A biomorphic CeO2microtube with multiple-pore structure was fabricated by using the cotton as biotemplate,throughcerium nitrate solution infiltration and thermal decomposition.Field emission scanning electron microscope(FESEM),powder X-raydiffraction(XRD),transmission electron microscope(TEM),N2adsorption?desorption isotherms,temperature-programmedreduction(TPR)and CO oxidation were used to characterize the samples.The results indicated that the synthesized products werecomposed of crystallites with grain size about9nm and exhibited a fibrous morphology similar to the original template andpossessed a specific surface area(BET)of62.3m2/g.Compared with the conventional CeO2particles,the synthesized materialsshowed a superior catalytic activity for CO oxidation.For the synthesized fibrous CeO2,the CO conversion at320°C was above90%and a100%CO conversion was obtained at410°C.
A hierarchical micro-nano porous carbon material (MNC) was prepared using expanded graphite (EG), sucrose, and phosphoric acid as raw materials, followed by sucrose-phosphoric acid solution impregnation, solidification, carbonization and activation. Nitrogen adsorption and mercury porosimetry show that mixed nanopores and micropores coexist in MNC with a high specific surface area of 1978 m2·g-1 and a total pore volume of 0.99 cm3·g-1. In addition, the MNC is found to consist of EG and activated carbon with the latter deposited on the interior and the exterior surfaces of the EG pores. The thickness of the activated carbon layer is calculated to be about one hundred nanometers and is further confirmed by scanning electron microscope (SEM) and transmission election microscope (TEM). A maximum static phenol adsorption of 241.2 mg·g-1 was obtained by using MNC, slightly higher than that of 220.4 mg·g-1 by using commercial activated carbon (CAC). The phenol adsorption kinetics were investigated and the data fitted well to a pseudo-second-order model. Also, an intra-particle diffusion mechanism was proposed. Furthermore, it is found that the dynamic adsorption capacity of MNC is nearly three times that of CAC. The results suggest that the MNC is a more efficient adsorbent than CAC for the removal of phenol from aqueous solution.
Liu ChengbaoChen ZhigangNi ChaoyingChen FengGu ChengCao YuWu ZhengyingLi Ping
