Control Synthesis Of Cobalt And Molybdenum Based Nanomaterials For Elecrocatalysis

It is essential to develop environmental-friendly device and clean energy to solve environmental pollution and greenhouse effect which are caused by the consuming of traditional fossil fuels.Fuel cell is a green and efficient device which attracted extensive attentions.However,the low reaction kinetics of ORR at the cathode and the feeding,storage of hydrogen impede the development of fuel cells.At present,Pt is the most effeicient catalyst,but the price and storage impede its large scale usage.Tarnsition metals are investigated extensively as catalysts due to its abundant resource.Based on the above problems,this dissertation are consisted of several sections based on cobalt and molybdenum compounds for electrocatalysis:?1?Melamine act as gelator to form cobalt based supramolecular gel and carbonized it to form double shelled Co@CoO@N-C/C catalysts for ORR.Both nitrogen and cobalt play important roles on improving the electrocatalytic activity for ORR.Furthermore,the prepared catalyst presents outstanding stability and methanol tolerance performance.The strategy is simple and environmental friendly which is suitable for large scale production.?2?MoP-RGO was prepared by solvothermal and high temperature phosphorized treatment which is a facile strategy relative to the traditional method.The prepared catalyst exhibits excellent catalytic activity for HER in both acid and alkaline media.RGO plays an important role on improving the conductivity,avoid the aggregation of nanoparticles and provide rich active sites.This work provides an efficient method to synthesize metal phosphides.?3?Three kinds of molybdenum compounds are prepared through solvothermal and high temperature treatments,which are investigated systemically for HER in both acid and alkaline media.MoP-C possesses outstanding catalytic activity for HER in acid medium,but Mo₂C presents the best catalytic performance in basic electrolyte.The research results can be used as a directory for the investigation of molybdenum based compounds on HER.?4?A facile one pot strategy was developed to synthesize heteroatoms doped carbon supported MoS₂-MoP-C nano sheets for HER,the prepared catalyst presents excellent catalytic activity and stability in acid electrolyte.The satisfactory catalytic performance can be attributed to several factors,including the heteroatoms doping,high surface area and the synergistic effect between P and S.This study provides a method to improve the catalytic activity of metal sulfides.?5?CoMoS prepared by solvothermal strategy and the prepared catalyst presents several features,including high surface area,3D porous structure,electron interactions between Co and Mo and rich defects.As a result,the prepared CoMoS exhibits outstanding catalytic activity for HER which has a low onset potential of 42 mV and low overpotential of 98 mV to deliver a current density of 10 mA cm^-2 in basic electrolyte.This section provides an efficient way to prepared outstanding catalyst for HER in alkaline electrolyte.