Topic
BET theory
About: BET theory is a research topic. Over the lifetime, 9046 publications have been published within this topic receiving 286142 citations.
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TL;DR: The study highlights the ability to control free-standing nanoporous gold monoliths with high surface area, and well-defined, tunable pore morphology.
Abstract: Nitrogen adsorption/desorption isotherms are used to investigate the Brunauer, Emmett, and Teller (BET) surface area and Barrett-Joyner-Halenda (BJH) pore size distribution of physically modified, thermally annealed, and octadecanethiol functionalized np-Au monoliths. We present the full adsorption-desorption isotherms for N2 gas on np-Au, and observe type IV isotherms and type H1 hysteresis loops. The evolution of the np-Au under various thermal annealing treatments was examined using scanning electron microscopy (SEM). The images of both the exterior and interior of the thermally annealed np-Au show that the porosity of all free standing np-Au structures decreases as the heat treatment temperature increases. The modification of the np-Au surface with a self-assembled monolayer (SAM) of C18-SH (coverage of 2.94 × 1014 molecules cm−2 based from the decomposition of the C18-SH using thermogravimetric analysis (TGA)), was found to reduce the strength of the interaction of nitrogen gas with the np-Au surface, as reflected by a decrease in the ‘C’ parameter of the BET equation. From cyclic voltammetry studies, we found that the surface area of the np-Au monoliths annealed at elevated temperatures followed the same trend with annealing temperature as found in the BET surface area study and SEM morphology characterization. The study highlights the ability to control free-standing nanoporous gold monoliths with high surface area, and well-defined, tunable pore morphology.
224 citations
TL;DR: In this paper, X-ray diffraction, BET surface area analysis, UV-vis diffuse reflectance spectroscopy, transmission electron microscopy, and Xray photoelectron spectroscopic analysis were performed on Nanocrystalline Bi2MoO6 photocatalysts.
223 citations
TL;DR: Low impregnation ratio and activation temperature are favorable to the formation of acidic surface functional groups, which consist of temperature-sensitive and temperature-insensitive two parts, which are stable even at 500 degrees C.
223 citations
TL;DR: The advertisersorption of TC on Zn-BC agreed well with the pseudo-second-order model and the Langmuir isotherm, and the thermodynamic parameters indicated that the adsorption process was a spontaneously endothermic reaction.
220 citations
TL;DR: In this article, a mesoporous MCM-41 molecular sieve supported on porous materials, including NaY and Na-mordenite zeolites, was used for photodegradation of aromatic pollutants in water.
Abstract: TiO2 was supported on porous materials, including NaY and Na-mordenite zeolites, as well as mesoporous MCM-41 molecular sieve by using impregnation method with organic solvents. The products were characterized with powder XRD, BET surface area measurement, TEM, IR, Raman and UV–VIS spectroscopies. The supported TiO2 was crystallized in anatase structure and the intensity of its X-ray diffraction peaks increased with TiO2 loading. In contrast, the total surface area of the supported catalyst decreased with TiO2 loading. A blue shift of the absorption edge in the UV–VIS spectra was observed when TiO2 particle size decreased, a phenomenon corresponding to the particle size quantization effect. For photodegradation of aromatic pollutants in water, the activity was found strongly influenced by the chemical nature of the pollutant and the surface property of the support. For volatile pollutants such as benzene and chlorobenzenes, molecular sieve supports facilitated the photodegradation reaction by providing high surface area for adsorption. Moreover, there is an optimal loading of TiO2 to achieve the best photocatalytic activity on various supports. The supports in contrast did not show positive contribution in degradation of hydrophilic pollutants such as phenol.
220 citations