Photocatalytic CO2 conversion: What can we learn from conventional COx hydrogenation?

Solar-driven reduction of CO2 into fuels/feedstocks is a promising strategy for addressing energy and CO2 emission issues. Despite great research efforts, it still remains a grand challenge to achieve efficient and highly selective reduction of CO2 owing to the large bond energy of CO2 and the diversity of reduction products. In addition to the control of light harvesting and charge transfer like photocatalytic water splitting, the design of catalytically active sites is highly important to promote CO2 reduction activity and selectivity (e.g., C–C coupling). In fact, we can learn a lot from conventional CO2 hydrogenation and syngas conversion in terms of active site design. In this article, we demonstrate how to design catalytically active sites for efficient and highly selective photocatalytic reduction of CO2 by sorting out the rules from the existing research on conventional COx hydrogenation, with a focus on enhancing C=O activation and C–C coupling to form value-added products. This article aims to highlight the challenges in the field of photocatalytic CO2 conversion and the connection of photocatalysis with conventional catalytic systems, providing the readers the opportunities to join the research.