Unveiling the Multifunction of SCoFeCS: Remarkably Boosting Electrocatalytic Activity in Renewable Energy-Powered Overall Alkaline Water Splitting

We developed core–shell structured (CS) CoFe hydroxides coated by a defective RGO shell via solvothermal (SCoFeCS) and hydrothermal (HCoFe@RGO) methods. SCoFeCS provided more active sites with a transmissive corridor and high conductivity, with a large surface area, to ameliorate the catalytic efficiency. The optimal SCoFeCS displays exceptional trifunctional properties for H2 and O2 evolution, UOR, and MSWO at low potentials (OER: 299 mV; 112 mV dec–1, UOR: 1.40 V; 72 mVdec–1, and MSWO: 1.50 V; 82 mVdec–1). SCoFeCS shows higher catalytic efficiency than HCoFe@RGO (359 mV; 299 mV dec–1) due to strong synergistic coupling between CoFe and the rGO matrix. The calculated areas under MOOH formation peaks for SCoFeCS, HCoFe@RGO, and SCo@RGO are 2.603 × 10–5 AV, 1.139 × 10–5 AV, and 1.079 × 10–5 AV and active sites are 3.249 × 1016, 1.422 × 1016, and 1.347 × 1016, respectively. The superaerophobicity of SCoFeCS is validated by the fast gas bubble evolution from the SCoFeCS surface. The ultrastability of SCoFeCS for industrial application was confirmed by durability at 10/100 mA cm–2 for OER (GC: 24 h, 2.4%/-; NF: 100 h, 3.2/5.1%), UOR (100 h/2.8%), MMSWO (100 h/3.4%), and overall water splitting (100 h, 2.7%/4.1%). The effect of pH and the addition of tetramethylammonium cation (TMA+) reveal that SCoFeCS follows the lattice oxygen mechanism (LOM). The multiapplications of SCoFeCS proposed to be an auspicious catalyst for fuel cell applications.