Recent progress on non-noble metal catalysts for the deoxydehydration of biomass-derived oxygenates

Abstract

The utilization of renewable energy represents an effective way to address current issues associated with fossil fuels. Biomass is considered one type of renewable energy resources with abundant reserves on earth. However, the high oxygen contents and high degree of functionalization of biomass have hindered the direct exploitation of biomass for the production of fuels and chemicals. Considerable efforts have been devoted to developing effective deoxygenation methods capable of reducing the oxygen contents of biomass and its derivatives. The deoxydehydration (DODH) of biomass derivatives to generate olefins over oxophilic metal catalysts is considered a very useful approach in eliminating vicinal OH groups. In recent years, catalysts based on non-noble metals such as Mo, W, and V featuring good catalytic performance have emerged as promising alternatives to classical noble Re-based catalysts for DODH. This review aims to summarize the progress on the DODH of biomass-derived vicinal diols catalyzed by non-noble metals such as Mo, W, and V, with an emphasis on the preparation of catalysts, optimization of experimental conditions, and mechanistic studies. By surveying the performance of non-noble metal catalysts, key factors that determine the DODH activity were proposed, including the choice of reductant, the electronic and steric effects of ligand, and the interaction between solid support and metal center. The latter two could adjust the redox properties of metal centers by directly bonding with ligand or solid support.