Advances and Challenges of Photocatalytic Methane C—C Coupling
Xueyuan Wang, Nengchao Luo, Feng Wang
Abstract
Comprehensive Summary Methane, the main component of natural gas and shale gas, can be converted to upgraded fuels, syngas and value‐added chemicals. Due to the nonpolar character of methane and large bond dissociation energy of sp 3 C—H bond, methane conversion requires strong oxidants or acids/bases for its activation. Photocatalysis capable of inducing highly oxidative surrogates enables methane C—H bond scission at room temperature, thereby avoiding side reactions and coke formation caused by high reaction temperature. The scission of methane C—H bond generates •CH 3 that may undergo C—C bond coupling with carbon radicals, which is a versatile way to obtain C 2+ chemicals. Apart from the kinetically slow activation of methane C—H bond, photocatalysis also suffers from complex product distributions owing to the presence of varieties of radicals during photocatalytic methane conversion, and a low selectivity of desired C 2+ products was achieved. In this review, we summarize the recent advances of photocatalytic methane conversion with emphasis on methane C—C bond coupling. Methods of methane C—H bond activation and radical manipulation for selective C—C bond coupling were discussed in detail. We hope this review may be a valuable guide of future work in photocatalytic methane C—C coupling.