Visible-light-driven CO2 photoreduction to solar fuels over a Ni/Cu-loaded Bi2ZnTiO6/g-C3N4 0D/3D/2D QDs Schottky/Z-scheme ternary heterojunction photocatalyst

Currently, the increasing concentration of carbon dioxide (CO 2 ) pollutants in the Earth’s atmosphere due to the expansion of factories and vehicles has caused destructive effects, including an increase in the greenhouse effect, long-term droughts, insufficient rainfall, melting polar ice, and climate change. The various methods are available for removing carbon. Photocatalytic processes have emerged as promising and sustainable approaches for CO 2 conversion because they don’t make harmful byproducts, affect most contaminants, do not have any detrimental effects on the environment, don’t need expensive, complicated equipment, are readily recoverable, recover, and use again. Perovskite is a novel kind of photocatalyst that exhibits excellent photocatalytic performance. Photocatalysts with more than one structure are better at covering a bigger area. Perovskite photocatalysts can reduce pollutants more quickly and better than other mono-photocatalysts. When exposed to visible light, this investigation intends to make a modern perovskite photocatalyst that exhibits enhanced performance and can convert carbon dioxide into solar fuels. To achieve this, g-C 3 N 4 (gCN), a non-metallic co-photocatalyst; Bi 2 ZnTiO 6 (BZTO), a double perovskite; and zero valent nickel/copper (Ni/Cu) nanoparticles, a metallic co-photocatalyst, were synthesized. XRD, SEM, EDX/mapping, UV–vis, DRS, and PL experiments were employed to look at the phase, crystallographic, structural, and photocatalytic properties. The performance of the Ni/Cu-loaded Bi 2 ZnTiO 6 perovskite/g-C 3 N 4 0D/3D/2D QDs Schottky/Z-scheme ternary heterojunction nanocomposite was optimized and improved using Taguchi’s experimental design. The temperature of the reaction, how rapidly it was agitated, how long it took, how much CO 2 and photocatalyst were present, visible irradiation intensity, interval between photoreduction site and light source, and the pH of the reaction are all critical parameters. To achieve the best conditions according to the Taguchi method, the solution should have a reaction medium pH of 5.0, a temperature of 25 °C, a mixing rate of 200 rpm, a photoreduction time of 300 min, a photocatalyst dosage of 1.0 g/l, a CO 2 concentration of 400 mg L −1 , a light intensity of 70 W, distance between light source and aqueous solution. The Ni/Cu-loaded Bi 2 ZnTiO 6 /g-C 3 N 4 Schottky/Z-scheme ternary heterojunction nanocomposite transformed the CO 2 with a proficiency rate of 1727 μmol g −1 h −1 (total CO 2 conversion efficiency 95%) into the main solar fuels of methane (CH 4 ) gas with a productivity ratio of 863.5 μmol g −1 h −1 (selectivity efficiency 50%) and methanol (CH 3 OH) with a productivity rate of 690.8 μmol g −1 h −1 (selectivity efficiency 40%). Additionally, the Ni/Cu-loaded Bi 2 ZnTiO 6 /g-C 3 N 4 ternary nanocomposite maintained its structure and could be utilized over and over again, even after five cycles of continuous use.