MOF-derived MoC-Fe heterojunctions encapsulated in N-doped carbon nanotubes for water splitting

Abstract

Engineering the synergistic interfacial structures in nanostructured electrocatalysts is an effective yet challenging pursuit. Here we report porous nitrogen-doped carbon nanotubes (NCNTs) entrapping heterojunctions between carbide and transition metal nanoparticles (NPs) as excellent bifunctional catalyst for hydrogen and oxygen evolution reactions (HER and OER). Dual-phase MoC and Fe NPs confined in NCNTs (denoted as MoC-Fe@NCNTs) was fabricated by trapping [Fe(C2O4)3]3– into Zn/Mo-HZIF framework followed by pyrolysis. The resultant catalyst exhibited commendable bifunctional activities with small overpotentials at 50 mA cm−2 for the HER of 252 and OER of 304 mV, respectively. Theoretical calculations and experimental observation prove that the combination of Fe NPs generates synergistic heterointerfaces and improves OER activity of MoC, thus endowing outstanding bifunctional electrocatalytic performances. Moreover, the NCNTs, as the electronic communication amplifier, can facilitate electron transfer and inhibit the aggregation and corrosion of the active species. The controllable fabrication of MOF-derived heterostructures reported in this work provides a prospect for developing bifunctional MOF derivatives for water electrolysis.