Two-dimensional nanomaterials for photocatalytic CO₂ reduction to solar fuels

As a “kill two birds with one stone” approach, photocatalytic CO₂ reduction to solar fuels can save supplying energy and simultaneously protect our environment. Specifically, the use of CO₂ as the starting carbon source can help with the required emission cuts. Meanwhile, it directly generates short-chain hydrocarbon products such as CH₄, CH₃OH, C₂H₆ and so on, which can serve as a renewable energy source (solar fuels) to alleviate the increasingly tense energy crisis. Two-dimensional (2D) nanomaterials possess several extraordinary advantages, including large surface-to-volume ratio, abundant active sites, atomic thickness, and a high fraction of coordinated unsaturated surface sites, making them promising candidates with high photocatalytic activity for CO₂ reduction. This review summarizes a series of typical 2D nanomaterials for photocatalytic CO₂ conversion, such as graphene-based photocatalysts, graphitic carbon nitride-based photocatalysts, 2D metal oxide-based photocatalysts, 2D metal chalcogenide-based photocatalysts, 2D metal oxyhalide-based photocatalysts, and layered double hydroxide-based photocatalysts. Furthermore, based on the characteristics of 2D materials and the current status of research on photocatalytic CO₂ reduction, the challenges and opportunities of 2D materials as prospective photocatalysts for CO₂ reduction will also be discussed.