Emerging innovations and breakthroughs in dual hydrogen production

In recent years, dual hydrogen (H₂) production has been an efficient electrocatalytic process in which H₂ is generated at the cathode through a half-reaction in water electrolysis and at the anode through the oxidation of organic small molecules. This new approach has been paid much more attention due to succeeding in avoiding high energy consumption, safety risks from the mixture of H₂ and O₂, and the low economic value of byproducts, all of which are significant challenges for traditional water electrolysis particularly at high current densities. Therefore, it is urgently needed to systematically review the advanced development of dual H₂ production. In this review, firstly, we summarize the two mechanisms of dual H₂ production: cleaving C–H to form H₂ and cleaving N–H to form H₂. Secondly, we comprehensively introduce the utilization of specific anode H₂ evolution materials under these two mechanisms of dual H₂ production, as well as a series of design strategies such as specific optimization of catalyst materials. Last but not least, we present the outlooks of dual H₂ production, which will provide a preliminary theoretical basis and new ideas for the development of low-cost, high-performance, long-term stable new materials and novel thinking for dual H₂ production.