Recent Progress in the Photocatalytic Reduction of Carbon Dioxide

Elimination or reduction of CO₂ in the atmosphere is a serious problem faced by humankind, and it has become imperative for chemists to find ways of transforming undesirable CO₂ to useful chemicals. One of the best means is the use of solar energy for the photochemical reduction of CO₂. In spite of considerable efforts, discovery of stable photocatalysts which work in the absence of scavengers has remained a challenge although encouraging results have been obtained in the photocatalytic reduction of CO₂ in both gas and liquid phases. Semiconductor-based catalysts, multicomponent semiconductors, metal-organic frameworks (MOFs), and dyes as well as composites involving novel composite materials containing C₃N₄ and MoS₂ have been employed for the photoreduction process. Semiconductor heterostructures, especially those containing bimetallic alloys as well as chemical modification of oxides and other materials with aliovalent anion substitution (N³⁻ and F⁻ in place of O²⁻), remain worthwhile efforts. In this article, we provide a brief perspective of the present status of photocatalytic reduction of CO₂ in both liquid and gas phases.