Plasma-Assisted Synthesis of NiCoP for Efficient Overall Water Splitting

Abstract

Efficient water splitting requires highly active, earth-abundant, and robust catalysts. Monometallic phosphides such as NiP have been shown to be active toward water splitting. Our theoretical analysis has suggested that their performance can be further enhanced by substitution with extrinsic metals, though very little work has been conducted in this area. Here we present for the first time a novel PH plasma-assisted approach to convert NiCo hydroxides into ternary NiCoP. The obtained NiCoP nanostructure supported on Ni foam shows superior catalytic activity toward the hydrogen evolution reaction (HER) with a low overpotential of 32 mV at -10 mA cm in alkaline media. Moreover, it is also capable of catalyzing the oxygen evolution reaction (OER) with high efficiency though the real active sites are surface oxides in situ formed during the catalysis. Specifically, a current density of 10 mA cm is achieved at overpotential of 280 mV. These overpotentials are among the best reported values for non-noble metal catalysts. Most importantly, when used as both the cathode and anode for overall water splitting, a current density of 10 mA cm is achieved at a cell voltage as low as 1.58 V, making NiCoP among the most efficient earth-abundant catalysts for water splitting. Moreover, our new synthetic approach can serve as a versatile route to synthesize various bimetallic or even more complex phosphides for various applications.

Recent Progress on Layered Double Hydroxides and Their Derivatives for Electrocatalytic Water Splitting

“…Therefore, considering the effect of defects on the bimetal phosphide, we were wondering whether the defects of the bimetal phosphide would further enhance their OER or HER performance. As expected, Alshareef and co‐workers recently reported a novel PH 3 plasma‐assisted approach to convert NiCo LDHs into ternary NiCoP as a novel bifunctional electrocatalyst ( Figure 12 Aa) 94. The plasma technology can etch the surface of nanomaterials and bring different defects 168.…”

Dual‐Native Vacancy Activated Basal Plane and Conductivity of MoSe2 with High‐Efficiency Hydrogen Evolution Reaction

“…Simultaneously, the electrode kinetics of the catalysts can be obtained by the electrochemical impedance spectroscopy measurements from 100 kHz to 0.1 Hz. The fitted charge‐transfer resistance of R ct ≈ 8 Ω for MoSe 2 nanosheets is much smaller than that of 35 Ω for MoSe 2 nanoplates and 52 Ω for MoSe 2 microparticles (Figure S9a, Supporting Information), demonstrating the high electrode kinetics for MoSe 2 nanosheets. Furthermore, the effective electrochemical surfaces of catalysts could be evaluate by measuring the double layer capacitance ( C dl ) of the catalysts, where the calculated C dl for MoSe 2 nanosheets is 4.5‐fold and 2.2‐fold higher than that of MoSe 2 micro‐particles and nanoplates, respectively, indicating its larger electrochemical surface area (Figure S9b, Supporting Information).…”

A Surfactant‐Free and Scalable General Strategy for Synthesizing Ultrathin Two‐Dimensional Metal–Organic Framework Nanosheets for the Oxygen Evolution Reaction

“…To summarize,as eries of ultrathin MOF-74 nanosheets with abundant coordinatively unsaturated metal sites are synthesized through coordination assisted 2dOSA from their corresponding M-ONS,w hich cannot be obtained from the [39] a-CoSe/ Ti, [40] Co 9 S 8 /NOSC, [41] CoFePO, [42] CoP/NC, [43] CoNiP, [44] Ni-NiP, [44] Ni@NC-800/NF, [45] NiFeO x /CNF, [46] NiMo, [47] NiS/NF, [48] NiSe/NF, [49] N-Ni 3 S 2 -NF, [50] and Ni 5 P 4 . [51] delamination of their bulk counterparts or the conventional solvothermal method.…”