Highly Selective Electrocatalytic Hydrogenation of Biomass-Derived Aldehydes to Alcohols over a One-Dimensional Sulfur-Doped TiO ₂ Nanocatalyst

Electrocatalytic hydrogenation (ECH) of biomass-derived aldehydes to alcohols under ambient conditions using H2O as a hydrogen source represents a green and sustainable strategy to replace conventional thermal methods that rely on fossil resources. However, achieving high selectivity for alcohol products at high conversion is still a significant challenge, owing to competition from the hydrogen evolution reaction and over-reduction. Herein, we report a 1D sulfur-doped TiO2 catalyst loading on the Ti microfiltration membrane (S-TiO2/Ti) for efficient ECH of biomass-derived aldehydes to alcohols via a proton-coupled electron transfer mechanism in an electrocatalytic membrane reactor (ECMR). As a typical demonstration, during ECH of vanillin (VAN) to vanillyl alcohol (VAL), it exhibits a VAN conversion of 90.2% with a high VAL selectivity of >99%, and the corresponding Faradaic efficiency (FE) is 89.2% in neutral media. Experimental studies reveal that the excellent catalytic activity can be attributed to the introduction of S, which enhances the electrical conductivity of the catalyst and promotes the desorption behavior of VAL. The S-TiO2/Ti membrane electrode demonstrates effectiveness for furfural and aromatic aldehydes to the corresponding alcohols. This work demonstrates an efficient catalyst for electrochemical biomass upgrading with high productivity that shows potential for practical applications.