BET theory

About: BET theory is a research topic. Over the lifetime, 9046 publications have been published within this topic receiving 286142 citations.

Zeolite-templated carbon materials for high-pressure hydrogen storage.

Abstract: Zeolite-templated carbon (ZTC) materials were synthesized, characterized, and evaluated as potential hydrogen storage materials between 77 and 298 K up to 30 MPa. Successful synthesis of high template fidelity ZTCs was confirmed by X-ray diffraction and nitrogen adsorption at 77 K; BET surface areas up to ~3600 mT2 g^(–1) were achieved. Equilibrium hydrogen adsorption capacity in ZTCs is higher than all other materials studied, including superactivated carbon MSC-30. The ZTCs showed a maximum in Gibbs surface excess uptake of 28.6 mmol g–1 (5.5 wt %) at 77 K, with hydrogen uptake capacity at 300 K linearly proportional to BET surface area: 2.3 mmol g^(–1) (0.46 wt %) uptake per 1000 m^2 g^(–1) at 30 MPa. This is the same trend as for other carbonaceous materials, implying that the nature of high-pressure adsorption in ZTCs is not unique despite their narrow microporosity and significantly lower skeletal densities. Isoexcess enthalpies of adsorption are calculated between 77 and 298 K and found to be 6.5–6.6 kJ mol^(–1) in the Henry’s law limit.

Textural characteristics of activated carbon by single step CO2 activation from coconut shells

Abstract: The use of coconut shells as feedstock for the preparation of activated carbons is well adopted industrially, using conventionally two stage activation process, either using steam or CO 2 as the activating agent. The present study attempts to utilize a one-step CO 2 activation to prepare activated carbon from coconut shell, which has received far less scientific attention. Experimental results show that activation temperature, CO 2 flow-rate, holding time and heating rates have significant effects on BET surface area, micropore volume and pore size distribution (PSD). The optimum conditions for activation have been found to be an activation temperature of 900 °C, a CO 2 flow-rate of 200 cm 3 /min, a holding time of 140 min, and a heating rate of 10 °C/min. The optimum conditions yielded an activated carbon with a BET surface areas of 1667 m 2 /g and micropore volume of 0.8949 cm 3 /g, which are significantly higher than the activated carbon produced either using two stage activation process or one-step steam/CO 2 activation for other precursors.

Novel sulfation effect on low-temperature activity enhancement of CeO2-added Sb-V2O5/TiO2 catalyst for NH3-SCR

Abstract: Sulfur dioxide (SO2) is considered as a poisoning gas for NH3-SCR catalysts under real time conditions. However, it has revealed an obvious beneficial effect on the activity of CeO2 containing catalysts. Hereby we report the applied research in sulfation effect on low-temperature activity enhancement of CeO2-modified, Sb2O3–V2O5–TiO2 catalyst system pretreated with SO2 under oxidizing conditions at different temperatures for 2 h. We have elucidated the real insights via nature-property relationships of the species formed at various SO2 pretreatment temperatures (T = 300, 400 and 500 °C) with the help of advanced characterization techniques such as X-ray diffraction (XRD), temperature programmed reaction (NH3-TPD, NO-TPD and H2-TPR), BET surface area, scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM–EDS) and X-ray photoelectron spectroscopy (XPS). Our results indicated that SO2 pre-treatment at 500 °C led to the maximum favorable sulfation with cerium(III) sulfate as the major surface species.