Preparation And Performance Study Of Nanoporous Nickel-based Water Electrolysis Catalyst In Eutectic Solvent

With the rapid development of economy,excessive use of fossil fuels along with the increasing demand for energy has caused serious energy and environmental problems.And the search for clean,efficient and sustainable energy is pressing.Hydrogen as the ideal energy carrier prepared by electrocatalysis water,which is one of methods for production the high-purity hydrogen,including the hydrogen evolution reaction at the cathode?HER?and the anodic oxygen evolution reaction?OER?,is considered to be a promising technology.However,the sluggish reaction kinetics for electrolytic water splitting process requires high overpotentials to drive the two-half reactions,leading to a much larger operating cell voltage for practical overall water splitting.To promote the overall water splitting,efficient electrocatalysts are necessary to decrease the reaction overpotentials,thus making the splitting process more energy-saving.At present,the best electrocatalysts are still precious metal catalysts,such as Pt,Ru O₂,Ir O₂,etc,whichare precluded from large-scale use for their reserve scarcity and high price.Therefore,the development of highly efficient electrocatalytic materials based on earth-abundant elements,low cost and eco-friendly as a substitute for these noble metal based catalysts has become eagerly desired in various countries.Nickel-based alloys,as the most promising alternative materials,are generally used as highly active and low-cost electrocatalyst materials in alkaline electrolytes.In this paper,the highly active Ni-based alloy catalysts material was designed by one-step electrodeposition method in deep eutectic solvents based ethaline.The specific contents include the following three aspects:?1?The porous nickel-copper alloy nanosheets preparated by one-step electrodeposition approach for the hydrogen evolution reaction;?2?According to the deficiencies of nickel-copper alloy materials for the hydrogen evolution reaction,and to further optimize the catalytic performance,prepared nanoporous microspheres nickel-molybdenum alloy electrocatalysts as the bifunctional catalyst for overall water splitting;?3?In-situ growth the 3D nanoporous architectures amorphous nickel-iron-sulfur catalyst on a highly conductive substrate for oxygen evolution reaction to make up for the shortcomings of nickel-molybdenum alloy materials.?1?The electrodepositedp orous nickel-copper alloy nanosheets electrode material on the copper substrate exhibits good catalys performance in alkaline solution with a small Tafel slope of 57.2 m V/dec and a low onset potential of-48 m V?vs.RHE?.To achieve 10 m A cm^-2 and 20 m A cm^-2 need only deliver overpotentials of-128 m V and-150 m V.However,the long-term stability is poor.After long-term stability test of10000 s for hydrogen evolution reaction,the performance degraded about 36%.?2?The electrodeposited nanoporous nickel-molybdenum alloy microspheres on the copper substrate exhibited higher bifunctional electrocatalytic p erformance with a small Tafel slope of 49 and 108 m V?vs.RHE?and to deliver 20 m A cm^-2 need overpotential of-63 and 335 m V?vs.RHE?,respectively,for hydrogen evolution reagtion and oxygen evolution reaction in 1.0 M KOH solution.The assembled two-electrode water electrolysis system requires only 1.59 V for driving 10 m A cm^-2,and has a negtively decay after a long-term stability test of 110 h.?3?In-situ growth self-supporting three-dimensional nanoporous architectures amorphous nickel-iron-sulfur catalyst materials for oxygen evolution reaction,with overpotentials of only 260 and 285 m V required for 100 and 500 m A cm^-2,have exceeded the catalytic performance of Ru O₂.In a two-electrode water electrolysis system composed of the nickel-molybdenum alloy,the current densities of 10 and 100m A cm^-2 can be responsed of 1.52 V and 1.79 V in 1.0 M KOH solution.Surprisingly,deliver 100 m A cm^-2 requires only 1.69 V with a long durability of 220 h in the 30 wt%KOH solution,.