Synchronous Surface-Interface and Crystal-Phase Engineered Multifaceted Hybrid Nanostructure of Fe-(1T)-VSe2 Nanosheet and Fe-CoSe2 Nanorods Doped with P for Rapid HER and OER, Kinetics

Abstract

Two different nanostructures of two dissimilar highly-potent active electrocatalysts, P-dopped metallic-(1T)-Fe-VSe₂ (P,Fe-1T-VSe₂ ) nanosheet and P-dopped Fe-CoSe₂ (P,Fe-CoSe₂ ) nanorods are hybridized and integrated into a single heterostructure (P,Fe-(VCo)Se₂ ) on Ni-foam for high-performance water splitting (WS). The catalytic efficiency of VSe₂ nanosheets is first enhanced by enriching metallic (1T)-phase, then forming bimetallic Fe-V selenide, and finally by P-doping. Similarly, the catalytic efficiency of CoSe₂ nanorods is boosted by first fabricating Fe-Co bimetallic selenide and then P-doping. To develop super-efficient electrocatalysts for WS, two individual electrocatalysts P,Fe-1T-VSe₂ nanosheet and P,Fe-CoSe₂ are hybridized and integrated to form a heterostructure (P,Fe-(VCo)Se₂ ). Metallic (1T)-phase of transition metal dichalcogenides has much higher conductivity than the 2H-phase, while bimetallization and P-doping activate basal planes, develop various active components, and form heterostructures that develop a synergistic interfacial effect, all of which, significantly boost the catalytic efficacy of the P,Fe-(VCo)Se₂ . P,Fe-(VCo)Se₂ shows excellent performance requiring very low overpotential (η_HER = 50 mV@10 mAcm^-2 and η_OER = 230 mV@20 mAcm^-2 ). P,Fe-(VCo)Se₂ (+, -) device requires a cell potential of 1.48 V to reach 10 mA cm^-2 for overall WS.

Keywords: P-doping; overall water splitting; oxygen evolution reaction.