Au/CuO_x-TiO₂Catalysts for CO Oxidation at Low Temperature

A series of Au/CuOx-TiO2 with various Cu/Ti ratios were prepared. CuOx/TiO2 was prepared by incipient-wetness im- pregnation with aqueous solution of copper nitrate. Au catalysts were prepared by deposition-precipitation method at pH 7 and 338 K. The catalysts were characterized by inductively-coupled plasma-mass spectrometry, temperature pro- gramming reduction, X-ray diffraction, transmission electron microscopy, high-resolution transmission electron mi- croscopy and X-ray photoelectron spectroscopy. The reaction was carried out in a fixed bed reactor with a feed con- taining 1% CO in air at WHSV of 120,000 mL/h·g. High gold dispersion and narrow size distribution was obtained. The addition of CuOx in Au/TiO2 enhanced the activity on CO oxidation significantly. CuOx was in amorphous state which could stabilize the Au nanoparticles. Cu was in Cu1+ state. Cu donated partial electrons to Au. The interactions among Au, Cu1+ and TiO2 account for the high catalytic activity for CO oxidation. The significant promotional effect of CuOx on CO oxidation at low temperature was demonstrated.

Review of organic and inorganic pollutants removal by biochar and biochar-based composites

Biochar(BC)has exhibited a great potential to remove water contaminants due to its wide availability of raw materials,high surface area,developed pore structure,and low cost.However,the application of BC for water remediation has many limita-tions.Driven by the intense desire of overcoming unfavorable factors,a growing number of researchers have carried out to produce BC-based composite materials,which not only improved the physicochemical properties of BC,but also obtained a new composite material which combined the advantages of BC and other materials.This article reviewed previous researches on BC and BC-based composite materials,and discussed in terms of the preparation methods,the physicochemical properties,the performance of contaminant removal,and underlying adsorption mechanisms.Then the recent research progress in the removal of inorganic and organic contaminants by BC and BC-based materials was also systematically reviewed.Although BC-based composite materials have shown high performance in inorganic or organic pollutants removal,the potential risks(such as stability and biological toxicity)still need to be noticed and further study.At the end of this review,future prospects for the synthesis and application of BC and BC-based materials were proposed.This review will help the new researchers systematically understand the research progress of BC and BC-based composite materials in environmental remediation.

Quantum mechanics calculation of the Kubo effect for the face-centered cubic structure of nanometallic hydrogen

The total energy of the cubic_octahedral structure of H\++ cluster is calculated by means of the modified arrangernent channel quantum mechanics (MACQM). The present result shows that the face_centered cubic(FCC) structure ofnanometallic hydrogen manifests Kubo effect.