The Design,Preparation,and Properties Of Zr Based(Composite) Metal Oxide Nanomaterial Catalysts

Nowadays,urged by the decreasing fossil resources and growing environmental concerns,tremendous efforts have been devoted to exploiting economically efficient and environmental friendly technologies to use biomass as feedstock for the production of bio-based platform molecules and convert these molecules into desired value-added chemicals.In the process of catalytic transformation of biomass,the removal of functional groups,especially oxygen-containing functional groups,put forward a higher requirement for the specificity of catalysts.As the catalyst used in the transformation of biomass suffering from the poor stability,low recycling utilization and low selectivity,it is more significative to explore the connection between catalyst structure and its catalytic performance and optimize the preparation condition of catalyst for reaching high catalytic performance.As one of the most widely used catalyst supports,Zr02 has a high surface area for the dispersion of metal nanoparticles,a porous structure for transferring reactants and products,a large amount of surface Zr4+-O2-acid-base centers and oxygen vacancies for tailoring the catalytic performance and stabilizing the metal particles from aggregation through the metal-support interaction.In this paper,we developed a novel method for the preparation of supported metal catalysts and acid-base bifunctional catalysts and used for the catalytic transformation of GVL and furfural,respectively.And the fundamental reason for the high activity and high selectivity of the catalyst was studied:(1)A novel separate nucleation and aging steps assistant reduction-oxidation strategy was developed for the synthesis of Cu/Zr02 catalysts.It was found that the surface Cu+/(Cu0 + Cu+)molar ratio of Cu/ZrO2 catalyst can be simply manipulated by varying the initial NaBH4 concentration.The catalysts process remarkable stability and efficiency in the catalytic transformation of GVL to pentyl valerate,which may attribute to the cooperation between Cu+and Cu0 originating from enhanced metal-support interaction and highly dispersed CuO nanopareticles of the CuO/ZrO2 precursors.The correlation between the catalytic performance and the surface Cu active components demonstrates that Cu+ is the active site for the adsorption and polarization of GVL,while Cu0 undertakes the hydrogenation of intermediates.The present study could inspire the development of readily available,stable,highly efficient metal catalysts with superior performance in the flexible conversion of bio-derived platform molecules in terms of economic and environmental sustainability.(2)A novel separate nucleation and aging steps assistant dynamic hydrothermal crystallization strategy was developed for the synthesis of Al/Zr complex catalysts.It was found that the texture feature of Al/Zr catalysts and the content and distribution of acid-base active centers can be simply manipulated by varying the capacity of Al.The catalysts process remarkable stability and efficiency in the catalytic transformation of furfural to furfurylidene-acetone,which may attribute to the synergy between acid and base active centers on the surface of Al/Zr catalysts.The prepared Al/Zr catalyst has the same advantage in the aldol condensation reaction of other typical aldehydes and ketones.