Enabling Direct Photoelectrochemical H₂ Production using Alternative Oxidation Reactions on WO₃.

Abstract

The efficient and inexpensive conversion of solar energy into chemical bonds, such as in H2 via thephotoelectrochemical splitting of H2O, is a promising route to produce green industrial feedstocks and renewablefuels, which is a key goal of the NCCR Catalysis. However, the oxidation product of the water splitting reaction,O2, has little economic or industrial value. Thus, upgrading key chemical species using alternative oxidationreactions is an emerging trend. WO3 has been identified as a unique photoanode material for this purpose sinceit performs poorly in the oxygen evolution reaction in H2O. Herein we highlight a collaboration in the NCCRCatalysis that has gained insights at the atomic level of the WO3 surface with ab initio computational methodsthat help to explain its unique catalytic activity. These computational efforts give new context to experimentalresults employing WO3 photoanodes for the direct photoelectrochemical oxidation of biomass-derived 5-(hydroxymethyl)furfural. While yield for the desired product, 2,5-furandicarboxylic acid is low, insights into the reactionrate constants using kinetic modelling and an electrochemical technique called derivative voltammetry, giveindications on how to improve the system.