Preparation Of Cobalt-Based Metal Materials Based On Heteroatom Regulation And Its Application In Oxygen Evolution Reaction

With the rapid development of the global economy,the gradual consumption of fossil fuels and the dramatic increase in carbon emissions has caused the global energy shortage and environmental pollution,which has increasing the demand for high-quality fuels.As an ideal clean energy with high energy density,pollution-free and abundant reserves,hydrogen energy has attracted widespread attention from researchers.Among them,electrocatalytic water splitting to produce hydrogen is an important way to acruire hydrogen energy.The electrocatalytic water splitting is a combination of semi-reactions that occurs on two electrodes.That is,hydrogen evolution reaction（HER）at the cathode and oxygen evolution reaction（OER）at the anode.Efficient electrocatalysts offen generate high current density at low potentials.Presently,the main obstacles of water electrolysis reaction are the slow reaction kinetics and excessive potential demands in electron transfer.The platinum（Pt）and platinum-based catalysts perform best in HER up to now,as wellas ruthenium（Ru）and iridium（Ir）-based oxide catalysts in OER.However,the low earth reserves,high economic costs,and insufficient electrochemical performance of precious metal catalysts have limited its practical applications in large-scale.Therefore,the design and development of bifunctional non-precious metal-based electrocatalytic materials with high catalytic activity,rich and stable earth reserves have become particularly important.Among the reported literatures,transition metal-based catalysts（including phosphides,sulfides,selenides,borides,nitrides,carbides,hydroxides,etc.）have been illustrated to be capable replaced catalyst in electrocatalytic water splitting in the future.In this work,the composition and morphology of cobalt-based metal nanomaterials were adjusted by heteroatom incorporation and in-situ nitridation.A series of electrolytic catalysts were prepared and the performance of electrocatalytic water splitting is explored.The main contents are as follows:1.Prussian blue analogues derived Co Fe-B nanocubes as enhanced oxygen evolution electrocatalysts.Herein,Prussian blue analogues derived Co Fe-based nanomaterials with increased specific surface area and abundant catalytic active sites are utilized as efficient and durable electrocatalysts for OER.Due to the adjustable chemical conformation and controllable three-dimensional morphology,Co Fe-B nanocubes exhibit ultra-thin nanosheets wrapped nanocube structure with excellent electrocatalytic performance and remarkable reaction kinetics in 1.0 M KOH aqueous solution.In addition,Co Fe-B nanocubes cost overpotentials of 261 and 338 m V at corresponding current densities of10 and 200 m A cm^-2,respectively,with small Tafel slope of 61 m V dec^-1 for OER,which behaves the higher catalytic capability than the reported commercial Ru O₂.2.Copper regulated cobalt-based nanomaterials for efficient electrocatalytic oxygen evolution reaction.The Cu-Co₂F₃N nanoneedle materials with abundant catalytic activity sites was used as efficient OER electrocatalyst after the precursor of copper regulated cobalt hydroxide supported on nickel foam substrate was placed in the downstream and the ammonium fluoride in the upstream of tube furnace for high-temperature interaction.Cu-Co₂F₃N-0.05 was found to be the catalyst with best OER performance by exploring the influence of copper consumption on the catalytic performance of cobalt-based nano needle-like material.The Cu-Co₂F₃N-0.05 nanomaterials cost overpotentials of 202 and241 m V at corresponding current densities of 50 and 400 m A cm^-2,respectively,with small Tafel slope of 42 m V dec^-1 for OER.The results show that Cu-Co₂F₃N-0.05nanoneedles-like materials can be successfully prepared and shows favorable oxygen evolution performance.