Splendid Intrinsic\nActivity of NiC/Mo<sub>2</sub>C@C\nNanocubes for Efficient Water Oxidation

Developing inexpensive, efficient\nelectrocatalysts for\nhydrogen\ngeneration gained much attention for water splitting. Herein, the\ninterface engineering concept was proposed to fabricate a corn husk\nbiomass-derived NiC/Mo<sub>2</sub>C@C-450 heterostructure consisting\nof NiC and Mo<sub>2</sub>C embedded in graphitic carbon synthesized\nby the mechanochemical calcination/magnesiothermic reduction strategy.\nThe NiC/Mo<sub>2</sub>C heterojunction encapsulated with porous carbon\nhaving more interfacial area and high conductivity with exposed catalytic\nsites leads to moderate hydrogen adsorption energy, improved desorption\nkinetics, and assisted rapid electron transfer. The optimum catalyst\nNiC/Mo<sub>2</sub>C@C-450 affords a low overpotential (GC/NF) of 291:258\nmV with a small Tafel slope of 117:103 mV dec<sup>–1</sup> and\nattains stability over 8 h. The activation energy was calculated for\nelectrolysis using NiC/Mo<sub>2</sub>C@C-450 as 44.00 kJ/mol. The\nintegrated area/number of active sites of NiC/Mo<sub>2</sub>C@C-450\n(4.97 × 10<sup>–5</sup> AV/9.98 × 10<sup>–3</sup>) confirmed MOOH* formation. The superaerophobicity was substantiated\nby fast gas bubble evolution from the catalyst surface. Using NiC/Mo<sub>2</sub>C@C-450, we have produced H<sub>2</sub> efficiently with a\nlower power consumption of 761.50 L<sub>H2</sub>kWh<sup>–1</sup>. The two-electrode configuration using NiC/Mo<sub>2</sub>C@C-450/NF//Pt/C/NF\nrequired a cell voltage of 1.60 V with great stability in an alkaline\nsolution. The intriguing synthetic strategy will provide a potential\navenue for synthesizing other metal carbide catalysts for extensive\nelectrochemical applications.