Photo‐Initiated Reduction of CO₂ by H₂ on Silica Surface

Abstract

The reduction of CO is a promising route to produce valuable chemicals or fuels and create C-neutral resource cycles. Many different approaches to CO reduction have been investigated, but the ability of vacuum UV (VUV) irradiation to cleave C-O bonds has remained largely unexplored for use in processes that convert CO into useful products. Compared with other photo-driven CO conversion processes, VUV-initiated CO reduction can achieve much greater conversion under common photochemical reaction conditions when H and non-reducible oxides are present. Infrared spectroscopy provides evidence for a chain reaction initiated by VUV-induced CO splitting, which is enhanced in the presence of H and silica. When the reaction is carried out in the presence of silica or alumina surfaces, CO yields are increased and CH is formed as the only other detected product. CH production is not promoted by traditional photocatalysts such as TiO under these conditions. Assuming improvements in lamp and reactor efficiencies with scale up, or coupling with other available CO/CO hydrogenation techniques, these results reveal a potential, simple strategy by which CO could be valorized.

Quantum mechanical study of the attosecond nonlinear Fourier transform spectroscopy of carbon dioxide

“…This reaction provides a one-step route towards CO 2 reduction to carbon monoxide 30 and is in scope of studies on the negative emission technologies. [31][32][33] From a broader perspective, carbon dioxide excited with energetic (UV/VUV/XUV) photons undergoes a series of fundamental photochemical processes typical of highly energy loaded molecular systems. These include non-adiabatic interactions between Rydberg and valence electronic states, 28 roaming dissociation pathways leading to unusual photochemical products, 24,34 or dissociative VUV photoionization.…”