Converting glycerol aqueous solution to hydrogen energy and dihydroxyacetone by the BiVO4 photoelectrochemical cell

Replacement of oxygen evolution reaction (OER) by the more readily oxidized biomass derivatives is considered to be a promising strategy for photoelectrocatalytic water splitting hydrogen production. In this work, a biodiesel industrial waste by-product, glycerol, played the critical role for the efficient hydrogen production as well as the highly valuable dihydroxyacetone (DHA) and industrial useful formic acid production. As the glycerol was introduced, a remarkable cathodic shift of the onset potential was observed (similar to 300 mV) while the current density was 4 times higher compared to the water oxidation. The incident photon-to-current efficiency (IPCE) of BiVO4 photoanode for glycerol oxidation reached about 55%, which was 3 times higher than the system without glycerol. More importantly, during the photoelectrochemical water splitting in glycerol aqueous solution, in addition to the evolved hydrogen gas, glycerol was oxidized to valuable products with 15% dihydroxyacetone (DHA) and 85% formic acid. This strategy not only boosts the hydrogen production efficiency, keeps the photoanode very stable but also makes the biodiesel production more profitable and sustainable. (C) 2019 Elsevier Ltd. All rights reserved.