Nanostructured TiO2 for light-driven CO2 conversion into solar fuels

Energy shortages and global warming have become two major issues closely associated with the tremendous consumption of non-renewable fossil fuels. As a sustainable and economical route, photocatalytic reduction of CO2 conversion, the so-called artificial photosynthesis, provides an alluring strategy to realize the twofold benefits with respect to closing carbon cycle and producing renewable fuels/chemicals, thereby solving the above issues. TiO2 photocatalysts have attracted widespread attention in CO2 reduction reactions owing to their low cost, high stability, and environmental safety. Nevertheless, the limited absorption ability in the visible light range and fast recombination of photogenerated electrons and holes are the two main drawbacks impeding practical applications. This minireview summarizes the fabrication methodologies of nanostructured TiO2 (especially focused on the 1D, 2D, and 3D nanostructures), discusses the fundamentals of photocatalytic CO2 reduction to value-added chemicals, and draws a comparison of photocatalytic performances from modified TiO2 nanostructures. In further contexts, the opportunities and challenges for nanostructured TiO2 based materials on CO2 conversion are proposed.