This paper investigates the properties of TiO2‐based photocatalysts synthesised under supercriticalconditions.Specifically,the characteristics of Pt dispersed on TiO2catalysts obtained in supercriticalCO2are discusse...This paper investigates the properties of TiO2‐based photocatalysts synthesised under supercriticalconditions.Specifically,the characteristics of Pt dispersed on TiO2catalysts obtained in supercriticalCO2are discussed and compared with those of commercial TiO2.The photocatalytic activity of thesynthesised catalysts in the CO2photoreduction reaction to produce solar fuel is tested.The mainconclusion of the study is that photocatalysts with better or similar features,including high surfacearea,crystallisation degree,hydroxyl surface concentration,pore volume,absorbance in the visiblerange and methane production rate,to those of commercial TiO2may be produced for the reductionof CO2to fuel by synthesis in supercritical media.展开更多
Bismuth-doped tin dioxide （BTO） nanometer powders were prepared by the wet chemical method using tin tetrachloride （SnCl4）, bismuth nitrate [Bi（NO3） 3 ] and ammonia as raw materials. Non-bridge hydroxides and ca...Bismuth-doped tin dioxide （BTO） nanometer powders were prepared by the wet chemical method using tin tetrachloride （SnCl4）, bismuth nitrate [Bi（NO3） 3 ] and ammonia as raw materials. Non-bridge hydroxides and capillary force between particles were found to be key factors causing hard aggregation of BTO through analyzing the formation mechanism of hard aggregation. The hard aggregation of BTO was eliminated effectively when the Bi-Sn precursor （BSP） was treated with post processing including dispersing with ultrasonic wave, refluxing and distilling with addition of n-butanol and benzene （DRD） and drying by microwave. Characterized with X-ray diffraction （XRD） and transmission electron microscopy （TEM）, BTO spherical particles with tetragonal phase structure are well crystallized, dispersed easily and the average size was less than 10 nm.展开更多
The knowledge of two-phase cloud dispersion mechanism from HLG(hazardous liquefied gas) release is the prerequisite for accurate assessment and precise rescue of such accidents. In this paper, an experiment of two-pha...The knowledge of two-phase cloud dispersion mechanism from HLG(hazardous liquefied gas) release is the prerequisite for accurate assessment and precise rescue of such accidents. In this paper, an experiment of two-phase cloud dispersion from liquefied CO_(2) hole release is performed. The source terms, such as vapour mass fraction, release velocity and mean droplet diameter, are calculated based on thermodynamic theory. Taking phase transition of CO_(2) droplets to gas into account, CFD(computational fluid dynamics) model for two-phase cloud dispersion is established. The predicted cloud temperatures at the downstream agree well with the experimental data, with the maximum relative error of 5.8% and average relative error of 2.3%. The consequence distances in the downstream direction and in the crosswise direction calculated through two-phase model are larger than those through single-phase model,with the relative differences of 57.8% and 53.6% respectively. CO_(2) concentration calculated by twophase model is smaller in the vicinity of release hole, and larger beyond 0.135 m downstream. A smaller leakage rate results in a lower CO_(2) concentration and a higher cloud temperature.展开更多
We propose an experimental spectroscopy method for investigating the electrical characteristics of concentrated nanopowder dispersed systems based on compacted ZrO2. The technique is based on measurement of electroche...We propose an experimental spectroscopy method for investigating the electrical characteristics of concentrated nanopowder dispersed systems based on compacted ZrO2. The technique is based on measurement of electrochemical impedance of the compacts. A possibility is shown for using the technique to study the processes of structure formation in nanopowder dispersed systems. It is shown that the technique is quite sensitive to detect subtle effects due to the chemical composition of the reactants from which the dispersed phase has been synthesized and external electromagnetic fields. In particular, it has been determined that the powders produced by chemical deposition possess conductiv-ity by nanoparticle volume which is several order of magnitude lower than that for powders obtained from the chloride feedstock. It has been revealed that exposure to weak (H = 105 A/m - 106 A/m) pulsed magnetic fields leads to a redistribution of free charge carriers between volume and surface of the nanoparticles.展开更多
基金supported by Spanish Government (Project CTM 2011-26564)Regional Government of Castilla-La Mancha (Project PEII10-0310-5840)Iberdrola Foundation (Research Grant in Energy and the Environment 2010/12 for Susana Tostón)~~
文摘This paper investigates the properties of TiO2‐based photocatalysts synthesised under supercriticalconditions.Specifically,the characteristics of Pt dispersed on TiO2catalysts obtained in supercriticalCO2are discussed and compared with those of commercial TiO2.The photocatalytic activity of thesynthesised catalysts in the CO2photoreduction reaction to produce solar fuel is tested.The mainconclusion of the study is that photocatalysts with better or similar features,including high surfacearea,crystallisation degree,hydroxyl surface concentration,pore volume,absorbance in the visiblerange and methane production rate,to those of commercial TiO2may be produced for the reductionof CO2to fuel by synthesis in supercritical media.
文摘Bismuth-doped tin dioxide （BTO） nanometer powders were prepared by the wet chemical method using tin tetrachloride （SnCl4）, bismuth nitrate [Bi（NO3） 3 ] and ammonia as raw materials. Non-bridge hydroxides and capillary force between particles were found to be key factors causing hard aggregation of BTO through analyzing the formation mechanism of hard aggregation. The hard aggregation of BTO was eliminated effectively when the Bi-Sn precursor （BSP） was treated with post processing including dispersing with ultrasonic wave, refluxing and distilling with addition of n-butanol and benzene （DRD） and drying by microwave. Characterized with X-ray diffraction （XRD） and transmission electron microscopy （TEM）, BTO spherical particles with tetragonal phase structure are well crystallized, dispersed easily and the average size was less than 10 nm.
基金supported by the Natural Science Foundation of Shandong Province (ZR2021QB144)。
文摘The knowledge of two-phase cloud dispersion mechanism from HLG(hazardous liquefied gas) release is the prerequisite for accurate assessment and precise rescue of such accidents. In this paper, an experiment of two-phase cloud dispersion from liquefied CO_(2) hole release is performed. The source terms, such as vapour mass fraction, release velocity and mean droplet diameter, are calculated based on thermodynamic theory. Taking phase transition of CO_(2) droplets to gas into account, CFD(computational fluid dynamics) model for two-phase cloud dispersion is established. The predicted cloud temperatures at the downstream agree well with the experimental data, with the maximum relative error of 5.8% and average relative error of 2.3%. The consequence distances in the downstream direction and in the crosswise direction calculated through two-phase model are larger than those through single-phase model,with the relative differences of 57.8% and 53.6% respectively. CO_(2) concentration calculated by twophase model is smaller in the vicinity of release hole, and larger beyond 0.135 m downstream. A smaller leakage rate results in a lower CO_(2) concentration and a higher cloud temperature.
文摘We propose an experimental spectroscopy method for investigating the electrical characteristics of concentrated nanopowder dispersed systems based on compacted ZrO2. The technique is based on measurement of electrochemical impedance of the compacts. A possibility is shown for using the technique to study the processes of structure formation in nanopowder dispersed systems. It is shown that the technique is quite sensitive to detect subtle effects due to the chemical composition of the reactants from which the dispersed phase has been synthesized and external electromagnetic fields. In particular, it has been determined that the powders produced by chemical deposition possess conductiv-ity by nanoparticle volume which is several order of magnitude lower than that for powders obtained from the chloride feedstock. It has been revealed that exposure to weak (H = 105 A/m - 106 A/m) pulsed magnetic fields leads to a redistribution of free charge carriers between volume and surface of the nanoparticles.
