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

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.