Lewis acid (Ni2+, Co2+/3+or Zn2+) modified electron-deficient Ir4+in IrO2/CuO for promoting methane oxidation to ethanol and methanol
This work delineates the first attempt to tune the product distribution between methanol and ethanol in the direct oxidation of methane reaction by incorporating Lewis acids Ni2+, Co2+/3+or Zn2+into IrO2/CuO. The electrophilicity of Ir4+and the (LAS-BAS)/LAS ratio (LAS: Lewis acid sites, BAS: Brønsted acid sites) are demonstrated to be two reactivity descriptors motivating CH4activation and ethanol formation, respectively. Electron-deficient Ir4+motivates enriched *CH3concentration and subsequent C-C coupling for C2H4formation, while the Lewis acid promotes ethanol formation from C2H4involving lattice O and H2O. The ethanol selectivity presents a quasi-linear relationship with (LAS-BAS)/LAS.