Flame spray pyrolysis （FSP） was utilized to synthesize Ce-Mn oxides in one step for catalytic oxidation of benzene. Cerium acetate and manganese acetate were used as precursors. The materials synthesized were charac...Flame spray pyrolysis （FSP） was utilized to synthesize Ce-Mn oxides in one step for catalytic oxidation of benzene. Cerium acetate and manganese acetate were used as precursors. The materials synthesized were characterized using X-ray diffraction （XRD）, N2 adsorption, X-ray photoelectron spectroscopy （XPS）, transmission electron microscopy （TEM）, Raman spectroscopy, and H2-temperature programmed reduc- tion （H2-TPR） and their benzene catalytic oxidation behavior was evaluated. Mn ions were evidenced in multiple chemical states. Crystalline Ce-Mn oxides consist of particles with size 〈40 nm and specific sur- face areas （SSA） of 20-50 m2/g. Raman spectrums and H2-TPR results indicated the interaction between cerium and manganese oxides. Flame-made 12.5%-Ce-Mn oxide exhibited excellent catalytic activity at relatively low temperatures （T95 about 260℃） compared to other Ce-Mn oxides with different cerium- to-manganese ratios, Redox mechanism and strong interaction conform to structure analysis that Ce-Mn strong interaction formed during the high temperature flame process and the results were used to explain catalytic oxidation of benzene.展开更多
A simple and selective method using a column packed with graphene oxide（GO） as a solid phase extractant has been developed for the multi-element preconcentration of Fe（Ⅲ）,Ni（Ⅱ）,Cu（Ⅱ） and Zn（Ⅱ）ions prior ...A simple and selective method using a column packed with graphene oxide（GO） as a solid phase extractant has been developed for the multi-element preconcentration of Fe（Ⅲ）,Ni（Ⅱ）,Cu（Ⅱ） and Zn（Ⅱ）ions prior to flame atomic absorption spectrometric determinations.The method is based on the sorption of mentioned ions on synthesized GO using 2-（tert-butoxy）-N-（3-carbamothioylphenyl）acetamide as a chelating agent.Several parameters on the extraction and complex formation were optimized.Under the optimized conditions（pH 6,flow rate 9 mL/min）,metal ions were retained on the column,then quantitatively eluted by HNO3solution（5 mL,3.0 mol/L）.The preconcentration factor was calculated as250.The detection limits for the analyte ions of interest were found in the range of 0.11 ng/mL（Ni2＋） to0.63 ng/mL（Cu2＋）.The column packed with GO was adequate for metal ions separation in matrixes containing alkali,alkaline earth,transition and heavy metal ions.展开更多
基金financial supports from National Nature Science Foundation of China(Grant No.51002154)Instrument Developing Project of the Chinese Academy of Sciences(Grant No.YZ200722)+2 种基金National High Technology Research and Development Program of China(Grant Nos.2012AA062702, 2010AA064903)the 12th Five-Year National Key Technology R&D Program(Grant Nos.2012BAJ02B03,2012BAJ02B07)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB05050300)
文摘Flame spray pyrolysis （FSP） was utilized to synthesize Ce-Mn oxides in one step for catalytic oxidation of benzene. Cerium acetate and manganese acetate were used as precursors. The materials synthesized were characterized using X-ray diffraction （XRD）, N2 adsorption, X-ray photoelectron spectroscopy （XPS）, transmission electron microscopy （TEM）, Raman spectroscopy, and H2-temperature programmed reduc- tion （H2-TPR） and their benzene catalytic oxidation behavior was evaluated. Mn ions were evidenced in multiple chemical states. Crystalline Ce-Mn oxides consist of particles with size 〈40 nm and specific sur- face areas （SSA） of 20-50 m2/g. Raman spectrums and H2-TPR results indicated the interaction between cerium and manganese oxides. Flame-made 12.5%-Ce-Mn oxide exhibited excellent catalytic activity at relatively low temperatures （T95 about 260℃） compared to other Ce-Mn oxides with different cerium- to-manganese ratios, Redox mechanism and strong interaction conform to structure analysis that Ce-Mn strong interaction formed during the high temperature flame process and the results were used to explain catalytic oxidation of benzene.
文摘A simple and selective method using a column packed with graphene oxide（GO） as a solid phase extractant has been developed for the multi-element preconcentration of Fe（Ⅲ）,Ni（Ⅱ）,Cu（Ⅱ） and Zn（Ⅱ）ions prior to flame atomic absorption spectrometric determinations.The method is based on the sorption of mentioned ions on synthesized GO using 2-（tert-butoxy）-N-（3-carbamothioylphenyl）acetamide as a chelating agent.Several parameters on the extraction and complex formation were optimized.Under the optimized conditions（pH 6,flow rate 9 mL/min）,metal ions were retained on the column,then quantitatively eluted by HNO3solution（5 mL,3.0 mol/L）.The preconcentration factor was calculated as250.The detection limits for the analyte ions of interest were found in the range of 0.11 ng/mL（Ni2＋） to0.63 ng/mL（Cu2＋）.The column packed with GO was adequate for metal ions separation in matrixes containing alkali,alkaline earth,transition and heavy metal ions.
