Construction Of Two-dimensional Hexagonal Boron Nitride For Catalytic Oxidation Desulfurization Of Diesel

Under the theme of"Peace and Development",clean energy and environmental protection have become priority issues in international politics.Although the development of new energy is rapid,it is undeniable that most new energies are still in the developing stage,and fossil fuel will still live in many fields for a long time.Therefore,the clean production of fossil fuel has become one of the focuses for the current environmental protection.Diesel is a kind of light petroleum products,and the sulfide in diesel will be converted into SO_x and released in combustion of diesel,which not only pollutes the atmosphere,but also seriously threatens the quality of peoples live.Therefore,the desulfurization of diesel is imperative.In view of the shortcomings of hydrodesulfurization technology widely employed in industry,a series of two-dimensional hexagonal boron nitride（h-BN）based catalysts were designed and synthesized for the removal of aromatic thiophene sulfide in diesel via catalytic oxidation desulfurization（ODS）.This research makes the catalytic ODS technology close to its future industrial application.The main conclusions of this research are as follows:1.A kind of carbon and oxygen Co doped boron nitride（BCNO）catalyst was prepared by calcining in ternary eutectic solvent（DES）.The structure entropy of BCNO catalyst was controlled by changing the type of quaternary ammonium salt composed of DES.The prepared BCNO catalyst was applied to activate O₂ for the catalytic oxidation of aromatic thiophene sulfide in model diesel.The relationship between the structure entropy of the catalyst and the free radical induction period of the catalytic oxidation reaction was investigated.The results showed that the high entropy structure of BCNO catalyst could promote the catalytic oxidation reaction.Under the optimal reaction conditions,the BCNO catalyst can activate O₂ at 125°C to realize the fast catalytic oxidation of dibenzothiophene（DBT）,4-methyldibenzothiophene（4-MDBT）and 4,6-dimethyldibenzothiophene（4,6-DMDBT）in model diesel.2.Cobalt porphyrin supported two-dimensional boron nitride（TCl PPCo/BN）catalysts were successfully prepared by immobilizing cobalt porphyrin on the two-dimensional plane of h-BN.The morphology and reaction sites of TCl PPCo/BN catalyst were characterized,and theπ-πinteraction between porphyrin cobalt and h-BN was revealed.In addition,the electronic structures of Co atoms in the center of cobalt porphyrin before and after immobilization were also compared.Using octanal as sacrificial agent,the prepared TCl PPCo/BN catalyst was applied to activate O₂ to catalyze the oxidation of aromatic thiophene sulfide in model diesel,and the catalytic reaction conditions were optimized.A rapid oxidation of DBT in model diesel was successfully realized at 50 C.The biomimetic catalytic mechanism of TCl PPCo/BN catalyst was revealed by modifying electron withdrawing and electron donating functional groups on cobalt porphyrin,respectively.3.Manganese porphyrin supported two-dimensional few-layered boron nitride（TPPMn BN）catalysts were synthesized by immobilizing manganese porphyrin on the two-dimensional plane of few-layered h-BN.The morphology and reaction sites of TPPMn BN catalyst were characterized,and the electron transfer effect between manganese porphyrin and h-BN support was studied.Using isobutyraldehyde as sacrificial agent,TPPMn BN catalyst was applied to activate O₂ for the catalytic oxidation of aromatic thiophene sulfide in model diesel.Under the optimal reaction conditions,the TPPMn BN catalyst can rapidly achieve the catalytic oxidation of DBT,4-MDBT and 4,6-DMDBT in model diesel at 30°C.The effect of electron transfer on the catalytic reaction sites of TPPMn BN catalyst was studied by electron spin resonance and reactive oxygen species elimination experiments,and the biomimetic catalytic mechanism of TPPMn BN catalyst was revealed.4.Zn-Por-Br/BN catalyst with high catalytic performance was successfully prepared by immobilizing ionic liquid fragment modified porphyrin zinc（Zn-Por-Br）onto a few-layered h-BN support.The morphology and reaction sites of the as prepared Zn-Por-Br/BN catalyst were characterized,and the electron transfer effect between Lewis acid and base sites in the molecular structure of Zn-Por-Br and h-BN support was studied.The results showed that Lewis acid sites and Lewis base sites could transfer electrons to the h-BN carrier independently,and finally enhanced their strength.The Zn-Por-Br/BN catalyst was applied to activate O₂ without any sacrificial agent for the catalytic oxidation of aromatic thiophene sulfide in model diesel.The catalytic reaction conditions were optimized and a rapid catalytic oxidation of DBT in model diesel was successfully realized at 110°C.In addition,the adsorption of DBT on the surface of Zn-Por-Br/BN catalyst was also studied,and a possible Lewis acid-base synergistic catalytic mechanism was proposed.5.A series of BNNT-WO_x catalysts containing Lewis acid-base sites were fabricated by in-situ growth of oxygen-defective tungsten oxide（WO_x）nanoparticles in boron nitride nanotubes（BNNTs）.The morphology and reaction sites of BNNT-WO_xcatalysts were characterized,and the effect of peroxytungstic acid ionic liquid on the morphologies of BNNTs and WO_x nanoparticles was studied.In addition,the electron transfer effect between WO_x nanoparticles and BNNTs in BNNT-WO_x catalyst was studied,and the formation of defect structure in BNNT-WO_x catalyst was revealed.The BNNT-WO_x catalyst was used to activate H₂O₂ for the catalytic oxidation of aromatic thiophene sulfide in model diesel.By optimizing the catalytic reaction conditions,BNNT-WO_x catalyst successfully achieved rapid catalytic oxidation of benzothiophenes and dibenzothiophenes in model diesel at 60°C.In addition,in the presence of aromatics,olefins and cycloalkanes,the selectivity of BNNT-WO_x catalyst for catalytic oxidation of sulfide was also studied.Based on the kinetic analysis of catalytic oxidation reaction and Lewis acid-base site elimination experiments,the contribution of adsorption process to the catalytic selectivity of BNNT-WO_x catalyst was revealed.