Oxidative dehydrogenation of lactic acid to pyruvic acid over Pb-Pt bimetallic supported on carbon materials

Abstract

Various carbon materials, including activated carbon, flake graphite, carbon black and multiwall carbon nanotubes, were adopted as supports for lead-promoted platinum catalysts in the investigation of aqueous-phase oxidative dehydrogenation of lactic acid to produce pyruvic acid. Among them, the nanoscale 3Pb-1Pt/carbon black catalyst showed the highest TOF (769h−1) and yielded 60% pyruvic acid within 20min under mild conditions. N2 adsorption, Raman spectroscopy, thermogravimetry, SEM, TEM and XPS were performed to investigate their different structures, graphitization degrees, metal particle sizes and surface oxidation states. Under the current conditions, smaller support particle size is essential for the enhanced lactic acid transformation rate by favoring the diffusion of reactants; less graphitic structure of catalyst is also beneficial by improving metal particle dispersion and facilitating the exposure of metals.