Selective light-driven methane oxidation to ethanol
摘要
Methane (CH4) photocatalytic upgrading to value-added chemicals, especially C2 products, is significant yet challenging due to sluggish energy/mass transfer and insufficient chemical driven-force in single photochemical process. Herein, we realize solar-driven CH4 oxidation to ethanol (C2H5OH) on crystalline carbon nitride (CCN) modified with Cu9S5 and Cu single atoms (Cu9S5/Cu-CCN). The integration of photothermal effect and photocatalysis overcomes CH4-to-C2H5OH conversion bottlenecks, with Cu9S5 as a hotspot to convert solar-energy to heat. In-situ characterizations demonstrate that Cu single atoms play as electron acceptor for O2 reduction to ·OOH/ · OH, while Cu9S5 acts as hole acceptor and site for CH4 adsorption, C − H activation, and C − C coupling. Theoretical calculations demonstrate that Cu9S5/Cu-CCN reduces C − C coupling energy barrier by stabilizing ·CH3 and ·CH2O. Impressively, C2H5OH productivity reaches 549.7 μmol g–1 h–1, with selectivity of 94.8% and apparent quantum efficiency of 0.9% (420 nm). This work provides a sustainable avenue for CH4 conversion to value-added chemcials.