Catalyst-free photochemical CO₂ hydrogenation to CO and CH₄ conversion to C₂H₆

Direct utilization of high-energy photons to drive chemical reactions presents a promising approach for the achievement of green reaction process. Herein, we developed a simple photochemical route that utilized 172 nm vacuum ultraviolet (VUV) photons as drivers for CO₂ hydrogenation to CO and transformation of CH₄ to H₂ and C₂H₆. It was demonstrated that the reactions could proceed efficiently at catalyst-free and ambient conditions, and water could further promote the transformation of CH₄. The reaction mechanism was proposed on the basis of control experiments. This study provides a green alternative to conventional catalytic processes for important reactions, i.e., CO₂ hydrogenation or CH₄ conversions triggered by high-energy photons under ambient conditions, which have promising potential in applications due to some obvious advantages.