【Frontiers of HaiChuan Chemical Technology】Amazing! Significant progress has been made in the field of photocatalytic hydrogen isomerization at the Dalian Institute of Chemical Physics, enabling hydrogen isomerization at room temperature

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Recently, the team led by Researcher Wang Feng and Associate Researcher Luo Nengchao from the Bioenergy Chemicals Research Group (DNL0603 group) in the Bioenergy Research Department of the Dalian Institute of Chemical Physics, together with Researchers Zhang Fuxiang, Xiao Jianping, Li Rengui, Liu Wei, and Chen Ruotian from the same institute, Professor Paolo Fornasiero from the University of Trieste in Italy, and Professor Wang Guoxiong from Fudan University, made significant progress in the field of photocatalytic hydrogen cleavage, achieving hydrogen cleavage at room temperature. Hydrogenation reactions are one of the important reactions in the chemical industry; approximately 25% of chemical reaction processes involve at least one hydrogenation step. One of the key aspects of hydrogenation reactions is hydrogen activation, which includes two mechanisms: homolysis and heterolysis. Among them, hydrogen isomerization produces polar hydrogen species, which are highly reactive and exhibit selective hydrogenation of polar functional groups. However, hydrogen isomerization generally requires high reaction temperatures, and the low reaction rate of hydrogen isomerization due to the low concentration of reactive sites often makes it the rate-determining step in hydrogenation reactions. The active sites for hydrogen isomerization include various types, but their essential structural feature is the presence of positively and negatively charged centers that are spatially adjacent (on the sub-nanometer scale). In this work, Wang Feng’s team built upon the previously developed photocatalytic conversion method that utilizes separately generated photoelectrons and holes to drive half-reactions (Nature Energy, 2019 ； Nature Catal., 2020 ； J. Am. Chem. Soc., 2022 ； Joule，2023 ； Angew. Chem. Int. Ed., 2023 ； Nature Synth., 2024 ； J. Am. Chem. Soc., 2024 ； Angew. Chem. Int. Ed., 2025) proposes the use of photo-generated electrons and holes to create spatially adjacent positive and negative charge centers, thereby enabling hydrogen cleavage at room temperature. This research overcame the key scientific challenge of creating spatially adjacent electron and hole bound states, effectively avoiding electron-hole recombination due to spatial proximity while utilizing electron-hole pairs to catalyze hydrogen cleavage. Using gold/titanium dioxide (Au/TiO2) as a model catalyst, researchers stimulated TiO2 with ultraviolet light; the findings indicate that the electrons generated by this light stimulation can migrate to the Au nanoparticles and become trapped there ； At the same time, due to the defect states composed of Au-O-Ti at the interface between Au nanoparticles and TiO2, the photogenerated holes are trapped at this interface. Studies have found that due to holes and electrons being located at the Au-O-Ti interface and Au nanoparticles respectively, spatially adjacent bound electron-hole pairs are formed. The thermocatalytic mechanism of hydrogen cleavage occurring simultaneously with Au/TiO2 at room temperature, combined with the photocatalytic mechanism of hydrogen cleavage on Au/TiO2, led researchers to observe that the reactivity of this reaction first decreased and then increased linearly as the light intensity increased. Furthermore, the team applied the aforementioned photocatalytic hydrogen cleavage method to the reduction of carbon dioxide (CO2), achieving a one-pass conversion rate of nearly 100% for CO2 in a photocatalytic fixed-bed reactor; the main product was ethane, with a selectivity of over 99%, and the stability of the photocatalytic CO2 hydrogenation process exceeded 1500 hours. By connecting the ethane dehydrogenation to ethylene production unit, the team achieved the conversion of CO2 into ethylene through hydrogenation, with a one-pass yield of over 99%. This photocatalytic hydrogen cleavage method can be extended to systems such as Au/N-TiO2, Au/CeO2, and Au/BiVO4; it can also be used to produce ethane via the hydrogenation of CO2 using sunlight, with a selectivity of 90%.