Papers by Author: Jin Zhou

Abstract: Ordered mesoporous carbons (BOMC) were prepared by doping boric acid using a hard-templating method, while a CMK-3 carbon (OMC) was also prepared for comparison. The capacitive performance of these two carbons was investigated in ionic liquid of EMImBF₄ and EMImTSFI. As demonstrated by the structure analysis, BOMC possesses almost same surface area and pore size as OMC, while the former carbon possesses higher content of oxygen-containing groups. In ionic liquid electrolyte, the carbons mainly show typical electric double layer capacitance, and the capacitance retention ratio and ion diffusion of electrolyte is determined to the surface chemical property. BOMC present visible pseudo-capacitance due to the oxygenated groups in hydrophilic EMImBF₄, while no visible pseudo-capacitive behavior was observed in hydrophobic EMImTSFI.

Abstract: Several microporous carbons were prepared by a two-step method using zeolite HY as a template, and were used as CO₂ adsorbents. X-ray diffraction patterns present that the structure regularity of the zeolite has been well-replicated by the templated carbons. X-ray photoelectron spectroscopy confirms that the prepared carbons possess abundant nitrogen-containing groups due to the carbon deposition of acetonitrile. The prepared carbons show high CO₂ adsorption capacity due to its very high microporous surface area and abundant basic nitrogen-containing groups.

Abstract: Arrays of ordered carbon nanotubes (OCNT) was synthesized successfully using aluminated mesoporous silica as hard template. XRD tests and TEM observations showed that OCNT was composed of carbon nanotube arrays in p6mm symmetry. N₂ sorption analyses demonstrated that OCNT possesses typical mesoporous structure and centralized mesopore distribution. OCNT are superior to Maxsorb, an active carbon with super high surface area, in capacitive behavior and power output due to their ordered pore-structure, which favors the fast diffusion of hydrated ions. As evidenced by cyclic voltammetry measurements, OCNT show good capacitive behaviors (exhibiting a high capacitance of 180 F/g even at very high sweep rate of 50 mV/s, as compared with much reduced capacitance of 73 F/g for Maxsorb at the same sweep rate). OCNT can provide very high power density while still maintaining good energy density, thus having potential uses in electrochemical double layer capacitor (EDLC), particularly where both high power output and energy density are required.

Abstract: Nanoporous carbons were prepared from rice husk (RH) according to a three-step procedure that includes pre-carbonization, silica removal and chemical activation. The surface area and pore structure of the nanoporous carbons are characterized intensively using N₂ adsorption technique. The as-prepared carbons have specific surface area of up to 3283 m²/g, and total pore volume of up to 1.8 cm³/g. The effect of activating agent dosage on the pore structure of carbons was investigated and elucidated clearly. As evidenced by electrochemical measurements, the as-prepared carbons have good capacitive performances and their specific capacitances are much higher than ordered mesoporous carbon, thus highlighting the success of preparing high performance electrode material for EDLC from a biomass waste, rice husk.