Synthesis and characterization of aluminum and AI/REE pillared clays and supported palladium catalysts for benzene oxidation

Volatile organic compounds (VOCs) are considered as a major pollutant in indoor and outdoor air.More stringent environmental regulations have been implemented in order to reduce the VOC emissions.One of the techniques available for destructive removal of VOCs is catalytic oxidation.In the present work,Al/Rare Earths (REE: Y,Ce,La,Pr and Nd) pillared clays (PILCs) were used to support 0.2 wt.% of palladium for the complete oxidation of low concentration of benzene.The supports and catalysts were characterized by XRD,N2 adsorp-tion/desorption,FTIR spectroscopy,HRTEM and H2-TPR techniques.The results indicated that after Al and Al/REE pillaring,the basal spac-ing,SBET,Amic and Vmic of Al and AlREE-PILC had a considerable increase compared with those of Na-mmt.Activity tests of deep oxidation of benzene showed that the catalytic activity of Pd catalysts supported on Al and AlREE-PILC were much higher than that on initial clays,which was due to the fact that optimized structure of PILCs,such as large basal spacing,high SBET and porosity,improved Pd dispersion and increased the active sites of Pd.Especially for Pd/AlCe-PILC,the temperature of complete oxidation was about 280 oC,exhibiting the highest catalytic activity.     

Synthesis and characterization of aluminum and Al/REE pillared clays and supported palladium catalysts for benzene oxidation

Volatile organic compounds (VOCs) are considered as a major pollutant in indoor and outdoor air.More stringent environmental regulations have been implemented in order to reduce the VOC emissions.One of the techniques available for destructive removal of VOCs is catalytic oxidation.In the present work,Al/Rare Earths (REE: Y,Ce,La,Pr and Nd) pillared clays (PILCs) were used to support 0.2 wt.% of palladium for the complete oxidation of low concentration of benzene.The supports and catalysts were characterize...     

Ce修饰Na Y分子筛负载PdO纳米晶催化剂用于苯的催化氧化反应

以CeO_2修饰多孔NaY分子筛作为载体,采用高温液相还原法制备纳米晶PdO催化剂,用于低浓度苯催化氧化反应。采用XRD、N2吸附-脱附、透射电镜-能谱(HRTEM-EDS)、H2程序升温还原(H_2-TPR)、O_2程序升温脱附(O_2-TPD)和程序升温表面反应(TPSR)等对载体和催化剂进行表征。结果表明,NaY分子筛结构稳定,比表面积651 m~2·g~(-1)和孔容0. 326 cm~3·g~(-1),纳米晶PdO能够较均匀地分散在NaY载体上,颗粒尺寸约(3～5) nm。加入一定量CeO_2后,Pd O以较小的纳米晶颗粒形式分散在CeO_2周围,活性组分与助剂协同作用促进了催化剂中晶格氧的流动性,明显改善了0. 2%Pd/NaY的氧化性能。0. 2%Pd/8%Ce/NaY表现出最佳催化活性和良好稳定性,250℃可完全催化降解1000×10~(-6)的苯,并且230℃连续反应100 h,催化剂转化率稳定在86%。