New Routes For Construction Of Strong Metal-support Interactions And Preparation Of Highly Efficient Heterogeneous Catalysts

Strong metal-support interactions can not only effectively adjust the charge state and structure,but also enhance the sinter-resistant of the catalysts.Futhermore,the catalytic activity and selectivity of the catalysts can also be regulated by forming abundant interfacial sites.The construction of classical strong metal-support interaction(SMSI)involves in redox treatments at high-temperatures,sometimes causing sintered metal nanoparticles before SMSI formation.In addition,it is shown the construction of SMSI between metal nanoparticles and inert oxide supports is relatively difficult compared with that of metal nanoparticles on reduciable oxide supports,which directly limits the applications of SMSI.In order to provide an alternative strategy to these issues,a wet-chemistry methodology was proposed to construct SMSI at room temperature to avoid sintering of the metal nanoparticles before the formation of SMSI.In addition,we address that the SMSI can be realized on inert oxide supported Au nanoparticles through Le Chatelier’s principle.Furthermore,it is also shown that the strong interactions between single-site metal species and oxide support can effectively boosts the oxidative cyanation of alcohols.Furthermore,the Mn-Ce catalyst with excellent performance for the oxidative dehydrogenation of propane was prepared by constructing strong oxide-support interaction(SOSI).The main results are as follows:1.The wet-chemistry strong metal-support interaction(wcSMSI)was successfully constructed on titania-supported Au nanoparticles in aqueous solution at room temperature.Key to the success is the construction of redox interactions between Ti3+cations and oxidized gold nanoclusters(Auδ+)surface.Owing to the wcSMSI,the Au-TiOx interface with an improved redox property is favorable for oxygen activation,thus accelerating CO oxidation.More importantly,the catalyst with wcSMSI shows excellent stability in the long-term stability test because oxide overlayers efficiently stabilize the Au nanoparticles.2.The SMSI between irreducible oxides(e.g.,MgO)and noble metal nanoparticles(e.g.,Au)was successfully constructed by CO2 treatment at appopriate temperature following the Le Chatelier’s principle.The resulted catalyst exhibited electronic and geometric features that are similar to those of the classical SMSI.The key to achieve this success is to activate the oxide surface through a reversible reaction(e.g.,MgO+CO2(?)MgCO3),that is,CO2 interacts with MgO surface to form carbonate species at low temperature and then decomposed in CO2 atmosphere at high temperature due to the Le Chatelier’s principle,resulting in the support migration onto Au nanoparticles to form encapsulation.The encapsulation is permeable to the reactant molecules,stable under the oxidation conditions,and even water-tolerant to outperform the classical SMSI,resulting in sinter-resistant Au nanoparticle catalysts under harsh conditions and long-term CO oxidation reaction.3.The strong interactions between single-site ruthenium(Ru)species and manganese oxide(MnO2)nanorods results in the catalyst with excellent performance and stability in ammoxidation of alcohols.The single-site Ru species enhance the ammonia resistance of the catalyst,and the strong interactions between Ru and MnO2 support lead to the formation of abundant interfacial sites(Ru-O-Mn),which accelerate the catalyst performance in alcohol dehydrogenation and oxygen activation.As a result,the catalyst is highly active,selective,and stable for ammoxidation of various alcohols to give corresponding nitriles(34 kinds)with molecular oxygen and ammonia as the reactants.4.The amorphous manganese oxide(MnOx)with thin-layer morphology was anchored on a ceria support(CeO2)via construction of strong oxide-support interaction(SOSI),which effectively regulated the chemical properties of oxygen species on the catalyst surface,and successfully transformed the MnOx-CeO2 from a combustion catalyst into a selective catalyst for oxidative dehydrogenation of propane.Multiple investigations demonstrate that the SOSI forms active interfacial oxygen sites for propane activation and oxygen-deficient manganese oxide to stabilize propene and hinder overoxidation under the ODHP conditions,outperforming the general manganese oxide catalysts and even the practically promising vanadium catalysts.