(365c) Utility of Dual-Layer Photoanode for Photoelectrochemical Biomass Conversion

Photoelectrochemical (PEC) cells use solar energy to power desirable chemical reactions, such as splitting water into hydrogen, a fuel source, and oxygen. It has been shown that certain catalysts improve the efficiency of PEC water splitting, but less work has been done developing catalysts for chemical production in PECs. Here, we present the synthesis and characterization of electrocatalysts which enhance the efficiency of other oxidation reactions, where water oxidation is actually the competing reaction. Specifically, we have demonstrated improved performance of dual layer photoanodes on the oxidation of 5-hydroxymethylfurfural (HMF), a biomass derivative. Under 1.5 AM G illumination, we observe 21% conversion of HMF on a single layer photoanode while the addition of an electrodeposited catalyst increases HMF conversion to 33%. Both linear sweep voltammetry and chronoamperometry measurements indicate the catalyst positively affects the biomass oxidation reaction but not water oxidation. By adjusting reaction conditions and controlling the interfaces between the photoanode layers as well as the electrolyte, electrocatalysts may be fine-tuned to behave differently. This result opens new doors to the utility of PECs for applications beyond water splitting.