摘要
采用过饱和沉淀法合成n(Mg)/n(Al)=2的Mg-Al类水滑石化合物(Mg-Al-HT),再用水热法将它与钛胶复合,制得Mg-Al-HT/TiO2异质复合光催化剂.采用X射线粉末衍射、透射电子显微镜、场发射扫描电子显微镜、低温N2吸附-脱附、紫外-可见漫反射光谱和热重等技术对催化剂结构、成分和性质进行了表征.结果表明,在波长365nm的紫外光照射降解苯的反应中,Mg-Al-HT/TiO2异质复合光催化剂表现出优于单一的TiO2或Mg-Al-HT催化剂的光催化活性,且稳定性更高;同时讨论了该复合催化剂性能优异的原因.另外,运用电子顺磁共振技术检测到体系中存在羟基自由基等活性物种,并据此提出了Mg-Al-HT/TiO2异质复合纳米晶催化剂光催化降解苯的反应机理.
Mg-Al hydrotalcite-like compounds （Mg-Al-HT） with Mg/Al molar ratio of 2 have been successfully synthesized by a supersaturated precipitation method and then mixed with a titania-sol to prepare nano-crystalline Mg-Al hydrotalcite-like compounds/TiO2 （Mg-Al-HT/TiO2） heterocompound photocatalysts by a hydrothermal method.The structure and components,Brunauer-Emmett-Teller specific surface area,and photoresponse of the photocatalysts were characterized by powder X-ray diffraction,transmission electron microscopy,field-emission scanning electron microscopy,N2 sorption,and ultraviolet-visible diffuse reflectance spectroscopy.The photocatalytic activity of the nano-crystalline Mg-Al-HT/TiO2 heterocompound photocatalysts for degradation of benzene was superior to that of single TiO2 or Mg-Al-HT under 365 nm light irradiation.The Mg-Al-HT/TiO2 heterocompound photocatalysts had higher stability.The electron paramagnetic resonance （EPR） technique was used to acquire the spin trapped-EPR spectra of the active species in the photocatalytic reaction.The possible photocatalytic reaction mechanism was also proposed.
出处
《催化学报》
SCIE
EI
CAS
CSCD
北大核心
2010年第8期1037-1043,共7页
基金
国家自然科学基金(20873023
20537010)
教育部长江学者和创新团队发展计划(PCSIRT0818)
关键词
镁铝类水滑石
二氧化钛
苯
异质复合物
光催化
magnesium-aluminium hydrotalcite-like compound
titanium dioxide
benzene
hetero compound
photocatalysis
