Synthesis Of V/P-CN,Mo/MTP Oxidative Desulfurization Catalysts And Cobalt Phosphate Hollow Microsphere OER Electrocatalyst Based On Organophosphonic Acid

Overconsumption of fossil fuels has triggered energy and environmental crisis.As a core component of fossil fuels,petroleum will continue to be the main source of energy for the development of human society in the coming decades.The consumption of sulfur-containing compounds in petroleum will produce SO_x and inevitably lead to severe environmental pollution and even threaten human health.Oxidative desulfurization（ODS）technology has been regarded as one of the most promising desulfurization methods,because it can achieve high efficiency and ultra-deep desulfurization under mild conditions.In addition,the development of new energy conversion and storage technologies such as water splitting,fuel cells,and metal-air batteries to replace traditional fossil fuels can be a research hotspot currently to solve energy and environmental crises.However,oxygen evolution reaction（OER）with a sluggish kinetic limits the large-scale development of the above applications.Organophosphonic acid has unique physical and chemical properties,cost-effective prices and abundant reserves,can chelate with metal ions,which has great potential in the synthesis of multifunctional mesoporous materials.This thesis aims to synthesize novel and efficient energy and environmental catalytic materials based on organophosphonic acid,the addition of organophosphonic acid modifer and the design of metal phoshponates support have been used to prepare V/P-CN and Mo/MTP ODS catalysts,respectively,and the metal phosphonate-derived strategy has been applied in the preparation of OER electrocatalyst.According to a series of characterizations and experimental results,the reaction mechanism was reasonably deduced.The specific content includes the following three aspects:1.Phosphorus-doped graphitic carbon nitride（g-C₃N₄）nanosheets with atomic dispersed V-based nanocomposites（V/P-CN）were fabricated through a facile organophosphonic acid-modified co-condensation route.Firstly,adequate amounts of melamine,organophosphonic acid,and NH₄VO₃ are thoroughly mixed.The organophosphonic acid is intensely coupled with melamine through acid-base interaction to form a polymer precursor,where uniformly distributed organophosphonic ligand can induce a intense and homogeneously adsorption of VO₃^-by extensive coordination.The subsequent pyrolysis process not only ensures that V is uniformly dispersed on the support,but also achieves P in situ doping in the framework of g-C₃N₄.The introduction of organic phosphonic acid not only makes V/P-CN have a narrow band gap,porous nanosheet morphology,increased specific surface area,but also improves the dispersibility of V and gives it an electron-rich structure.The electron transfer rate from the P-doped g-C₃N₄ to V-based nanocomposites in V/P-CN is enhanced as compared with the pristine one without P doping（V/CN）.Radical scavenger experiment further suggests the significant electron interaction in the heterojunction catalysts increases the electron density near the V active species and the electron transfer acts as the rate-determining step of the ODS reaction,thus V/P-CN exhibits impressive catalytic ODS activity.2.Mesoporous titanium phosphonates（MTP）with sufficient organophosphonic ligands are employed as the support to load highly dispersed molybdenum oxides active component for the preparation of efficient ODS catalysts.The organophosphonic groups homogeneously anchored on the MTP allow monolayer adsorption of Mo₇O₂₄^6-by extensive coordination with the organic bridging groups,and subsequent low-temperature annealing achieve the high dispersion of molybdenum oxide active components on the surface of MTP with strong coupling effect.The electron-donating effect of organophosphonic ligands confers a high electron density on the Mo active site.In addition,the mesoporous structure and large specific surface area of MTP are conducive to the diffusion of oil and increase the concentration of reactants around the active site.Compared with the catalysts prepared by commercial P25 and inorganic titanium phosphate as supports,the ODS catalytic activity of Mo/MTP catalysts is significantly improved.3.Hollow spherical hybrid（CoPi-HSNPC）composed of cobalt phosphate and sufficient heteroatom-doped carbon was successfully prepared by direct pyrolysis of cobalt phosphonates following the metal phosphonate-derived strategy.The homogeneous distribution of organophosphonic ligands in cobalt phosphonate hybrid framework evidently ensure the intimately coupled interaction between the in-situ formed heteroatoms-doped conductive carbon substrates and cobalt phosphate nanoparticles.Due to the higher intrinsic activity of cobalt phosphate,the enhanced conductivity of heteroatoms-doped carbon and the hierarchical porous hollow spherical structure,the as-prepared CoPi-HSNPC show extraordinary electrocatalytic activity and stability toward OER under alkaline conditions.In addition,Ni-based and Mn-based hollow spherical hybrids were also synthesized by this simple metal phosphonate-derived strategy,and they both have good performance for OER process.