Fabrication of Z-scheme Cd0.85Zn0.15S/Co9S8 dual-functional photocatalyst for effective hydrogen evolution and organic pollutant degradation

Abstract

Abstract A Z-scheme Cd0.85Zn0.15S/Co9S8 (CZS-CS) photocatalyst was reasonably fabricated by a simple solvothermal method for the effective visible-light-driven H2 evolution and organic pollutants degradation. The precise construction of the CZS-CS composites provided an efficient heterogeneous contact interface and abundant reaction sites for the proposed photocatalytic reaction. The homogeneous Co9S8 nanocrystals were uniformly wrapped on the surface of Cd0.85Zn0.15S nanorods, forming an intimate-contact interface, markedly contributed to the light collection and effectively inhibited the charge-carrier recombination. The optimized CZS-CS-15 composites exhibited a special H2 production rate reaching 19.15 mmol·h−1·g−1, roughly 1915 and 4.5 times of pure Co9S8 and Cd0.85Zn0.15S samples and 85% of tetracycline (TC) molecule within 15 min was degraded. Furthermore, trapping experiments confirmed that h+ was the main active species for TC photodegradation. Moreover, the obtained photocatalysts manifested stability without apparent activity declines during the proposed reactions. Finally, the Z-scheme photocatalytic mechanism was verified to illustrate the characteristics of efficient charge transfer and high redox ability. This study provided a rational and learnable strategy for designing dual-functional Z-scheme heterojunction photocatalysts.