We demonstrate a catalytic process for xylitol production based on the volatility and unique reactivity of diformylxylose (DFX), which can be produced at near theoretical yield from biomass and, contrary to xylose, can be easily purified by distillation. The apparent rate-limiting step was independent of hydrogen pressure, and catalytic studies showed a slow evolution of the Pt/C catalyst that led to tripling of the xylitol yield. In-depth catalyst characterization attributed this activity increase to the formation of acidic carbon deposits, which created acid sites in close proximity to Pt. These proximal sites accelerated DFX hydrolysis while avoiding unfavorable isomerization reactions.