The Construction Of Transition Metal Element Nanomaterial Electrodes And Its Electrochemical Application

With the increase in energy demand and the energy and environmental problems brought about by the consumption of fossil energy,the governments have issued relevant policies successively to promote the development of clean energy and the transformation of energy production routes.The Shandong Provincial People's Government also announced the implementation plan for major projects of new and old kinetic energy conversion,highlighting the basic,leading and strategic role of new energy and new materials,and vigorously developing renewable energy.Hydrogen as a clean energy has attracted more and more attention.The electrolyzed water is currently the most clean and environmentally friendly hydrogen production pathway,and efficient catalysts are particularly important for the widespread implementation of this method.Transition metal nanomaterials have been studied more and more in related fields at home and abroad due to their excellent electrochemical properties,and have potential application prospects in energy production,storage and sensing.For example,such materials can be used as efficient catalysts for hydrogen production from electrolyzed water,and on the other hand,in biosensing applications,and detection of hydrogen peroxide.This research topic will focus on this aspect,design and prepare several transition metal material electrodes and explore their electrochemical applications.The main research contents are as follows:?1?The copper phosphide-cobalt phosphide hybrid nanowire array grown on carbon cloth?Cu₃P-CoP/CC? was prepared by hydrothermal method and temperature phosphating technology and the performance of hydrogen evolution reaction?HER?was investigated.Cu₃P-CoP/CC only needs an overpotential of 59 mV to drive a current density of 10 mA cm^-2 in 0.5 M H₂SO₄,which is superior to most acidic HER catalysts.Meanwhile,such catalyst also shows good electrochemical stability and maintain its catalytic activity for at least 15 hours.?2?The effect of elemental doping on the HER performance of phosphide was investigated.First,an aluminum-nickel double metal hydroxide?AlNi-LDH/TM?was prepared on a titanium mesh,and then an aluminum-doped nickel phosphide nanosheet array?Al-Ni₂P/TM?was prepared by low temperature phosphating.Such catalyst achieves a current density of 10 mA cm^-2 in 1.0 M KOH requiring only an overpotential of 129 mV,which is 47 mV less than pure Ni₂P.In addition,this catalyst can maintain its catalytic stability for at least 20 hours at an overpotential of 158 mV.?3?Mn-based materials are generally reported to be used as water oxidation catalysts,while Mn is also rich in reserves and low in price,so we consider whether it can be used as a dopant to improve the catalytic performance of catalysts.In this work,we obtained a Mn-doped nickel sulfide nanosheet array grown on a foamed nickel substrate?Mn-Ni₃S₂/NF? by two steps of hydrothermal preparation.It is verified by experiments that Mn-Ni₃S₂/NF reaches a current density of 10 mA cm^-2 in 1.0 M KOH and only requires an overpotential of 152 mV.Mn can be used as a dopant to enhance the catalytic performance of the catalysts.?4?In addition to the development of new energy sources,exploring green and sustainable energy production methods is also an important means to alleviate the fossil fuel energy crisis and environmental pollution problems.Ammonia is widely used in the production of fertilizers,explosives,crops and pharmaceuticals.It is great importance to the social economy.At present,the ammonia production method is mainly rely on the Haber method.This method needs to consume huge energy and accompanying carbon dioxide emission.In this background,electrochemical nitrogen reduction?NRR?is regarded as a promising method for producing ammonia.In this work,we prepared chromium oxide nanofibers?Cr₂O₃ NF? by electrospinning combined with high-temperature calcination.Such Cr₂O₃ NF presents good NRR selectivity and excellent performance.In 0.1 M HCl,Cr₂O₃ NF achieves a Faraday efficiency of 8.56%,which is better than most of the reported NRR catalysts.?5?Self-supported MoS₂ nanosheet arrays?MoS₂/CC?were prepared by one-step hydrothermal method and applied to H₂O₂ detection.Various characterizations were used to demonstrate the synthesis of materials.The MoS₂/CC electrode exhibits excellent selectivity and sensitivity in the detection,and the linear range of H₂O₂ concentration detection is 0.005-3.0 mM,the detection limit is 0.03?M,and the sensitivity is 5337.5?A mM^-1 cm^-2.This indicates that the self-supported nanoarrays based of transition metal elements has a promising application prospect in sensing.