(614a) Selective Oxidation of 1,2-Propanediol to Pyruvate Or Lactate in Alkaline Media Over Supported Au and Pt Nanoparticles in Anion Exchange Membrane Fuel Cell (AEMFC) and Electrocatalytic Flow Reactors

Renewable biomass has received great interest for its potential to replace petroleum as the primary feedstock for liquid fuels, chemicals, and polymeric materials. Biorenewable 1,2-propanediol (PDO) may be produced from the catalytic hydrogenolysis of glycerol, a major co-product of biodiesel production. PDO is a 3-carbon (C3) diol featuring vicinal primary and secondary alcohol groups which may be selectively oxidized to form lactate, which has potential as a feedstock in biodegradable polymer production, or pyruvate which is an important building-block in chemical, pharmaceutical, and agrochemical industries. In this talk, I will present the selective oxidation of PDO to pyruvate or lactate in an anion exchange membrane fuel cell (AEMFC) and a custom-made AEM-based electrocatalytic flow reactor, both using carbon supported Pt and Au nanoparticles (Pt/C or Au/C) on carbon cloth as the anode catalyst layer. The main oxidation product on Pt/C was lactate (85-90%), while Au/C displayed potential-controlled selectivity to pyruvate (20-55%) with lactate as the other main product. At sufficient anode potential, lactate was further oxidized to pyruvate on Au/C while C-C bond breaking was preferred on Pt/C. Based on the observed oxidation products and additional three-electrode voltammetry study of product intermediates, a reaction pathway was proposed to map the unique catalytic properties of Au/C and Pt/C. Density-functional theory (DFT) simulations were performed to calculate reaction energies, and the theoretically favorable pathway agreed with the experimentally proposed pathway. This work unveils new insight to the role of supported nanoparticle electrocatalysts for production of important chemicals from biorenewable sources.