Synthesis of noble‐metal‐free ternary K7HNb6O19/Cd0.5Zn0.5S/g‐C3N4 tandem heterojunctions for efficient photocatalytic performance under visible light.

Exploring noble‐metal‐free, highly active and durable catalysts is vital to get to grips with the energy and environmental issues. Herein, we first dexterously design and synthesize a class of ternary Nb6/CZS/g‐CN photocatalysts for the removal of hexavalent chromium Cr (VI) and organic dye pollutant (MO) from wastewater under visible‐light irradiation. A heterojunction Nb6–1/CZS/g‐CN loaded with 0.01 g K7HNb6O19 showed excellent photocatalytic performance, with the MO photodegradation efficiency of 94% in 1 h and the Cr (VI) (150 mg/l) photoreduction efficiency as high as 91% in 2 hr. The main active species were deemed to be O2.‐. Additionally, the as‐prepared ternary heterojunction exhibits superior hydrogen evolution reaction (HER) rate. A heterojunction Nb6–4/CZS/g‐CN loaded with 0.5 g K7HNb6O19 exhibited the highest H2 evolution rate as high as 1777.86 μmol h−1 g−1 under visible‐light illumination, which is increased to 5.7 and 2.7 times that of bare CZS and biphase heterojunction CZS/g‐CN. These findings afford a new class of promising low‐cost photocatalyst bodying for its huge potential value in sustainable energy development and wastewater treatment. [ABSTRACT FROM AUTHOR]