Enhanced catalytic performance and changed reaction chemistry for electrochemical glycerol oxidation by atomic-layer-deposited Pt-nanoparticle catalysts

Abstract

Atomically controlled thin TiO2 layers were coated onto a carbon-supported Pt nanoparticle (Pt/C) surface using an atomic layer deposition (ALD) technique. Then, the resulting TiO2 coated Pt/C (ALD(TiO2)-Pt/C) was heat-treated at 150 degrees C under N-2 atmosphere. The heat-treated ALD(TiO2)-Pt/C (ALD(TiO2)-Pt/C(150 H T)) catalyst demonstrated improved electrocatalytic glycerol oxidation reaction (GOR) activity with a turnover frequency (TOF) 3-times higher than for uncoated Pt/C catalyst. Interestingly, the ALD(TiO2)-Pt/C(150 H T) catalyst maintained its catalytic GOR performance after a cyclic voltammetry (CV) stability test of 1200 cycles, preventing Pt sintering due to strong Pt-TiO2 interaction. The reaction chemistry for GOR on the ALD(TiO2)-Pt/C(150 H T) catalyst also changed due to the newly created Pt-TiO2 interfaces, producing more oxidized chemicals such as glyceric acid and glycolic acid. The enhanced GOR performance is related to the formation of new Pt-O-Ti bonds and to change in the physicochemical properties of the Pt by interaction between the Pt nanoparticles and ALD-coated TiO2.