Advancements and Challenges in Reductive Conversion of Carbon Dioxide via Thermo-/Photocatalysis.

Carbon dioxide (CO 2 ) is the major greenhouse gas and also an abundant and renewable carbon resource. Therefore, its chemical conversion and utilization are of great attraction for sustainable development. Especially, reductive conversion of CO 2 with energy input has become a current hotspot due to its ability to access fuels and various important chemicals. Nowadays, the controllable CO 2 hydrogenation to formic acid and alcohols using sustainable H 2 resources has been regarded as an appealing solution to hydrogen storage and CO 2 accumulation. In addition, photocatalytic CO 2 reduction to CO also provides a potential way to utilize this greenhouse gas efficiently. Besides direct CO 2 hydrogenation, CO 2 reductive functionalization integrates CO 2 reduction with subsequent C-X (X = N, S, C, O) bond formation and indirect transformation strategies, enlarging the diverse products derived from CO 2 and promoting CO 2 reductive conversion into a new stage. In this Perspective, the progress and challenges of CO 2 reductive conversion, including hydrogenation, reductive functionalization, photocatalytic reduction, and photocatalytic reductive functionalization are summarized and discussed along with the key issues and future trends/directions in this field. We hope this Perspective can evoke intense interest and inspire much innovation in the promise of CO 2 valorization.