Fabrication of MoS₂‐Decorated Nickel‐Cobalt Bimetal Phosphide Nanocubes as Efficient Electrocatalysts for Hydrogen Evolution

Abstract

Nickel‐cobalt bimetal phosphides were prepared via the phosphidation treatment of NiCo‐based Prussian blue analogue (PBA). Subsequently, the core‐shell structures of NiCoP@MoS2 were successfully assembled through a solvothermal reaction, where the NiCoP substrates were uniformly and randomly covered by MoS2 nanosheets. The resulting hybrids exhibited significantly superior catalytic activities towards hydrogen evolution reaction (HER) in 0.5 M H2SO4 to bare MoS2. The optimal catalyst afforded the best HER performance with a low overpotential of 138 mV at 10 mA cm−2 and Tafel slope of 78.1 mV dec−1, together with high stability and durability. The excellent HER properties of hybrids mainly originated from the unique core‐shell architecture and the intrinsic natures of MoS2 and PBA‐derived bimetal phosphides.

Core‐Shell Structured CoP@MoS2 Electrocatalysts for Enhanced Hydrogen Evolution Reaction

“…After the initial unstable stage, the current density exhibited a slight degradation after a long period of 16 hours, demonstrating an excellent operational stability under the given condition. The time‐dependent current density curves with similar shapes have been also observed in other HER electrocatalysts . Furthermore, the LSV curves before and after 3000 cycles were basically overlapped, demonstrating the excellent stability of the CoP‐350@MoS 2 catalyst.…”

“…Our current study is to further exolore HER properties of other hybrids combining MoS 2 and suitable substrates with high conductivity and intrinsic catalytic activity. Nowadays, transition metal phosphides (TMPs) have attracted much attention benefiting from their good conductivity and inherent catalytic activities . In fact, TMPs are an intermetallic compound with metal properties formed by P atom entering the lattice of transition metal.…”

Cobalt‐Molybdenum Bimetal Phosphides Encapsulated in Carbon as Efficient and Durable Electrocatalyst for Hydrogen Evolution

“…The mesoporous structure for Co-Mo-P@C originate from the maintenance of template structure, which might afford abundant active sites for the electrocatalytic process. [6] X-ray photoelectron spectroscopy (XPS) was employed to investigate the chemical state of Co-Mo-P@C. As shown in Figure S11, the XPS survey spectrum of Co-Mo-P@C manifested that Co, Mo, P, C, O, N elements were existed. The atomic ratio of Co : Mo : P is 22 : 1 : 33.…”

“…The peaks at 228.0 and 231.1 eV in Mo3d spectrum belonged to Mo 3d 5/2 and Mo 3d 3/2 orbitals, which can be attributed to Mo δ + (0 � δ � 4) species, confirming the existence of MoP and CoMoP 2 . [6,27] The high oxidation state of Mo 6 + (232.4 and 235.5 eV) in Co-Mo-P@C may arise from the surface oxidation due to air contacting. [28,29] Peaks centered at binding energy of 228.0 and 231.1 eV in Mo 3d region and 129.7 eV in P 2p region (P 2p 3/2 ) are typical peaks for MoP.…”

“…Therefore, it is critical to find a low-cost, high activity and long-time stability HER catalysts to replace precious metal-based materials. [5,6] The transition metals based compounds including phosphides, chalcogenides, borides, nitrides, carbides, and alloys, [7,8] have been identified as promising electrocatalysts to replace of the noble metal, because of their incompletely filled d orbitals for readily giving and taking electrons. [9] Among them, transition metal phosphides (TMPs) have been investigated and regarded as the promising catalysts toward HER [10,11] due to their unique charged natures (positive and negative charges in metal and phosphorus, respectively), and hydrogenase-like catalytic mechanism.…”