Photoelectrocatalytic Valorization of Biomass-Derived Succinic Acid into Ethylene Coupled with Hydrogen Production over an Ultrathin BiO<sub><i>x</i></sub>-Covered TiO<sub>2</sub>
Qiujin Shi, Jing Li, Yuanbo Liu, Kejian Kong, An-Zhen Li, Haohong Duan
Abstract
Photoelectrochemical (PEC) cells have been extensively studied in water splitting to produce H 2, but the sluggish kinetics of the oxygen evolution reaction (OER) remains a huge challenge. Here, we reported a PEC strategy for biomass-derived succinic acid decarboxylation to replace OER, with the production of ethylene (C 2 H 4 ) as a high-demand chemical. By synthesizing a bismuth oxide supported on titanium oxide (BiO x /TiO 2 ) as the photoanode, C 2 H 4 was efficiently produced with 85.7 μmol/h production rate and 40% Faradaic efficiency. Simultaneously, H 2 productivity was improved by 6.5-fold compared with total water splitting (from 50.8 to 331.7 μmol/h). Structure characterizations show that BiO x forms an ultrathin layer (approximately 1.5 nm in thickness) on the TiO 2 surface with a strong interfacial interaction, inducing the formation of a type-II heterojunction with efficient charge separation and transfer. Experimental data suggest that succinic acid molecules are adsorbed over the BiO x surface with its dual carboxyl groups in a deprotonated form, facilitating the decarboxylation of succinic acid to ethylene via a non-Kolbe route. This work demonstrates the great opportunity of PEC technology for transforming renewable biomass resources into value-added chemicals with promoted H 2 fuel production under mild conditions.