In-situ construct CuInS2/Bi/Bi2MoO6 S-scheme/Schottky dual heterojunctions catalyst for enhanced photocatalytic degradation of diclofenac sodium

Abstract

In this paper, the S-scheme/Schottky heterojunction photocatalyst (CuInS₂/Bi/Bi₂MoO₆, CIS/Bi/BMO) was successfully constructed via a facile in-situ solvothermal method, aimed at enhancing its photocatalytic performance. The results of the study on the photocatalytic degradation of diclofenac sodium (DCF) under simulated solar light irradiation revealed that the as-prepared composite exhibited remarkable catalytic efficiency in comparison to the pristine Bi₂MoO₆ and CuInS₂. The plasmonic bismuth (Bi) was formed during the solvothermal process. Subsequently, CuInS₂ and Bi were grown on the surface of Bi₂MoO₆ leading to forming CIS/BMO S-scheme heterojunction, along with a Schottky junction between Bi and Bi₂MoO₆. The use of ethylene glycol as a support was the main reason for the significant improvement in photocatalytic efficiency in the degradation of DCF. Moreover, the probable photocatalytic mechanisms for the degradation of DCF had been proposed based on the active species quenching experiments. The eleven degradation products were detected by HPLC-MS, and the degradation reaction pathway of DCF was deduced. Additionally, the CIS/Bi/BMO photocatalyst exhibited a consistently high removal rate after four cycles. This study proposes a new strategy for designing efficient S-scheme/Schottky heterojunction photocatalysts for solar energy conversion.

Keywords: CuInS(2)/Bi/Bi(2)MoO(6); Diclofenac sodium; Photocatalysis; S-Scheme/Schottky dual heterojunctions.