Electrospun CSNi<sub>3</sub>C/Fe<sub>3</sub>C@C/NFs-600 Embedded in Porous Carbon shell as an Efficient Electrocatalyst for Water Splitting at Industrial Driven Current Density
Dhanasingh Thiruvengadam, Ravichandran Nithiasri, Muthukumaran Sangamithirai, Kaliyamoorthy Santhosh Kumar, Jayaraman Jayabharathi
Abstract
Pure-phase carbides suffer from mismatch in H 2 adsorption–desorption kinetics. Herein, we report on heterostructured CSNi 3 C/Fe 3 C@C/NFs-600 consisting of Co 3 C and Ni 3 C nanofibers embedded in a graphitic carbon shell synthesized by the electrospinning-magnesiothermic reduction (MTR) process. The Ni 3 C/Fe 3 C heterojunction core is encapsulated with a porous carbon shell having a large interfacial area, high conductivity, and more exposed active sites, which resulted in moderate hydrogen adsorption energy (E Hads ), increased desorption kinetics, and intriguingly efficient electron transfer. CSNi 3 C/Fe 3 C@C/NFs-600 exhibits low overpotentials (HER/OER) of 115/191 mV with a small Tafel slope of 56/53 mV dec –1 and a stability of over 60 h. The activation energy was calculated for electrolysis using CSNi 3 C/Fe 3 C@C/NFs-600 at 20.00 kJ/mol. The integrated area/number of active sites of CSNi 3 C/Fe 3 C@C/NFs-600 (4.60 × 10 –5 AV/5.730 × 10 16 ) confirmed MOOH* formation. The superaerophobicity was substantiated by fast gas bubble evolution from the catalyst surface. Using CSNi 3 C/Fe 3 C@C/NFs-600, we have produced H 2 efficiently with a lesser power consumption of 651.3 L H2 kW h –1 . The bifunctional electrolyzer of CSNi 3 C/Fe 3 C@C/NFs-600 (1.58 V) released vigorous gas bubbles compared to the benchmark electrolyzer of IrO 2 /Pt/C/NF (1.64 V) with great stability in alkaline solution. The synthetic strategy with catalyst properties demonstrated here provides perceptions into the future growth of robust bifunctional catalysts for scalable water splitting.