Solid-state synthesis of CdFe₂O₄ binary catalyst for potential application in renewable hydrogen fuel generation

Clean energy is highly needed at this time when the energy requirements are rapidly increasing. The observed increasing energy requirement are largely due to continued industrialization and global population explosion. The current means of energy source is not sustainable because of several reasons, most importantly, environmental pollution and human health deterioration due to burning of fossil fuels. Therefore, this study develops a new catalyst for hydrogen and oxygen evolution by water splitting as a potential energy vector. The binary metal oxide catalyst CdFe₂O₄ was synthesized by the solventless solid-mechanical alloying method. The as-prepared catalyst was well characterized by several methods including field emission scanning electron microscopy (FESEM), X-ray diffraction spectroscopy (XRD), X-ray photoelectron spectroscopy (XPS), Fourier Transform infrared red spectroscopy (FTIR), energy dispersive X-ray spectroscopy (XEDS). The as-prepared catalyst, CdFe₂O₄ was successfully applied for water electrolysis at a moderate overpotential (470 mV). Specifically, the onset potential for the oxygen and hydrogen evolution reactions (OER and HER) were 1.6 V_/RHE and 0.2 V_/RHE respectively (vs. the reversible hydrogen electrode). The electrode potential required to reach 10 mA/cm^-2 for OER (in alkaline medium) and HER (in acidic medium) was 1.70 V_/RHE (corresponding to overpotential η = 0.47 and - 0.30 V_/RHE (η = - 0.30 V) respectively. Similarly, the developed OER and HER catalyst displayed high current and potential stability for a period of 12 h. This approach is seen as the right track of making water electrolysis for hydrogen energy feasible through provision of low-energy requirement for the electrolytic process. Therefore, CdFe₂O₄ is a potential water splitting catalyst for hydrogen evolution which is a clean fuel and an antidote for world dependence on fossil fuel for energy generation.