Photoelectrochemical valorization of cellulose over bismuth-based oxide modified titanium dioxide photoanodes

Valorizing biomass waste through photoelectrochemical (PEC) methodology provides an attractive strategy for generating H₂ and value-added chemicals by enabling a carbon–neutral cycle. Herein, we present an investigation of a series of bismuth-based oxide-modified TiO₂ as the photoanode for PEC valorization of cellulose in aqueous solution. The bismuth-based oxide was synthesized onto a TiO₂ photoanode by a chemical bath deposition (CBD) method followed by heat treatments. The composition of the materials was adjusted by varying the concentration of the Cu²⁺ and Bi³⁺ precursors. The research shows that Bi₂O₃ effectively suppresses the water oxidation reaction over TiO₂, a competitive side reaction in PEC cellulose oxidation, resulting in a Faradaic efficiency (FE) of 83.9 ± 4.9 % toward formate production. In contrast, unmodified TiO₂ photoanode only exhibits a FE of 25.3 ± 3.7 %. On the other hand, the photoelectrode showed insufficient oxidative force for both water and cellulose oxidation by the surface modification of CuBi₂O₄.