Solid-state Synthesis Of High Efficient Nanocatalysts And Their Applications

Transition metal oxide and metal nanocatalysts have been widely used in the field of environment and energy due to their special physico-chemical properties and excellent catalytic performances.Unfortunately,the current preparation methods of nanocatalysts are inevitable to involve complex processes or expensive raw materials.Futhennore,the catalytic activity and stability are usually not satisfied.In this thesis,we report a simple solid-state route to synthesis of high-quality Co3O4 and NixCu1-x@C nanocatalysts using a single organic-inorganic layered hydroxides precursor and realize their large-scale,controllable synthesis.The detail contents are listed as follows:1.One dimensional mesoporous Co3O4 nanocatalyst with oxygen vacancies and high crystallinity could be easily prepared in large quality by a direct calcination of an organic-inorganic layered hydroxide precursor at a low temperature.When used the as-prepared Co3O4 for the degradation of toxic organic dye Orange ?,it exhibited 5 times better catalytic activity than commercial Co3O4.What's more,it remained really high degradation efficiency after 5 times recycles.When used Co3O4 as electrocatalyst for OER,the overpotential and stability of was much higher than commercial 20%Pt/C nanocatalyst.The excellent catalytic performance was mainly attribute to the existense of oxygen vacancies could more favorably adsorb and interact with OH-species,forming Co-O bonding,thus promoting the electron transfer.2.High-quality NixCu1-x@C nanocatalysts could be easily prepared by a direct calcination of an organic-inorganic layered hydroxide precursor without the addition of extra carbon sources and reducing agents.By tuning the reaction conditions,the controllable synthesis of the nanocatalyts was succeeded.The characterization results demonstrate that:(?)NiCu alloy nanoparticles(?10 nm)uniformly distributed in the graphitic carbon matrix,avoiding the aggragation and oxidation of the NiCu nanoparticles;(?)organic molecules in-situ translated into porous graphitic carbon with plenty of hydroxyl groups;(?)the NiCu-O-C bond formed with strong interaction between NiCu and C;(?)mesoporous NiCu@C nanoccatalysts exhibited large surface area(128.18 m2/g).Ni0.75Cu0.25@C obtained at 500? exhibited the best performance(superior to commercial 20%Pt/C)for the reduction of p-nitrophenol by NaBH4.Because of the introduction of nickel element,NiCu@C nanocatalysts can be separated easily by a magnet for recycling.NixCu1-xx@C nanocatalysts also exhibited good performance as electrocatalysts for methanol oxidation.In conclusion,we have developed a simple solid-state approach for the synthesis of high-quality Co3O4 and NixCu1-x@C nanocatalysts with excellent catalytic performances.Considering the simple preparation routes,environmental friendly and easy to large-scale synthesis,this solid-state method could be extended to a wide range of other transition metal oxides,metals,alloys and carbon materials for wide applications,suggesting the potential applications to modern chemical industry.