Shixiong Wang

Morphology-controlled synthesis of SnO2/C hollow core–shell nanoparticle aggregates with improved lithium storage

An effective approach of template-free alcoholysis is employed to prepare hollow core–shell SnO2/C nanoparticle aggregates as anode materials for Li-ion batteries. Amorphous carbon can be loaded on the SnO2 nanoparticles uniformly in the solvothermal alcoholysis process, and the subsequent calcination results in the formation of hollow core–shell SnO2/C nanoparticle aggregates. They exhibit a stable reversible capacity of 640 mA h g−1 at a constant current density of 50 mA g−1, and the capacity retention is maintained over 90.9% after 100 cycles. The intrinsic hollow core–shell nature as well as high porosity of the unique nanostructures ensures the electrode has a high capacity and a good electronic conductivity. The hollow loose structure offers sufficient void space, which sufficiently alleviates the mechanical stress caused by volume change. Herein, the SnO2/C electrode presents excellent electrochemical performance. This method is simple, low cost, mass-productive, and can also be used to prepare other advanced functional materials.

Morphology-controlled synthesis of cage-bell Pd@CeO2 structured nanoparticle aggregates as catalysts for the low-temperature oxidation of CO

A facile generic strategy of combining template assisted and solvothermal alcoholysis is employed to prepare cage-bell Pd@CeO2 nanoparticle aggregates as catalysts for the low-temperature oxidation of CO. The synthetic parameters are regulated to control the size of the as-prepared CeO2 mesospheres. The activities of Pd@CeO2 catalysts are higher than that of Pd supported on Al2O3, and the activity of 1 wt% Pd@CeO2 can be further improved and its T90 is 2 °C. The intrinsic cage-bell nature as well as high porosity of the unique nanostructures of the CeO2 support contributes greatly to the formation of large numbers of surface oxygen vacancies on Pd@CeO2 catalysts, and thus it exhibits superior catalytic activity. This method is simple, low cost, mass-productive, and can also be used to prepare other advanced functional materials.

Arsenic pollution and its treatment in Yangzonghai lake in China: In situ remediation

In this study, the effect of direct atomization and spraying a ferric chloride (FeCl3) solution to decrease the arsenic concentration and its pollution in Yangzonghai Lake, China, was investigated. Ten ships were used for spraying 6-8t of FeCl3 in the lake every day since October 2009. After spraying, the average concentration of arsenic in Yangzonghai Lake, which has an area of 31 km(2), an average depth of 20 m, and a water storage capacity of 604 million m(3), started to decrease from 0.117 mg L(-1). On 20 September 2010, the lowest arsenic level of 0.021 mg L(-1) was attained, with an arsenic removal rate as high as 82.0%. However, the source of pollution was not eliminated, and local rainfall mainly occurred in September; hence, arsenic concentration from October to December increased to 0.078 mg L(-1). At the beginning of 2011, the As concentration decreased and remained at 0.025-0.028 mg L(-1) from May to September. During the 2 years of FeCl3 treatment, the water quality improved from V Class to II-III Class of the Chinese standards, which remained consistent for 12 months. The total cost for this in situ water treatment was 29 million RMB, which was less than a hundredth of the expected expenditure of 4-7 billion RMB. The treatment method achieved goals such as high arsenic removal rate, easy operation, low cost, and ecological security. In this study, the changing patterns of the concentration of arsenic in Yangzonghai Lake from June 2008 to December 2014 were analyzed, and the following problems were discussed: the stability of iron-arsenic precipitates in the lake, the concentrations of ferric and chloride ions in the lake, the pH of the lake during treatment, the stability of iron-arsenic precipitates in the lakebed sediments, and the variation of phytoplankton species in the lake.

Phenol Removal from Aqueous System by Bis(2-ethylhexyl) Sulfoxide Extraction

Solvent extraction is generally considered as one of the important and effective techniques to remove toxic phenol from wastewater. This paper explores the solvent extraction of phenol from wastewater using bis(2-ethylhexyl) sulfoxide (BESO) as extractant. Various parameters such as equilibrium time, the volume percentage of BESO, pH value, and ionic strength of the aqueous solution on the phenol extraction were investigated. The results indicated that BESO exhibited excellent performance of phenol extraction. The extraction percentage increased from 97.26% to 99.47%, varying the BESO concentration from 10% (v/v) to 30% (v/v). The extraction percentage decreased with increasing temperature in the range of 298-343 K. FTIR spectra of fresh and phenol loaded BESO organic phase indicated the existence of the hydrogen bonding interactions between S=O groups and phenol molecules. The relationship between log D and log [BESO] suggested the stoichiometry of the extracted species was a 1:1 complex, namely, [PhOH]·[BESO]. Phenol stripping from the loaded organic phase by sodium hydroxide was feasible, and more than 99% of phenol could be stripped when the NaOH concentration was 0.5 mol L−1. The results obtained established that BESO/kerosene extraction system has potential for practical application in the phenol removal and recovery.

Hollow Nanotubular SnO2 Templated by Cellulose Fibers for Lithium Ion Batteries: Hollow Nanotubular SnO2 Templated by Cellulose Fibers for Lithium Ion Batteries

以植物纤维素(滤纸)为模板, 制备了中空SnO 2 纳米管作为锂离子电池负极材料。通过XRD、SEM、TEM和HR?TEM表征产物的组分、形貌和结构, 表明合成材料是由粒度大小为5~15 nm SnO 2 粒子组装成的中空纳米管。同时, N 2 吸附/脱附测试表明此材料为疏松的介孔结构。材料在电流密度100 mA/g 时, 可逆容量稳定在580 mAh/g, 60次循环后容量仍保持为550 mAh/g。制备的中空SnO 2 纳米管作为锂离子电池负极材料, 具有较高的放电容量和良好的电化学循环性能。以植物纤维素(滤纸)为模板, 制备了中空SnO 2 纳米管作为锂离子电池负极材料。通过XRD、SEM、TEM和HR?TEM表征产物的组分、形貌和结构, 表明合成材料是由粒度大小为5~15 nm SnO 2 粒子组装成的中空纳米管。同时, N 2 吸附/脱附测试表明此材料为疏松的介孔结构。材料在电流密度100 mA/g 时, 可逆容量稳定在580 mAh/g, 60次循环后容量仍保持为550 mAh/g。制备的中空SnO 2 纳米管作为锂离子电池负极材料, 具有较高的放电容量和良好的电化学循环性能。