化学研究与应用
化學研究與應用
화학연구여응용
CHEMICAL RESEARCH AND APPLICATION
2001年
2期
141-144
,共4页
李大塘%郭军%邓谦%邓立元%罗娟
李大塘%郭軍%鄧謙%鄧立元%囉娟
리대당%곽군%산겸%산립원%라연
微量吸附量热%Cu-Al水滑石%Cu(Al)O复合物%表面酸碱性
微量吸附量熱%Cu-Al水滑石%Cu(Al)O複閤物%錶麵痠堿性
미량흡부량열%Cu-Al수활석%Cu(Al)O복합물%표면산감성
673K分解Cu/Al物质的量比分别为0.5、1和2的Cu-Al水滑石转化为Cu(Al)O复合物。XRD测定仅显示CuO物相,表明组成成分较均一。微量吸附量热法测定Cu(Al)O复合物表面酸碱中心的强度和数量,给出了吸附分子CO2/NH3的吸附曲线。量热结果展示,样品的酸中心强度顺序是:0.5CAO>CAO>2CAO,而碱中心强度顺序是:0.5CAO<CAO<2CAO。显然,样品的酸性(碱性)随着Al(Cu)含量的提高而逐渐增强。研究表明,样品的NH3和CO2起始吸附热与其Sanderson电负性线性相关。
673K分解Cu/Al物質的量比分彆為0.5、1和2的Cu-Al水滑石轉化為Cu(Al)O複閤物。XRD測定僅顯示CuO物相,錶明組成成分較均一。微量吸附量熱法測定Cu(Al)O複閤物錶麵痠堿中心的彊度和數量,給齣瞭吸附分子CO2/NH3的吸附麯線。量熱結果展示,樣品的痠中心彊度順序是:0.5CAO>CAO>2CAO,而堿中心彊度順序是:0.5CAO<CAO<2CAO。顯然,樣品的痠性(堿性)隨著Al(Cu)含量的提高而逐漸增彊。研究錶明,樣品的NH3和CO2起始吸附熱與其Sanderson電負性線性相關。
673K분해Cu/Al물질적량비분별위0.5、1화2적Cu-Al수활석전화위Cu(Al)O복합물。XRD측정부현시CuO물상,표명조성성분교균일。미량흡부량열법측정Cu(Al)O복합물표면산감중심적강도화수량,급출료흡부분자CO2/NH3적흡부곡선。량열결과전시,양품적산중심강도순서시:0.5CAO>CAO>2CAO,이감중심강도순서시:0.5CAO<CAO<2CAO。현연,양품적산성(감성)수착Al(Cu)함량적제고이축점증강。연구표명,양품적NH3화CO2기시흡부열여기Sanderson전부성선성상관。
A series of copper-aluminium hydrotalcites,with Cu/Al ratios by weight 0.5、1 and 2,was synthesized by using a sodium carbonate solution as the precipitating reagent through the coprecipitaion method.After calcination at 673K,the hydrotalcites were converted into Cu(Al)O composite oxides,showing only the patterns of CuO by X-ray diffraction measurements.Microcalorimetric measurements of NH3 and CO2 adsorptions were used to determine the strength of acid and base sites on copper-aluminium composite oxides,and adsorption curves were given coneurently.The results revealed that the acidity sequence is 0.5CAO>CAO>2CAO,while basicity order is 0.5CAO<CAO<2CAO.It is obvious that the increase of the Cu/Al amount of substance ratios enhanced the surface basicity while reduced the surface acidity of the composite oxides.The initial heats of NH3 and CO2 adsorption were found to be proportional to Sanderson electronegativities of the samples.