Recent Advances in TiO-Based Photocatalysts for Reduction of CO to Fuels.

Titanium dioxide (TiO) has attracted increasing attention as a candidate for the photocatalytic reduction of carbon dioxide (CO) to convert anthropogenic CO gas into fuels combined with storage of intermittent and renewable solar energy in forms of chemical bonds for closing the carbon cycle. However, pristine TiO possesses a large band gap (3.2 eV), fast recombination of electrons and holes, and low selectivity for the photoreduction of CO. Recently, considerable progress has been made in the improvement of the performance of TiO photocatalysts for CO reduction. In this review, we first discuss the fundamentals of and challenges in CO photoreduction on TiO-based catalysts. Next, the recently emerging progress and advances in TiO nanostructured and hybrid materials for overcoming the mentioned obstacles to achieve high light-harvesting capability, improved adsorption and activation of CO, excellent photocatalytic activity, the ability to impede the recombination of electrons-holes pairs, and efficient suppression of hydrogen evolution are discussed. In addition, approaches and strategies for improvements in TiO-based photocatalysts and their working mechanisms are thoroughly summarized and analyzed. Lastly, the current challenges and prospects of CO photocatalytic reactions on TiO-based catalysts are also presented.