含铜类水滑石催化材料热分解过程的研究(英文)

Study on the Thermal Decomposition of a Copper ContainingHydrotalcite like Catalytic Material

共沉淀法合成了Cu0.13Mg0 6Al0.27(OH)2(CO3)0.135·xH2O类水滑石物质 (CuHTlc) ,采用XRD、DTA TG、BET、TEM和27AlMASNMR技术对其热分解过程进行了表征。结果表明 ,在较低焙烧温度时 (低于300℃ ),氢氧根和层间水部分脱除 ,但水滑石仍保持其层状结构 ;500℃时 ,其层状结构被完全破坏 ,出现氧化镁晶相结构 ,随着焙烧温度的进一步升高 ,尖晶石晶相生成。500℃时的焙烧产物具有最大比表面 (193m2·g-1)。当温度高于500℃ ,焙烧产物组成可表示为Cu0.13Mg0.6Al0.27O0.135,CuHTlc的热分解过程可表示为 :Cu0.13Mg0.6Al0.27(OH)2(CO3)0.135·xH2O→Cu0.13Mg0.6Al0.27O0.135 +(1 +x)H2O +0.135CO2。

The hydrotalcite like compound Cu0.13Mg0.6Al0.27(OH)2(CO3)0.135·xH2O (CuHTlc) are synthesized by coprecipitation method and are characterized by XRD, DTA TG, BET, TEM and 27Al MAS NMR. The results show that at relatively low calcination temperatures (below 300℃), the layer structure of CuHTlc is retained, although partial dehydroxylation in addition to dehydration occurs. At 500℃, the hydrotalcite structure is destroyed and MgO phase appears,the spinel phase forms with the further increase of calcination temperature. CuHTlc calcined at 500℃has the highest surface area (193m2·g-1). When CuHTlc are calcined above 500℃, the composition of resusting products is Cu0.13Mg0.6Al0.27O0.135, the equation of thermal decoposition of CuHTlc can be expressed as following:Cu0.13Mg0.6Al0.27(OH)2(CO3)0.135·xH2O →Cu0.13Mg0.6Al0.27O0.135 +(1+x)H2O +0.135CO2.