Synthesis, Characterization And Performance Of Nickel Oxide Matrix Composites

Composite materials have many unique properties and have been applied in electrochemical, magnetic materials, industrial catalysis and many other fields. Composite materials with different structures have formed an inorganic material family. Among them, nickel oxide matrix composites play a key role in the field of electrochemical supercapacitor and have potential applications in environmental catalysis as promising functional inorganic materials. The properties of nickel oxide matrix composites are closely related to changes in morphology and composition. The relationship between preparation methods and structures of nickel oxide matrix composites is in-depth explored by scientists. The interaction among the various components of nickel oxide matrix composite material leads to different performance, which is also a hot topic. In this paper, series of porous Co-Ni bimetal oxides with various compositions have been prepared in alcohol-oleylamine system. We fully investigate the influence of Co content in the Ni-Co bimetal oxide catalysts on their physicochemical properties, such as the catalytic activity, the morphology, the textural structure and the surface state. A brief explanation is proposed to understand the reaction by considering the Ni-Co bimetal oxides catalysts as three different types. These results can be supportive for developing bimetal oxides catalysts.By increasing Co content in the reaction system, the as-prepared Ni-Co bimetal oxides system can be classified into three different crystal structure types. When Co percentage is less than20%, the samples adopt identical cubic crystal structure with pure NiO, which possesses higher surface area and better catalytic performance than others. As Co percentage in the system is between40%and60%, the samples tend to form a stable lamellar structure of NiCo2O4. Co3O4based crystal structure type of Ni-Co bimetal oxides is observed when Co percentage is more than80%. And NiO type samples show larger surface area, crystalline degree and better catalytic activity than NiCo2O4and Co3O4type samples. The samples are fully characterized by XRD, SEM/TEM, N2adsorption/desorption, H2-TPR analysis and the synergistic catalysis effect between Ni and Co is the key factor to the catalytic capacity of Ni-Co bimetal oxides for CO oxidation.On the base of the research above, it is clear that NiO typed samples can be used as an ideal support. So different shape-controlled Pd nanocrystals are doped on NiO nanosheets, which are shown to be different active and selective formation of acetophenone because of size and shape effect. Experiment results have shown that the facets on the surface of Pd nanocrystals have a strong influence on catalytic properties. Pd hexagonal/triangular plates are over50nm and the catalytic capacity has declined seriously. And when the size of Pd nanoparticles is below10nm,(100) facets has better catalytic ability than (111) facets.