Rationally designed S-scheme heterojunction of C3N4/Bi2MoO6/carbon fiber cloth as a recyclable, macroscopic and efficient photocatalyst for wastewater treatment

Abstract

Developing efficient photocatalysts with ease of recovery is highly desirable for actual wastewater purification. Herein, S-scheme 2D-C3N4/2D-Bi2MoO6 heterojunctions on carbon fiber (CF) cloth were synthesized via a facile thermal condensation-solvothermal method. The designed CF/C3N4/Bi2MoO6 cloth woven with carbon fibers covered by interlaced two-dimensional nanosheets was endowed with boosted charge transfer efficiency at the interfacial heterojunction and the maximum redox potential, which favors the production of more active radicals. As a result, the photocatalytic activity for degrading the antibiotic (86% TC) or reducing the heavy metal ion (80% Cr(VI)) has been improved, in comparison with CF/C3N4 (44% TC, 12% Cr(VI)) and CF/Bi2MoO6 (76% TC, 66% Cr(VI)) cloth. Moreover, the flexible, macroscopic filter-membrane-shaped morphology endowed the catalyst with excellent recyclability that can be easily separated from wastewater and a highly stable photocatalytic performance that more than 98% of the initial photocatalytic activity is maintained after six successive cycles. More significantly, the well-designed cloth-shaped catalyst can efficiently treat the flowing sewage. Together with the analyses of band structure and DFT calculations, a potential S-scheme mechanism was confirmed. Moreover, the toxicity evaluation confirmed the efficient toxicity elimination of TC in the CF/C3N4/Bi2MoO6/visible light system. All the results show that the as-prepared photocatalyst has excellent photocatalytic performance and fascinating recyclability, suggesting great potential for wastewater treatment.