Investigation of Fe -ZIF-۸@SiO₂ Nanocomposite as a Bifunctional Electrocatalyst for Oxygen/Hydrogen Evolution Reactions

In the modern era, escalating energy demands and accelerating environmental degradation have emerged as critical global challenges, necessitating urgent and sustainable solutions. Excessive reliance on finite fossil fuels has intensified carbon emissions and exacerbated ecological stress. Consequently, renewable and sustainable energy sources —including solar, wind, geothermal, and hydroelectric power —have attracted significant attention due to their minimal environmental footprint. Electrochemical processes such as the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR) are pivotal to advancing clean energy technologies. The OER process is particularly sensitive to catalyst performance, which governs product yield, energy efficiency, and system durability. Although noble-metal-based catalysts like IrO₂ and RuO₂ exhibit high activity, their prohibitive costs and resource scarcity restrict large-scale implementation. In this study, we report the synthesis of Fe-ZIF-۸@SiO₂ nanohybrid via a hard-templating and pyrolysis approach, utilizing iron-doped ZIF-۸ as a precursor. Comprehensive characterization using X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) coupling with elemental mapping, and Fourier-transform infrared spectroscopy (FT-IR) confirms the successful formation of a hierarchical porous architecture and synergistic dual active sites. The electrocatalyst sample was tested on a glassy carbon electrode (GCE) without the use of any binder. Electrochemical evaluations reveal that the Fe-ZIF-۸@SiO₂ exhibits outstanding activity with overpotentials of ۳۷۰ mV and ۳۲۰ mV at a current density of ۲.۵ mA cm-۲ and Tafel slopes of ۱۱۴ mV dec-۱ and ۷۵ mV dec-۱ in both alkaline and acidic media for OER and HER, respectively. These findings highlight the considerable promise of this nanohybrid material for next-generation clean energy applications.

کلیدواژه ها:

Fe-ZIF-۸@SiO₂ ، HER ، OER ، Bifunctional