| Hydrogen production by electrolysis of water is a promising way to produce hydrogen on a large scale,which can convert electricity to hydrogen,save fossil fuels and avoid environmental pollution.Conventional precious metal catalysts loaded on carbon carriers are not only expensive to use,but also easily corrode during the catalytic process,leading to degradation of catalytic performance.Therefore,the development of highly active,inexpensive,and stable catalysts is of great importance for the long-term stable operation of hydrogen production from electrolytic water.The metal in the metal oxide is in a high oxidation state,is not easy to lose electrons and be further oxidized,and has higher corrosion resistance than carbon in the electrochemical environment.In this paper,titanium dioxide,which is abundant in resources,low cost,and good chemical stability,is used as the catalyst carrier.The conductivity of titanium dioxide is improved using elemental doping and constructive defects,and it was applied to the electrolytic water reaction by loading metals.The influence of the interrelationship between the metal catalyst and the titanium dioxide carrier on the catalytic activity and stability was investigated.The main research contents and results of this thesis are as follows:（1）Efficient electrocatalysts with strong interactions,Ru@N-Ti O2/C,were prepared by homogeneously loading ruthenium on nitrogen and carbon modified mesoporous titanium dioxide using the impregnation method.The ruthenium particles supported on nitrogen and carbon modified titanium dioxide are more easily oxidized than those supported on unmodified titanium dioxide.It can make the electron transfer from the ruthenium nanoparticles to the nitrogen and carbon doped mesoporous titania easier,thus enhancing the metal-carrier interaction.The prepared Ru@N-Ti O2/C catalyst exhibited excellent HER performance in the full p H range,especially in 1 M KOH with an overpotential as low as 39 m V@10 m A cm-2 and a Tafel slope of 47 m V dec-1,which even surpassed the Pt/C catalyst.Meanwhile,the Ru@N-Ti O2/C catalyst also has low overpotentials of only 82 m V and 116 m V in 1.0 M PBS and 0.5 M H2SO4at a current density of 10 m A cm-2,comparable to the Pt/C catalyst.（2）With the help of the Ti-MOF（MIL-125）which has periodic porous structure,high specific surface area and high thermal stability,a certain amount of ruthenium and nickel was introduced at the early stage of MIL-125 growth to obtain a MIL-125precursor containing trivalent ruthenium ions and divalent nickel ions,and the Ni Ru-Ti O2/C electrocatalyst was prepared by pyrolysis.After hydrogen reduction treatment,oxygen vacancies were introduced in the carrier to promote electron transfer between Ni Ru particles and Ti O2/C.Overpotentials of 40 m V and 80 m V were required to obtain a current density of 10 m A cm-2 in 1 M KOH and 0.5 M H2SO4,respectively.After 1000cycles of CV cycling test,the current density of Ni Ru-Ti O2/C catalyst almost did not decay,which proved that the prepared Ni Ru-Ti O2/C catalyst has excellent HER performance under acidic and alkaline conditions.（3）Non-precious metal elements are widely favored by researchers because of their abundant resources in nature,low usage cost and good electrical conductivity.Fe Co Ni trimetallic doped MIL-125 was prepared using hydrothermal method,and Ti O2/C@Fe Co Ni phosphide electrocatalysts were obtained after pyrolysis and phosphorylation.The Ti O2 obtained by the pyrolysis of MIL-125 has high specific surface area and pore volume,which can provide more active sites and is favorable for charge transport.After phosphorylation,the synergistic effect between Fe Co Ni trimetals is further enhanced,which makes the catalyst have better oxygen precipitation performance under alkaline conditions.The current density of the catalyst reached 10m A cm-2 in 1 M KOH solution at an overpotential of 306 m V.After 1000 CV cycles,the current density almost did not decay and could run stably for 20 h. |
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