Facile electrospinning synthesis of S-scheme heterojunction CoTiO3/g-C3N4 nanofiber with enhanced visible light photocatalytic activity

Photocatalysts featuring S-scheme heterojunctions offer considerable potential for both the photocatalytic CO 2 conversion and the degradation of antibiotics, providing practical solutions for energy crises and environmental challenges. In this work, 1D/2D CoTiO 3 /g-C 3 N 4 (CTO/CN) S-scheme heterojunction is synthesized through electrospinning and calcination . The close interweaving of g-C 3 N 4 nanosheets around CoTiO 3 nanofibers creates ample contact areas and active sites, resulting in exceptional photocatalytic CO production capability. The optimal mass ratio of CoTiO 3 to g-C 3 N 4 is 2%, and the CO and CH 4 yields are 46.5 and 0.825 μmol g -1 h -1 . Moreover, comparing with monomeric g-C 3 N 4 , this composite achieves a better CO yield with 43.5 times and displays an impressive product selectivity of 98.3% for CO 2 -CO photoreduction . In addition, the 2% CTO/CN photocatalyst demonstrates outstanding photocatalytic degradation efficiency, with degradation rates of 95.88%, 95.53%, and 71.23% for tetracycline hydrochloride , oxytetracycline , and ofloxacin , respectively. These enhanced photocatalytic properties are attributed to the S-scheme system constructed by CoTiO 3 with g-C 3 N 4 , maintaining strong oxidation-reduction capabilities while efficiently segregating photogenerated charges, with the existence of S-scheme heterojunction confirmed through various analyses. Furthermore, in situ studies and 13 C calibration experiments reveal that CO and CH 4 originate from the photocatalytic CO 2 conversion, further highlighting the potential of this work in advancing CO 2 photoreduction . This study offers novel insights into designing effective S-scheme heterojunction photocatalysts for practical applications to address environmental and energy challenges.