Bimetallic Ni–Mo nitride nanotubes as highly active and stable bifunctional catalysts for full water splitting are favorably comparable to the performance of Pt/C and IrO2.
Metal–organic frameworks (MOFs) with intrinsically porous structures and well‐dispersed metal sites are promising candidates for electrocatalysis; however, the catalytic efficiencies of most MOFs are significantly limited by their impertinent adsorption/desorption energy of intermediates formed during electrocatalysis and very low electrical conductivity. Herein, Co is introduced into conductive Cu‐catecholate (Cu‐CAT) nanorod arrays directly grown on a flexible carbon cloth for hydrogen evolution reaction (HER). Electrochemical results show that the Co‐incorporated Cu‐CAT nanorod arrays only need 52 and 143 mV overpotentials to drive a current density of 10 mA cm−2 in alkaline and neutral media for HER, respectively, much lower than most of the reported non‐noble metal‐based electrocatalysts and comparable to the benchmark Pt/C electrocatalyst. Density functional theory calculations show that the introduction of Co can optimize the adsorption energy of hydrogen (ΔGH*) of Cu sites, almost close to that of Pt (111). Furthermore, the adsorption energy of water (ΔEH2O) of Co sites in the CuCo‐CAT is significantly lower than that of Cu sites upon coupling Cu with Co, effectively accelerating the Volmer step in the HER process. The findings, synergistic effect of bimetals, open a new avenue for the rational design of highly efficient MOF‐based electrocatalysts.
Development of noble-metal-free
and active electrocatalysts is
crucial for the oxygen evolution reaction (OER) in the water-splitting
process. Herein, crystal Co
x
B catalysts
(x = 1–3) of the OER are fabricated by a ball-milling
method. Among these Co
x
B catalysts, Co2B exhibits the best OER activity, with a current density of
10 mA cm–2 at an overpotential of 287 mV in 1 M
KOH solution. Such OER activity of Co2B is favorably comparable
to that of the commercial IrO2 and most recently reported
OER catalysts. Furthermore, the Co2B catalyst exhibits
excellent stability with a stable current density of 50 mA cm–2 over 12 h of continuous electrolysis operation. X-ray
photoelectron spectroscopy and cyclic voltammetry demonstrate that
the B in Co
x
B makes oxidation easier,
leading to their enhanced OER activities in comparison to metal Co.
In addition, the Co2B electrocatalyst also exhibits high
activity in the hydrogen evolution reaction; thus, the catalyst can
be used as a bifunctional catalyst for full water splitting.
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