approach to obtain S-scheme photocatalysts for effectively converting solar energy to H2.

Automated summary

In this study, nanosized Co9Se8 and TiO2 particles were fabricated using a hydrothermal process, followed by the construction of various Co9Se8/TiO2 heterojunctions using a physical solvent evaporation strategy. The photocatalytic H2 evolution experiment demonstrated that the H2 evolution rate over 15%-Co9Se8/TiO2 reached 8282.7 μmol∙g-1∙h-1 under 300 W Xe lamp irradiation, using 20% triethanolamine (TEOA) as the sacrifice agent. This rate was 29.9-fold and 95.8-fold higher than that of pristine TiO2 and Co9Se8, respectively. The enhanced photocatalytic performance was attributed to improved light absorption ability and the formation of S-scheme heterojunctions, which promoted the separation and migration of photo-induced charges.