Synergistic Nanotubular Copper‐Doped Nickel Catalysts for Hydrogen Evolution Reactions

Abstract

Developing highly active electrocatalysts with low cost and high efficiency for hydrogen evolution reactions (HERs) is of great significance for industrial water electrolysis. Herein, a 3D hierarchically structured nanotubular copper-doped nickel catalyst on nickel foam (NF) for HER is reported, denoted as Ni(Cu), via facile electrodeposition and selective electrochemical dealloying. The as-prepared Ni(Cu)/NF electrode holds superlarge electrochemical active surface area and exhibits Pt-like electrocatalytic activity for HER, displaying an overpotential of merely 27 mV to achieve a current density of 10 mA cm and an extremely small Tafel slope of 33.3 mV dec in 1 m KOH solution. The Ni(Cu)/NF electrode also shows excellent durability and robustness in both continuous and intermittent bulk water electrolysis. Density functional theory calculations suggest that Cu substitution and the formation of NiO on the surface leads to more optimal free energy for hydrogen adsorption. The lattice distortion of Ni caused by Cu substitution, the increased interfacial activity induced by surface oxidation of nanoporous Ni, and numerous active sites at Ni atom offered by the 3D hierarchical porous structure, all contribute to the dramatically enhanced catalytic performance. Benefiting from the facile, scalable preparation method, this highly efficient and robust Ni(Cu)/NF electrocatalyst holds great promise for industrial water-alkali electrolysis.

Implanting Ni-O-VOx sites into Cu-doped Ni for low-overpotential alkaline hydrogen evolution

“…This results in the weakened H-adsorption on Cu-doped Ni(111) and thus the enhanced HER activity. Noted that Cu-doped Ni has advantage over Ni, because of the weaker binding of H* on Cu compared to that on Ni 34 . After exposing the Ni(Cu)VOx electrode to KOH electrolyte for HER, the physically absorbed and weakly bonded VOx on the electrode surface is dissolved into the electrolyte ( Fig.…”

Ultralow FeIII Ion Doping Triggered Generation of Ni3S2 Ultrathin Nanosheet for Enhanced Oxygen Evolution Reaction

“…To measure electrochemical capacitance, a series of CVs were performed across −0.05 V∼0.05 V of the open‐circuit potential at scan rates of 5, 10, 25, 50, 100 and 200 mV s −1 . The slope of the charging current ( i c ) as a function of the scan rate ( ν ) gives a straight line with the slope equal to the double layer capacitance ( C DL ), a specific capacitance ( C s ) value (0.040 mF cm −2 ) in 1.0 M KOH ,. The turnover frequency (TOF) values of electrodes are calculated according to the equation: TOF= j *A/(4Fn), where j is the current density at the overpotential of 300 mV, A is the area of the electrode, F is the Faraday constant (a value of 96485 C mol −1 ), and n is the number of moles of the active materials deposited onto the nickel foams ,.…”

“…The slope of the charging current (i c ) as a function of the scan rate (ν) gives a straight line with the slope equal to the double layer capacitance (C DL ), a specific capacitance (C s ) value (0.040 mF cm À 2 ) in 1.0 M KOH. [32,33] The turnover frequency (TOF) values of electrodes are calculated according to the equation: TOF = j*A/(4Fn), where j is the current density at the overpotential of 300 mV, A is the area of…”

Nickel Foam‐Supported Amorphous FeCo(Mn)−O Nanoclusters with Abundant Oxygen Vacancies through Selective Dealloying for Efficient Electrocatalytic Oxygen Evolution

“…The well-designed structural defects can not only create highly active sites for water adsorption and activation, but also supply spatially channels for mass and electron transfer. [10] Up to date, selective dissolution, [11][12][13] chemical solution/vapor reduction [14][15][16][17] as well as plasma or flame-engraving techniques [18,19] have been subsequently adopted to fabricate diversiform interface deficiencies and oxygen vacancies. For example, the abundant oxygen deficiencies in ultrathin metal hydr(oxy)oxides nanosheets have well-tailored the coordination environment and electronic structure of the coordinately unsaturated metal sites.…”