Publications

Electrocatalytic transformation of biosourced organic molecules

(https://doi.org/10.1016/j.coelec.2023.101210)

Electrolysis of lignin for production of chemicals and hydrogen

(https://doi.org/10.1016/j.coelec.2023.101255)

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Design of Experiments for Optimized Synthesis of Carbon-Supported Ni Nanoparticles: A Green Chemistry Approach

(https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/celc.202400189)

Abstract

Metallic nickel nanoparticles supported on a high specific surface area carbon powder were synthesized by a classical polyol method without external reducing agent or surfactant. Ni/C materials were characterized by TGA, XRD, cyclic and linear voltammetry. To decrease the number of experiments, a Taguchi design of experiments (DoE) was implemented and the effects of different synthesis parameters (nature of the nickel salt, loading of Ni on carbon, nNaOH/nNi ratio and reaction time at reflux) on different responses (crystallite size, electrochemically active surface area and current density for the glucose oxidation reaction at 1.5 V) determined. Optimization of parameter values for decreasing the crystallite size down to 14 nm was achieved using the DoE. For the other responses, strong interactions between parameters avoided straightforward optimization of parameter values. However, some trends could be drawn from the experimental matrix showing that the synthesis of a catalyst loaded with only 10 wt% Ni, with NiCl2 as precursor salt, with a nNaOH/nNi ratio of 6 for 80 minutes at reflux was a good compromise between atom, time and energy savings, costs efficiencies, and electrochemically active surface area and catalytic activity towards the glucose oxidation reaction, particularly in terms of mass activity.

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Can we completely suppress the oxygen evolution reaction in a glucose electrolyser? Three experimental evidences

International Journal of Hydrogen Energy 73 (2024) 112–117

Abstract


Electroreduction of small molecules in aqueous solution often competes with the hydrogen evolution reaction (HER), especially if the reaction is driven even moderately hard using a large overpotential. Here, the oxygen reduction reaction (ORR) was studied under proton diffusion-limited conditions in slightly acidic electrolytes – a model system to study the relative transport kinetics of protons and reactants to an electrocatalyst and the relationship between transport and catalytic performance. Using dealloyed nanoporous nickel-platinum (np-NiPt) electrodes, we find the hydrogen evolution reaction can be completely suppressed even at high overpotentials (-400 mV vs. RHE). In addition, the mechanism of oxygen reduction can be changed by using buffered versus unbuffered solutions, suggesting the reaction selectivity is associated with a transient rise (or lack thereof) in the interface pH at the np-NiPt surface. Independently controlling reactant transport to electrocatalyst surfaces at high overpotentials exhibited a surprisingly rich phenomenology that may offer a generalizable strategy to increase activity and selectivity during electroreduction reactions.