| As the consumption of fossil fuels continues to increase and the increasingly prominent problem of environmental pollution,people are made conduct in-depth research and development of alternative,clean and sustainable new renewable energy for the sake of realizing the sustainable development of the country and world.Thanks to its high energy density and zero emission when burded,hydrogen has been universally recognized as a potential renewable clean energy.However,the sustainable and green production of hydrogen is still faced with great challenges.Hydrogen production by electrolytic water decomposition is an environmental and sustainable way,which can decrease the dependence on fossil fuels and speed up the transformation of energy sources.Currently,low-cost,abundant storage and mechanically stable transition metals（TMs）are considered as a class of candidate materials to replace the most efficient catalysts for platinum-group noble metal based（PGM）catalysts,but how to further improve the electrocatalytic hydrogen precipitation performance of TMs,which has become the focus of researchers’attention and research.In this thesis,the ordered mesoporous nickel phosphide（OM-Ni2P）and lyotropic Mo S2 nanomicrospheres（Mo S2-NP）were designed and prepared by different strategies with the entry point of improving the exposed active sites,electrical conductivity and metal doping,respectively,and applied to the performance testing of electrolytic hydrogen evolution reaction（HER）.The details are as follows:（1）Ordered mesoporous OM-Ni2P catalysts with high specific surface area and abundant active sites with cubic Ia 3d symmetry were synthesized by nanocasting and tested for electrocatalytic hydrogen precipitation performance.It was shown that OM-Ni2P has outstanding hydrogen evolution performance in 0.5 M H2SO4,which is much better than that of disordered mesoporous citric acid assisted nickel phosphide（CA-Ni2P）,OM-Ni2P has an overpotential of 170 m V at the current density of 10 m A·cm-2,Tafel slope of 99 m V·dec-1 and favourable catalytic stability.The excellent catalytic hydrogen precipitation performance of OM-Ni2P is mainly derived from the fact that the ordered mesoporous structure not only serves as a transport channel,which promotes the full contact between H+in the electrolyte and the active sites of the electrocatalyst,accelerating the generation and release of H2 from the active sites,thus which will shorten the electrolyte diffusion path and reduce the charge transfer resistance;it also promotes the diffusion of P species generated from the thermal decomposition of Na H2PO2·H2O in the mesoporous pore channels,which in turn fully phosphorylates and generates a large amount of hydrogen precipitation active material,nickel phosphide,thus facilitating the dissociation of water.（2）Litchi-like Mo S2 nanomicrospheres（Mo S2-NP-x）catalysts enriched with 1T phase were synthesized by a solvothermal method and tested for electrocatalytic hydrogen precipitation performance,and the hydrogen precipitation performance of Mo S2-NP was improved by adjusting the temperature variables and cobalt（Co）doping.It was shown that temperature variation could change the catalytic activity of Mo S2-NP,with the HER performance of Mo S2-NP increasing first and then decaying with increasing temperature.At a solvent heat temperature of 180 oC,Mo S2-NP-180exhibited the best hydrogen precipitation performance,far exceeding that of Mo S2Nanoflower catalyst（Mo S2-NF）prepared by conventional hydrothermal method.Which has an overpotential was 249 m V at a current density of 10 m A·cm-2 and the Tafel slope was 94 m V·dec-1.Meanwhile,the prepared Co-doped lyotropic Mo S2-NP-180 nanomicrospheres（Co Mo S2-NP-180）exhibited excellent hydrogen precipitation performance and stability in 0.5 M H2SO4,with an overpotential of 202 m V at a current density of 10 m A·cm-2 and a small Tafel slope of 63 m V·dec-1.The excellent hydrogen precipitation performance of Co Mo S2-NP-180 was mainly attributed to the large specific surface area and the nano-dot array structure of Mo S2-NP-180.This provides the initial conditions for the excellent electrocatalytic hydrogen precipitation performance.At the same time,the doping of Co not only modulates the electronic structure of Mo S2-NP-180 and thus optimizes the hydrogen adsorption kinetics of the catalyst,but also adds some additional new active sites of Co,which facilitates the electron transport and thus contributes to the electrolytic hydrogen precipitation. |
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