Pt₂₀Ru_xSn_y nanoparticles dispersed on mesoporous carbon CMK-3 and their application in the oxidation of 2-carbon alcohols and fermentation effluent

We report the synthesis of Pt-Sn binary and Pt-Ru-Sn ternary alloy nanoparticles (NPs) dispersed on mesoporous carbon CMK-3 for bioalcohol fuel cell applications where ethanol, ethylene glycol, and fermentative hydrogen production effluent were used as the fuels. The proposed alloy electrocatalysts, denoted as Pt₂₀Ru_xSn_y@C (where 20, x, and y represent the weight fractions of Pt, Ru, and Sn, respectively), were examined using scanning electron microscopy, energy-dispersive X-ray spectroscopy mapping, transmission electron microscopy, Brunauer-Emmett-Teller measurements, X-ray diffraction analysis, and electrochemical measurements, in order to determine their morphologies, microstructures, compositions, phase structures, and electrochemical characteristics. The effects of the Sn content on the following factors were examined: 1) average particle size of the alloy NPs, 2) mesoporosity, 3) electrochemically active surfaces of Pt₂₀Ru_xSn_y@C, and 4) ethanol oxidation reaction and ethylene glycol oxidation reaction activities. Higher Sn contents improved the catalytic efficiency of Pt₂₀Ru_xSn_y when x = 0 or x = 10, with the optimized compositions being Pt₂₀Sn₃₀ and Pt₂₀Ru₁₀Sn₁₅ for the binary and ternary alloys, respectively. Based on the ethanol and ethylene glycol oxidation reactions, we explain the role of Sn in promoting C[sbnd]C bond cleavage and in improving catalyst tolerance against poisoning. Overall, for both the ethanol system and the ethylene glycol system, the catalytic activities could be arranged as follows: Pt₂₀Ru₁₀Sn₁₅@C > Pt₂₀Sn₃₀@C > Pt₂₀Ru₁₀@C > Pt₂₀@C. The chronoamperometric measurement shows that Pt₂₀Ru₁₀Sn₁₅@C is more stable than commercial E-TEK Pt/C catalyst under ethanol environment. Finally, the catalyst Pt₂₀Ru₁₀Sn₁₅ was used successfully to demonstrate the feasibility of using the bioalcohol from a fermentation effluent as a fuel.