Electrosynthesis of Syngas via the Co-Reduction of CO2 and H2O

The traditional synthesis of syngas, a mixture of CO and H2, relies on the reverse water gas shift reaction at high temperature and thus consumes considerable energy and resources. In this regard, the electrochemical conversion of CO2-H2O to CO-H2 provides an emerging alternative technique to conquer these shortages. This short review highlights the recent advances and future trends in the electrocatalytic transformation of CO2 and H2O to syngas with a tunable H2:CO ratio. We summarize the latest advances in metals, metal oxides and chalcogenides, metal complex catalysts, single-atom catalysts, and metal-free catalysts with an emphasis on controlling the CO:H2 ratio, which is vital for downstream Fischer-Tropsch process synthesis. Then we introduce versatile methods to improve the production efficiency of syngas by alternative anode reactions and advanced technologies (e.g., gas diffusion electrode-based, flow, solid oxide electrolytic cells). Finally, we provide an outlook on the current challenges and promising opportunities in the field of syngas synthesis.