Title : Non-noble metal based catalysts for green and sustainable energy production
Abstract:
The statistical data explored from 2018 onwards estimated that 79.5% of the world’ s energy economy is dependent on non – renewable and conventional energy economy sources fossil fuels such as coal, oil, natural gas, etc. The rapid use and environmental impact of fossil fuels are significant worries for policymakers and the public. This concern has prompted scientists and engineers to seek green energy alternatives, which are generated using comparatively low carbon footprint renewable resources such as wind, solar, hydro-power, or geothermal energy. Hydrogen is seen as a promising and eco-friendly alternative to fossil fuels, offering a clean energy source with the potential to address environmental concerns. Hydrogen has future potential as an energy carrier due to its high energy content [120 MJ/kg on mass basis] and water as by product. Electrochemical water splitting has gained significant attention from researchers and stakeholders because of its simplicity, capability for high purity, and potential for scalable applications. Hydrogen production using water splitting process, include two half- cell reactions, hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The transition towards sustainable energy production demands efficient hydrogen generation methods, with electrolysis emerging as a promising avenue. However, prevalent challenges hinder its widespread adoption. Specifically, low yields and exorbitant costs characterize current electrolysis techniques. Furthermore, reliance on precious metals such as Pt, Pd, Ir, and Ru for the crucial Hydrogen Evolution Reaction (HER) and Oxygen Evolution Reaction (OER) poses significant hurdles due to their limited abundance and geopolitical complexities, rendering commercialization daunting. Hence The proposed research aims to explore non-noble metal such as Ni, Fe, Co, for water splitting to generate hydrogen energy through the synthesis, characterization, and optimization of Layered Double Hydroxides (LDHs) as catalysts for OER/HER electrode.
More specifically the present research focuses on Nickel–iron layered double hydroxides (NiFe-LDHs), which serve as excellent alternatives for the oxygen evolution reaction (OER) process due to their affordability and excellent properties in alkaline conditions. NiFe-LDHs were synthesized with different Ni:Fe molar ratios and systematically studied their electrocatalytic activity toward the OER in alkaline water splitting. The structural, morphological and electronic properties, of the synthesized materials were thoroughly examined respectively using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and X-ray photoelectron spectroscopy (XPS). The findings showed that an optimized Ni:Fe ratio of 2:1 considerably improves the OER performance due to the large electrochemically active surface area that results in better Ni2+/Ni3+ redox transition. The sample with Ni:Fe ratio of 2:1 has the highest charge transfer efficiency (Rct), the lowest overpotential (205 mV at 10 mA.cm-2) and Tafel slope (35 mV.dec-1). This study shows that building high-performance, non-noble metal-based OER catalysts for sustainable water electrolysis requires precise metal ratio control and an awareness of structure–activity correlations.
