| In recent years,hydrogen,as a new type of green fuel and renewable energy,has been extensively studied to improve environmental pollution and energy consumption problems.Hydrogen energy generated by electrochemical cracking water has become a current research hotspot.Due to the high cost of precious metals,it is an effective way to study various non-precious metal-based electrocatalysts to replace platinum for hydrogen production.The synergy and electronic configuration between transition metal compounds and conducting polymers can enhance the conductivity of the active site,thereby accelerating the catalytic process of hydrogen evolution reaction（HER）.In this paper,nanocomposites with high electrical conductivity and long-term stability are prepared by compounding various transition metal compounds with polyindole.A series of characterizations and electrochemical tests are carried out to explore the electrocatalytic properties of the as-prepared nanocomposites,and to explore the application prospects of nanocomposites in the field of electrocatalysis.1.The Mo2C/C nanocomposite with a PIn-derived carbon layer as the outer shell and molybdenum carbide crystals inside was prepared by using phosphomolybdic acid(PMo12)to initiate the polymerization of indole（PIn）in chemical polymerization and thermal quenching.The conductive Mo2C/C structure ensures the electron transfer and ion transport process,and promotes the kinetic process of hydrogen molecule generation.The polyindole-derived carbon materials can effectively increase the surface area and enrich the active catalytic sites,and suppress the agglomeration of Mo2C nanocrystals.The prepared Mo2C/C nanocomposites exhibited excellent HER electrocatalytic activity and stability.With an overpotential of 165 m V in acidic media,the overpotential is only 234 m V at current densities up to 100 m A cm-2.In alkaline medium,it has an overpotential of 142 m V at 10 m A cm-2,and a Tafel slope of 87.5m V dec-1.At the same time,the electrocatalyst has small charge transfer resistance and long-term stability in both acid and alkaline solutions.Considering the simplicity,scalability,and excellent catalytic performance of the synthetic method,this study opens a new avenue for designing various novel low-cost high-performance electrocatalysts.2.Phosphorus-doped tungsten carbide coated nitrogen-doped carbon（P-W2C/NC）nanocomposites were synthesized via green redox reaction and carbonization process.In this synthesis process,phosphotungstic acid-polyindole/reduced graphene oxide(PW12-PIn/r GO)was first used as a precursor,followed by carbonization to form P-W2C/NC nanocomposites.The intercalation of r GO and the polymerization of PIn form a conductive polymer framework that prevents W2C nanoparticles from agglomerating,thus providing a larger surface area.The synthesized P-doped W2C nanomaterials are uniformly embedded in the composite framework with more exposed sites.The P-W2C/NC electrocatalyst exhibits remarkable electrocatalytic activity in the hydrogen evolution reaction,reaching a current density of 10 m A cm-2in 0.5 M sulfuric acid with a low overpotential of 89 m V and a Tafel slope of 93 m V dec-1;Achieving a current density of 10 m A cm-2 in an alkaline environment requires an overpotential of 133 m V and the current loss in long-term tests is only 23%.Furthermore,the catalyst exhibits high electrochemical surface area and excellent conductivity due to the synergistic effect of N-doped carbon with W2C and the rich active network formed.This study opens a new avenue for the design and synthesis of novel nanostructured electrocatalysts and provides a new direction for exploring tungsten-based electrocatalysts.3.In this experiment,the polyindole/molybdenum disulfide（PIn/Mo S2）nanocomposite with excellent HER performance was prepared by a one-step hydrothermal strategy.The key to synthesizing efficient molybdenum disulfide electrocatalysts is to construct rational composite architectures to improve their stability,reduce aggregation,and enhance their inherently low electrical conductivity.The best-performing HER electrocatalyst was obtained by optimizing the mass and temperature with indole and ammonium molybdate as reactants,and the synergistic effect enhanced the intrinsic catalytic activity of PIn/Mo S2.Due to the high surface area,hierarchical nanostructure,and enhanced charge transport function of the nanocomposite,the PIn/Mo S2 electrode exhibits good electrocatalytic performance in acidic solution.When the current density is 10 m A cm-2,the overpotential of the hydrogen evolution reaction is 125 m V,and the Tafel slope is 62.8 m V dec-1.With a charge transfer resistance of 6.3Ωand an electric double-layer capacitance of 16.75m F cm-2,these properties make PIn/Mo S2 promising high-performance electrocatalyst.The PIn/Mo S2 nanocomposite effectively facilitates the charge transmission and changes the electronic structure,thereby enabling a more efficient HER process.This study sheds light on the design of efficient,stable,and low-cost HER electrocatalysts. |
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