Microstructural Modulation Of TiO₂ Loading With RuO₂ For Catalytic Oxidation Of HCl

The catalytic oxidation of by-product HCl to Cl₂,the Deacon reaction,is one of the most economical,green and effective way to deal with the recycling of chlorine resources in the chlor-alkali industry.Ru-based catalysts possess excellent catalytic activity and stability due to their unique structures,which directly pushes the reaction process into industrialization.The active component RuO₂has similar lattice parameters with the rutile TiO₂support,and can be spread on the surface of the carrier to expose the corresponding crystalline surface.So far,the research in this field is mainly focused on the active component,while the influence of the crystalline surface of the carrier on the active component and its catalytic performance has not been deeply investigated.To this end,this thesis takes the carrier TiO₂as the research object and investigates the effect of different（110）crystalline facets on the performance of the catalytic oxidation of HCl by loading RuO₂on TiO₂,The main results of this thesis are as follows.1.The grain size of（110）-rich rutile phase TiO₂can be regulated by changing the concentrations of TiCl₄and hydrochloric acid.When the concentrations of TiCl₄and hydrochloric acid were 0.03 mol/L and 3.5 mol/L,respectively,the synthesized TiO₂-（110） was in the shape of long rods and uniformly dispersed,and its performance of the catalytic oxidation of HCl loaded with RuO₂was the best.2.The catalytic activity of RuO₂/TiO₂-（110）catalyst was significantly better than that of RuO₂/TiO₂-（NPs）（NPs:commercial TiO₂ nanoparticles）catalyst at 1.0 wt%and 0.5 wt%of RuO₂loading;moreover,RuO₂/TiO₂-（110）catalyst could largely improve RuO₂at dilute oxygen concentration HCl conversion,and the HCl conversion of 1.0 wt%RuO₂/TiO₂-（110）at a reaction stoichiometry ratio of 4:1 between HCl and O₂still reached 30%.Combined with various technical characterizations,RuO₂dispersion on（110）-rich crystalline TiO₂is better and easy to form thin films compared to nanoparticle TiO₂,thus improving the utilization of active components.3.To further investigate the effect of（110）crystalline plane ratio in TiO₂on its performance in the catalytic oxidation of HCl by RuO₂ loading,we regulated the ratio of（110）crystalline plane and（111）crystalline plane of TiO₂by controlling the ratio of the precursor TiCl₄to F^-.With the increase of F^-addition,the ratio of（110）crystalline plane of TiO₂gradually decreases,and the conversion rate of its loaded RuO₂-catalyzed HCl oxidation decreases.Combined with the characterization,the（110）crystalline surface of the carrier TiO₂facilitates the dispersion of the active component RuO₂,which increases the number of active sites on the catalyst surface and makes it easier for O₂to adsorb and dissociate,thus improving its catalytic activity and HCl conversion under dilute oxygen conditions.The innovation of this thesis is to study the effect of crystalline surface modulation of the TiO₂supported by RuO₂on its performance of catalytic oxidation of HCl.By preparing TiO₂with high（110）crystalline surface exposure ratio,RuO₂ can be highly dispersed on the carrier surface,which can increase the number of active sites and improve the activation efficiency of O₂molecules during the oxidation of HCl.The high activity and low loading Ru-based catalysts in this research can significantly reduce the industrial cost of HCl catalytic oxidation to Cl₂and provide scientific basis and technical support for the recycling of chlorine resources.