Single-source-precursor synthesis of porous Ni2Si/SiOC composites as oxygen evolution reaction electrocatalysts†

Abstract

In this study, a novel carbon-rich Ni₂Si/SiOC ceramic composite was successfully synthesized via a polymer-derived ceramic approach, which was found to be catalytically active for the oxygen evolution reaction (OER). The synthesis involved the reaction of a commercially available carbon-rich polysiloxane precursor SPR-684 and nickel acetylacetonate, forming a Ni-containing single-source-precursor (SSP). Furthermore, to investigate the influence of porosity on OER performance, polystyrene (PS) was used as a sacrificial template for pore formation. Thermal treatment of the obtained mixture of SSP and PS at 1400 °C led to the encapsulation of Ni₂Si particles by structurally ordered carbon, potentially enhancing the electrical conductivity of the composite. Additionally, the sample prepared at 1400 °C presented weight fractions of the crystalline phases of Ni₂Si and SiC in the amounts of 39.6 wt% and 29.3 wt%, respectively. Owing to the support of increased conductive carbon formation, the sample obtained at 1400 °C demonstrated the best overpotential of 336 mV versus the reversible hydrogen electrode (RHE) at a current density of 10 mA cm⁻² in 1 M KOH, indicating its enhanced performance for the OER.