Oxidative dehydrogenation of ethanol over AgLi–Al2O3 catalysts containing different phases of alumina

•The mixed γ- and χ-alumina exhibits higher activity than each phase alone.•Activity depends on weak basic site, Agnδ + clusters and reduction of catalysts.•Lower activity will be observed if the reduction of Agnδ + to Ag0 occurs.•With these AgLi–Al2O3 catalysts, the selectivity to acetaldehyde can be 100%.

Oxidative dehydrogenation of ethanol over the AgLi–Al2O3 catalysts having different phase compositions of alumina was investigated. The pure gamma (CHI00), pure chi (CHI100) and equally mixed phases (CHI50) derived from the solvothermal synthesis can play important roles on the physicochemical properties of AgLi–Al2O3 catalysts. Especially, the amount of weak basic sites, the oxidation state of Ag, and the reduction behaviors of catalysts are crucial in determining the ethanol conversion and product selectivity. It was found that increased amounts of weak basic sites and Agnδ + clusters enhanced the catalytic activity as seen for the AgLi–CHI50 catalyst.

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