Ultrasound-driven reduction of Cr(VI) using hydrothermally synthesized CuInS2 nanoparticles

Ultrasonic catalytic technology has emerged as a promising approach for efficiently addressing water pollution. This work demonstrates the one-step hydrothermal synthesis of narrow-bandgap CuInS 2 nanocatalysts and their application in the sonocatalytic reduction of toxic Cr(VI). The hydrothermal temperature was identified as a critical factor governing both morphology and catalytic performance. Among all synthesized samples, the catalyst prepared at 200 °C exhibited the highest activity. Under optimized reaction conditions, 91.32 % of Cr(VI) was reduced within 60 min. The specific parameters were: 5 mg/L Cr(VI), 50 mg catalyst, pH 6, and 216 W ultrasonic power. Notably, the catalyst also demonstrated excellent reduction performance without requiring pH adjustment. The catalyst also displayed excellent stability, maintaining 74.61 % removal efficiency after four consecutive cycles. Radical trapping experiments have revealed that electrons (e − ) act as the predominant active species in the reduction process. This is the first report on the sonocatalytic application of CuInS 2 for Cr(VI) remediation, highlighting its potential for practical environmental treatment. We synthesized narrow-bandgap CuInS 2 nanocatalysts using a one-step hydrothermal method and applied them to reduce toxic Cr(VI). The hydrothermal temperature was crucial for morphology and catalytic performance. At 200 °C, the catalysts achieved a 91.32 % degradation efficiency for 5 mg/L Cr(VI) and maintained 74.61 % efficiency after four cycles. This is the first report of CuInS 2 in sonocatalytic Cr(VI) remediation, highlighting its potential for environmental treatment. • A straightforward solvothermal method allows the synthesis of CIS. • By varying the synthesis temperature, samples exhibiting diverse morphologies and band gaps were obtained. • The highest sonocatalytic degradation rate of Cr(VI) was 91.32 %. • Excellent reduction performance without requiring pH adjustment. • Adequate stability and generalizability of the subject.