Sn/Ta Bimetallic Oxides as Efficient Solid Acid Catalysts for the Catalytic Conversion of Dihydroxyacetone to Lactic Acid

ABSTRACT The depletion of fossil fuels has intensified research into renewable biomass, with lactic acid (LA) as a key platform chemical. In this work, Sn/Ta bimetallic oxide solid acid catalysts were synthesized via a P123‐assisted coprecipitation method. XRD analysis confirmed crystalline SnO 2 , while Ta 2 O 5 remained highly dispersed and amorphous. The P123 template significantly enhanced the specific surface area and modulated the surface acidity, increasing the proportion of Lewis acid sites, as evidenced by pyridine‐FTIR. The optimal Sn/Ta‐P123 (1:1) catalyst achieved a lactic acid yield of 99.4% from dihydroxyacetone (DHA) under mild conditions (160°C). In situ DRIFTS reveals that DHA adopts a bidentate adsorption configuration on Lewis acid sites (Sn 4+ /Ta 5+ ), followed by a Brønsted‐assisted dehydration‐rearrangement cascade, in which the Lewis‐acid‐catalyzed isomerization of pyruvaldehyde to lactic acid is the rate‐determining step. The catalyst exhibited good stability over six reuse cycles. This work presents an effective strategy for designing efficient solid acid catalysts for biomass conversion.