Visible light CrO42− reduction using the new CuAlO2/CdS hetero-system

► The work deals with the chromium reduction over CuAlO2/CdS hetero-system. ► The conduction band of CdS (−1.08 V) is more negative than the CrO42−/Cr3+ level. ► The sensitizer CuAlO2 has been synthesized by sol-gel. ► The Cr(VI) reduction follows a pseudo first order kinetic with of salicylic acid.