Surface hydrogen-bonded network enhances radical-assisted CO₂ reduction to C₂H₄

Non-thermal plasma (NTP) offers a promising route for direct CO₂ reduction with H₂O under ambient conditions, whereas the non-selective reactivity of gaseous ·H and ·OH radicals from H₂O dissociation severely limits selectivity toward value-added products, such as C₂H₄. Here, we synthesized a ternary metal-cluster organic framework (CeHfZr) that adsorbed H₂O to form a surface hydrogen-bonded network and utilized high-energy electrons to generate solvated ·H and ·OH radicals in situ, effectively promoting CO₂ conversion to C₂H₄. This catalyst achieved a C₂H₄ production rate of 164.6 μmol/(g·h) under 20% CO₂, which displayed a 15-fold enhancement over Ce, with a sustained stability over 180 min. In-situ IR spectroscopy and mechanistic analysis demonstrated that the hydrogen-bonded H₂O network on CeHfZr enabled in situ ionization to produce ·H and ·OH radicals. The ·OH radicals eliminated deep-seated carbon deposits to regenerate active sites, together with the ·H radicals underwent rapid conversion to adsorbed *H through proton transfer along the hydrogen-bonded network, thereby driving C-C coupling for enhanced C₂H₄ production. This research offers insights into the rational design of catalysts for non-thermal plasma-driven CO₂ reduction to C₂H₄.