Recent advances in the selective oxidation of glycerol to value-added chemicals via photocatalysis/photoelectrocatalysis

Abstract

Glycerol, as the major by-product of biodiesel, is a highly versatile molecule with three similar hydroxyl groups. Recently, great efforts have been made to find active catalysts and suitable catalytical technology to convert it into various valuable fine chemicals. Catalytic oxidation of glycerol via renewable sources of solar energy have attracted much attention because of the unique reaction pathway induced by photogenerated reactive species as well as the mild reaction conditions required. In this review, we describe the recent development of selective oxidation pathways for conversion of glycerol to value-added chemicals via photocatalysis and photoelectrocatalysis, specifically, how to realize C–OH bond oxidation to CO with other functional groups preserved, and C–C bond cleavage and oxidation to carboxyl, –COOH. Particular emphasis is paid to the design of catalyst active structures in the given reaction pathways, including semiconductors with specific adsorption sites, surface plasmon resonance metals, transition metal complex cocatalysts, and synergy with photongenerated reactive oxygen species (ROS). Therefore, this review provides an in-depth understanding of the mechanisms for selective oxidation of glycerol via photocatalysis/photoelectrocatalysis as important guidance for the design of efficient catalysts.