Recently, Professor Lingzhi Wang and Professor Jinlong Zhang's research team at the School of Chemistry and Molecular Engineering, East China University of Science and Technology, have made significant advancements in the selective conversion of methane to ethanol using a photocatalytic system based on a three-phase interface floating membrane strategy, achieving excellent activity under ambient conditions. Their relevant research has been published in the "Journal of the American Chemical Society".
Utilizing photocatalytic technology to selectively oxidize methane into oxygen-containing compounds is an attractive yet challenging task. While some strategies have successfully achieved high conversion rates and suppressed overoxidation, the high-pressure environment still poses significant limitations on selective control.
Building upon previous studies, the research team constructed a mesoporous alginate hydrogel membrane embedded with Fe(III) for stabilizing floating C3N4, termed Fe(III)@ACN. The lightweight and large-pore structure of this gel enables it to stably float at the gas-water interface, forming a gas-solid-liquid three-phase interface, which facilitates the contact between methane molecules and active species within the pores by shortening the gas diffusion path under atmospheric pressure. Under illumination, the hydrophilicity of Fe(III)@ACN triggers the water oxidation reaction (WOR) on C3N4 to produce H2O2. Simultaneously, photoexcited electrons reduce Fe(III) to Fe(II), initiating the Fenton reaction with H2O2 to generate ·OH. The enhanced gas mass transfer at the three-phase interface promotes the reaction of CH4 with ·OH to produce ·CH3, ultimately facilitating C–C coupling under conditions where the concentrations of ·CH3 and ·OH are matched, thus enabling the conversion from CH4 to CH3OH and then to C2H5OH.
