Insight into ZnO/carbon hybrid materials for photocatalytic reduction of CO2: An in-depth review

Extensive burning of fossil fuels to fulfill the intensifying demands of energy has led to raising the concentration of carbon dioxide in atmosphere, which is a major component responsible for global warming. Imitating the natural photosynthesis, photoreduction of CO2 seems to be one of the most promising solutions to this critical problem. Among the different photocatalysts, ZnO had been thoroughly examined for CO2 reduction owing to its low cost and eco-friendliness. Combining ZnO with carbon-based nanomaterials is being progressively investigated to improve the photocatalytic efficiency. This article is organized to explore the latest advancements in ZnO/carbon nanocomposites for photocatalytic CO2 reduction systems. The article begins with the fundamentals of photocatalysis, and the basic mechanism of CO2 reduction over semiconductor materials is also reviewed. Then, it surveys literature and underlines the recent developments of ZnO/carbon-based hybrid nanomaterials, covering activated carbon, graphene-based materials, carbon nanotubes, carbon dots and recently developed morphologies. More specifically, synthesis routes and mechanisms of CO2 reduction enhancement are thoroughly discussed. Finally, a summary along with some new valuable recommendations are also presented.