Electronic structure modification and N-doped carbon shell nanoarchitectonics of Ni₃FeN@NC for overall water splitting performance evaluation

Improvement of the sluggish kinetics of the overall water splitting catalyst through N-doping and the formation of a carbon shell makes it possible to achieve carbon neutrality and to synthesize catalysts that can replace noble metals. Surprisingly, in Ni₃FeN@NC catalysts, transition metals received an extra electron due to doping with the nitrogen element, and thus the electron distribution probability at the Fermi energy level increased. In addition, pyridinic-N in the N-doped carbon shell can contribute to the improvement of catalyst performance. Density functional theory (DFT) calculations demonstrated the electrical performance by specifying the model of Ni₃FeN@NC and were able to elucidate the mechanism of the catalytic reaction (OER and HER). The OER and HER overpotentials of the synthesized Ni₃FeN@NC were confirmed to be 246 mV and 181 mV at 10 mV cm⁻² in 1.0 M KOH. It was proved that 98% of the performance was maintained even in overall water splitting performed for 24 h.