| As a clean and environmentally friendly resource,hydrogen energy receives great attention nowadays.Among many hydrogen production methods,the most effective is split water under the action of the electrocatalyst.It has the merits of good efficiency,high product purity,clean and pollution-free.HER is a two-electron rapid reaction process,while OER is a slow four-electron reaction process.Therefore,the kinetic speed of the OER process determines the efficiency of catalytic cracking water.In order to reduce energy consumption,it is important to construct an excellent catalyst for OER.At present,the precious metals Pt and RuO2 were state-of-the-art HER and OER catalysts,but the expensive cost and scarcity of resources seriously limit their largescale application.Therefore,many works have been studied for fabricating electrocatalysts with long life,low cost,high efficiency,and environment-friendly.However,large-scale electrolysis of water to produce hydrogen will put tremendous pressure on the already limited freshwater resources.Like most natural resources,they were splitting seawater to obtain hydrogen energy.It is also facilitated by seawater desalination.In this thesis,several transition metal phosphides were synthesized through a simple hydrothermal method and high-temperature calcination to study the overall seawater decomposition performance.The specific contents are as follows:(1)Through a simple hydrothermal method and phosphating annealing treatment,the P-doped bimetallic rod array structure composed of Co and Mo was prepared on foamed nickel(NF).The synthesized Co and Mo-based oxide/phosphide exhibited excellent HER electrocatalytic performance through the synergistic effect of metal oxide and phosphorus doping.Only an ultra-low overpotential of 162.8 mV was required to drive the catalyst to run at a current density of 100 mA cm-2.An amorphous layer of FeOOH was electrochemically deposited on the surface of the nanorods.The formed layered core-shell structure can expand the surface area to riveting,expose more oxyhydroxide active sites for OER catalysis,and resist the erosion of chloride ions.In the meantime,the effect of electrodeposition time on the performance of OER was explored in the experiment.The layered core-shell structure prepared with an electrochemical deposition time of 500 s can provide an overpotential of 240.8 mV at 100 mA cm-2.The experimental results showed that the formed heterostructure through phosphorus doping and electrodeposition could provide sufficient reaction sites,a shorter ion transport path,and more appropriate reaction product adsorption energy.(2)Herein,we used the NiO nanosheets synthesized with the hydrothermal method as a template to prepare NiCo precursors using a solvothermal method and phosphating treatment under the nitrogen atmosphere.The sea urchin-like Ni@NP@NCP(F/SO)nanostructured was prepared for use as the hydrogen evolution catalyst.The surface of the nanosheet structure that was grown with clustered nanoneedles has several merits:On the one hand,it has a loose and porous structure to contact the electrolyte and shorten the ion transmission distance.On the other hand,more active sites can be exposed to enhance the HER performance of the catalyst.DMF/DMSO has a great effect on the surface morphology,crystal grain size,and crystal growth in the process of hydrothermal process.The prepared catalyst requires only 139.2 mV of overpotential at 100 mA cm-2 in 1 M KOH.The test results show that as a promising and effective strategy,morphology control is widely implemented to change the coordination of surface atoms,thereby improving the intrinsic catalytic performance of composites.Figure:[22]Table:[7]Reference:[107]... |
