Multifunctional Ni–Mg bimetal-activated Zn(O,S) for hydrogen generation and environmental remediation with simulated solar-light irradiation

Abstract

A Ni–Mg bimetal-doped Zn(O,S) photocatalyst has been synthesized, characterized, and tested for several photocatalytic applications. The hydrogen generation reaction, hydrogenation reaction for chemical transformation, detoxification of hexavalent chromium, and mixed dye (MB + RhB + MO) degradation under simulated solar-light illumination were confirmed. The essential characterization results indicated improved oxygen vacancy sites on the catalyst with enhanced photoresponse, better photocarrier separation, and facile charge transfer properties. A typical catalyst, NMZ-S10, was evaluated with a 1000-cycle CV test to demonstrate its long-term use for industrial application. Stable reusability experiments for the HER, PHR, PHC reaction, and PDM also supported the long-term application. The photocatalytic HER of NMZ-S10 could evolve hydrogen at a rate of 4000 μmol g⁻¹ h⁻¹. 30 ppm azobenzene-to-aniline conversion was completely done in 2 h of reaction. Detoxification of 30 ppm hexavalent chromium was conducted in 70 min of reaction. Finally, 10.5 ppm MB–RhB–MO mixed dye degradation was carried out in 1 h of reaction. The as-synthesized NMZ-S10 catalyst has demonstrated its capability to overcome energy and environmental issues promisingly. The great photocatalytic activities are discussed and elucidated with a plausible mechanism to rationalize the superb catalytic performance.