Surface/Lattice Oxygen Synergism of Durable CuO Catalysts for Tandem Dehydrogenation–Oxidation of Glycerol to Carboxylic Acids in Oxygen-Free Medium

Abstract

Catalytic dehydrogenation–oxidation of bio-oxygenates to carboxylic acids and green H2 has been considered a key technology for biorefineries. Composition, size, and morphology are critical parameters for solid catalysts. However, the synergism of surface/lattice oxygen in inexpensive metal oxide catalysts is largely unexplored in this area. In this work, a systematic study on the surface/lattice oxygen synergism of crystallized CuO catalysts has been performed using glycerol dehydrogenation as an example. The key finding is that surface oxygen contributes to enhanced C–H bond activation, while lattice oxygen is key for tandem dehydrogenation–oxidation reactions. Thus, the crystallized CuO catalysts display a 2-fold enhancement in activity and 7-fold improvement in the durability of CuO catalysts, leading to almost 93% reduction of Cu leaching with negligible deactivation. The methodology discussed in this work will provide insights into the rational design of cost-effective CuO materials for other important aqueous dehydrogenation reactions in the chemical industry.