Handily etching nickel foams into catalyst-substrate fusion self‐stabilized electrodes toward industrial‐level water electrolysis

The key challenge of industrial water electrolysis is to design catalytic electrodes that can stabilize high current density with low power consumption(i.e.,overpotential),while industrial harsh conditions make the balance between electrode activity and stability more difficult.Here,we develop an efficient and durable electrode for water oxidation reaction(WOR),which yields a high current density of 1000 mA cm−2 at an overpotential of only 284 mV in 1M KOH at 25°C and shows robust stability even in 6M KOH strong alkali with an elevated temperature up to 80°C.This electrode is fabricated from a cheap nickel foam(NF)substrate through a simple one-step solution etching method,resulting in the growth of ultrafine phosphorus doped nickel-iron(oxy)hydroxide[P-(Ni,Fe)O_(x)H_(y)]nanoparticles embedded into abundant micropores on the surface,featured as a self-stabilized catalyst–substrate fusion electrode.Such self-stabilizing effect fastens highly active P-(Ni,Fe)O_(x)H_(y)species on conductive NF substrates with significant contribution to catalyst fixation and charge transfer,realizing a win–win tactics for WOR activity and durability at high current densities in harsh environments.This work affords a cost-effective WOR electrode that can well work at large current densities,suggestive of the rational design of catalyst electrodes toward industrial-scale water electrolysis.

Continuous Fe^(3+)releasing enabled complete reconstruction of Ni-based MOF for promoted water oxidation in industrial alkali

Most oxygen evolution reaction(OER)electrocatalysts show poor stability under industrial alkaline conditions(20–30 wt.%KOH).Therefore,it is essential to develop stable,efficient,and low-cost OER catalysts for industrial water electrolysis.Herein,we present a straightforward approach for the complete electrochemical reconstruction of Ni-BDC,a Ni-based metal-organic framework,for OER.This method involves the continuous release of Fe^(3+)from Fe foam counter electrode in a high-concentration(6.0 M,25 wt.%)KOH solution.The continuously Fe^(3+)releasing not only realizes in situ Fe^(3+)doping,but also introduces abundant defects in the obtained catalyst during cyclic voltammetry activation,thereby accelerating the electrochemical reconstruction.The reconstructed OER catalyst(Fe-doped nickel hydroxide/oxyhydroxide nanosheets supported on Ni foam,Fe-NiO_(x)(OH)y/NF)manifests a low overpotential of 217 mV at 10 mA cm^(-2)and 263 m V at 100 m A cm^(-2)in 1.0 M KOH.Noteworthy,the Fe-NiO_(x)(OH)_(y)/NF also demonstrates high stability in 30 wt.%KOH.This strategy of regulating the electrochemical reconstruction process sheds light on the construction of stable and efficient OER catalysts for industrial water electrolysis.