Electrocatalytic properties of nanomaterials synthesized from “Bromide Anion Exchange” method - Investigations of glucose and glycerol oxidation

Tailor-designed nanoparticle-based PdNiSn catalyst as a potential anode for glycerol fuel cells

In order to effectively use glycerol as a fuel in direct glycerol fuel cells, a catalyst that can break the C-C bond and enhance the electro-oxidation of glycerol to CO2 is necessary. In this particular investigation, a palladium-nickel-tin nanocomposite electrodeposited on a glassy carbon electrode (PdNiSn/GC) exhibited excellent activity towards the electro-oxidation of glycerol, thanks to the synergistic effect of the catalyst composition. The PdNiSn/GC surface generated a peak current (Ip) that was 2.5 times higher than that obtained at a Pd/GC electrode, with a cathodic shift in the onset potential (Eonset) of approximately 300 mV. Additionally, the current obtained at the PdNiSn/GC surface remained stable during continuous electrolysis. Capacitance measurements were used to interpret the results of the electrocatalytic activity, and high-performance liquid chromatography indicated that the products of the glycerol electro-oxidation reaction were oxalic acid and formic acid, which were subsequently oxidized to CO2, as revealed by the charge calculations. The results depict that the synergy between Pd, β-Ni(OH)2, and SnO2 is crucial for boosting GEOR through enhancing the C-C bond cleavage and completely oxidize the reaction intermediates to CO2.

Enhanced Performance of Sn@Pt Core-Shell Nanocatalysts Supported on Two Different Carbon Structures for the Hydrogen Oxidation Reaction in Acid Media

Sn@Pt core-shell nanocatalysts, supported on Vulcan XC-72 and home-developed nitrogen-doped graphene (Sn@Pt/C and Sn@Pt/NG, respectively), were evaluated for the hydrogen oxidation reaction (HOR) in acid electrolyte. The nanocatalysts were synthesized by the bromide anion exchange (BAE) method. TEM characterization confirmed the nanosize nature of Sn@Pt/C and Sn@Pt/NG, with an average particle size of 2.1 and 2.3 nm, respectively. Sn@Pt/C delivered a similar mass limiting current density (jl, m) of the HOR compared to Sn@Pt/NG, which was higher than those of Pt/C and Pt/NG (ca. 2 and 2.3-fold increase, respectively). Moreover, the Sn@Pt/C and Sn@Pt/NG core-shell nanocatalysts demonstrated a higher specific activity related to Pt/C and Pt/NG. Mass and specific Tafel slopes further demonstrated the improved catalytic activity of Sn@Pt/C for the HOR, followed by Sn@Pt/NG. The application of the nanocatalysts was proposed for polymer electrolyte membrane fuel cells (PEMFC).

Rhodium effects on Pt anode materials in a direct alkaline ethanol fuel cell

The development of efficient catalysts for ethanol oxidation in alkaline medium requires a synthetic approach that may prevent the surfactant molecules from being adsorbed at the catalytic sites and decreasing the electrochemical performance of the final direct ethanol fuel cell. Toward this goal, the recently reported surfactant-less Bromide Anion Exchange (BAE) method, appears as a promising route to conveniently aim at preparing PtRh alloys dispersed on carbon substrates. The catalysts prepared herein by the BAE method were characterized physicochemically to obtain structural information on the PtRh/C nanomaterials, their morphology (size and shape), and their chemical and surface composition. Electrochemical behavior and properties of these electrodes were then investigated in a half-cell before the implementation of a direct ethanol fuel cell (DEFC) in a home-made anion exchange membrane Teflon cell. The analysis of the electrolytic solution in the anodic compartment by chromatography revealed that acetate was the major reaction product and the carbonate amount increased with the Rh content in the bimetallic composition. With 2.8–3.6 nm particle sizes, the Pt₅₀Rh₅₀/C catalyst exhibited the highest activity towards the ethanol electrooxidation.

The development of efficient catalysts for ethanol oxidation in alkaline medium requires an approach that avoids surfactant molecules from being adsorbed at active sites and decreasing the electrochemical performance of the direct ethanol fuel cell.

Recent advances in the electrooxidation of biomass-based organic molecules for energy, chemicals and hydrogen production

The recent developments in biomass-derivative fuelled electrochemical converters for electricity or hydrogen production together with chemical electrosynthesis have been reviewed.

Electrocatalytic valorisation of biomass derived chemicals

Recent progress in electro-valorization of biomass-derived intermediates is reviewed, while a perspective on future R&D in this field is provided.

High impact of the reducing agent on palladium nanomaterials: new insights from X-ray photoelectron spectroscopy and oxygen reduction reaction

The nature of the reduction agent changes drastically the palladium nanomaterials chemical stability, which subsequently alters earnestly their catalytic performances.