α‐,β‐,δ‐,andγ‐MnO2nanocrystals are successfully prepared.We then evaluated the NH3selective catalytic reduction(SCR)performance of the MnO2catalysts with different phases.The NOx conversion efficiency decrease...α‐,β‐,δ‐,andγ‐MnO2nanocrystals are successfully prepared.We then evaluated the NH3selective catalytic reduction(SCR)performance of the MnO2catalysts with different phases.The NOx conversion efficiency decreased in the order:γ‐MnO2>α‐MnO2>δ‐MnO2>β‐MnO2.The NOx conversion with the use ofγ‐MnO2andα‐MnO2catalysts reached90%in the temperature range of140–200°C,while that based onβ‐MnO2reached only40%at200°C.Theγ‐MnO2andα‐MnO2nanowire crystal morphologies enabled good dispersion of the catalysts and resulted in a relatively high specific surface area.We found thatγ‐MnO2andα‐MnO2possessed stronger reducing abilities and more and stronger acidic sites than the other catalysts.In addition,more chemisorbed oxygen existed on the surface of theγ‐MnO2andα‐MnO2catalysts.Theγ‐MnO2andα‐MnO2catalysts showed excellent performance in the low‐temperature SCR of NO to N2with NH3.展开更多
基金supported by the National Natural Science Foundation of China(51502221)~~
文摘α‐,β‐,δ‐,andγ‐MnO2nanocrystals are successfully prepared.We then evaluated the NH3selective catalytic reduction(SCR)performance of the MnO2catalysts with different phases.The NOx conversion efficiency decreased in the order:γ‐MnO2>α‐MnO2>δ‐MnO2>β‐MnO2.The NOx conversion with the use ofγ‐MnO2andα‐MnO2catalysts reached90%in the temperature range of140–200°C,while that based onβ‐MnO2reached only40%at200°C.Theγ‐MnO2andα‐MnO2nanowire crystal morphologies enabled good dispersion of the catalysts and resulted in a relatively high specific surface area.We found thatγ‐MnO2andα‐MnO2possessed stronger reducing abilities and more and stronger acidic sites than the other catalysts.In addition,more chemisorbed oxygen existed on the surface of theγ‐MnO2andα‐MnO2catalysts.Theγ‐MnO2andα‐MnO2catalysts showed excellent performance in the low‐temperature SCR of NO to N2with NH3.
基金National Natural Science Fundation of China(21006073)Shanghai Rising-Star Program(11QA1407200)+1 种基金open-project program of the State Key Laboratory of Chemical Engineering(SKL-ChE-08C07)Shanghai Leading Academic Discipline Project(B303)~~
文摘利用催化气相化学沉积(Catalytic chemical vapor deposition,CCVD)法在炭纸上原位生长得到CNF/CP复合体,并对这种复合体的物理化学性能和氧气电催化还原反应(Oxygen reduction reaction,ORR)性能进行了研究。结果表明:纳米炭纤维较为均匀地分散在炭纸上,其中纳米炭纤维具有窄的直径分布。所制CNF/CP复合体具有较大的比表面积和独特的中孔结构;相对于炭纸,CNF/CP复合体的端面碳原子和基面碳原子比例较高。另外,CNF/CP还具有较高的ORR反应活性,其ORR为2电子反应过程,原因可以归结于纳米炭纤维独特的微结构。同时,CNF/CP也具有较高的交换电流密度和较正的平衡电压。
