Toward Selective Dehydrogenation of Glycerol to LacticAcid over Bimetallic Pt–Co/CeO x Catalysts

Selective synthesis of lactic acid from bio-derived substrates still remains a grand challenge. We reported a series of unique bimetallic Pt-Co/CeOx catalysts, prepared by fractional precipitation method. Strong electronic coupling for Pt-Co is found to enhance activity towards dehydrogenation (C-H bond cleavage) of glycerol, as evidenced from XPS and TEM studies of the catalysts. Detectable electro affinity of PtCo trends to gain electron from CeOx support, thus some side reactions (such as C-C and C-O bond cleavage) are largely restrained. Such hybridized structures lead to remarkable activity (TOF: 1533.9 h-1) with good selectivity towards lactic acid (87.7%) and total organic acids (> 95%) at 200 oC. In addition, the effect of reaction temperature and substrate concentration on initial reaction rate reveals that dehydrogenation of glycerol possibly follows dual-site mechanism, where both glycerol and base need to be activated on bimetallic Pt-Co surface. Furthermore, the plausible reaction pathway is ...