采用等体积浸渍法制备了不同钒负载量的VOX/Mg-Al-O催化剂,采用XRD、氮气吸附-脱附、FT-IR、H2-TPR等催化剂表征方法对所制备的催化剂进行分析表征,并将催化剂用于环己烷脱氢的催化反应,以研究催化剂表面物种性质与其氧化脱氢反应性能...采用等体积浸渍法制备了不同钒负载量的VOX/Mg-Al-O催化剂,采用XRD、氮气吸附-脱附、FT-IR、H2-TPR等催化剂表征方法对所制备的催化剂进行分析表征,并将催化剂用于环己烷脱氢的催化反应,以研究催化剂表面物种性质与其氧化脱氢反应性能之间的关系。结果表明:当钒负载量为4%左右时,催化剂表面以还原性能好、单层分散的孤立态和聚合态钒氧物种为主;当钒负载量高于4%时,催化剂表面开始形成还原性能较差的镁钒酸盐物种。当采用4 VOX/Mg-Al-O催化剂、反应温度475℃、烃氧比为2、空气流量100 m L/min的操作条件下,在催化剂表面所形成的低价钒氧物种为环己烷脱氢反应的活性物种,可获得较好的环己烷氧化脱氢制取环己烯的催化性能。展开更多
A series of VOx/CeO2 catalysts we re synthesized via vanadia supported on ceria with different BET surface areas.The catalysts were employed to investigate the active sites for the selective catalytic reduction of NO ...A series of VOx/CeO2 catalysts we re synthesized via vanadia supported on ceria with different BET surface areas.The catalysts were employed to investigate the active sites for the selective catalytic reduction of NO with NH3(NH3-SCR).The kinetic results show that VOx/CeO2 catalysts exhibit nearly constant apparent activation energies(Ea),indicating the same SCR reaction mechanism.The V-O-Ce bridging modes and oligomeric VOx were identified and quantified by Raman,FT-IR and H2-TPR.The amounts of the V-O-Ce bridging modes calculated by H2-TPR are correlated to the NH3-SCR intrinsic reaction rates.The turnover frequencies(TOFs) show a constant value at the same temperature,which were calculated based on the number of V-O-Ce bridging modes of VOx/CeO2 catalysts.Therefore,it can be concluded that the V-O-Ce bridging modes are the active sites of VOx/CeO2 catalysts for the NH3-SCR reaction.展开更多
文摘采用等体积浸渍法制备了不同钒负载量的VOX/Mg-Al-O催化剂,采用XRD、氮气吸附-脱附、FT-IR、H2-TPR等催化剂表征方法对所制备的催化剂进行分析表征,并将催化剂用于环己烷脱氢的催化反应,以研究催化剂表面物种性质与其氧化脱氢反应性能之间的关系。结果表明:当钒负载量为4%左右时,催化剂表面以还原性能好、单层分散的孤立态和聚合态钒氧物种为主;当钒负载量高于4%时,催化剂表面开始形成还原性能较差的镁钒酸盐物种。当采用4 VOX/Mg-Al-O催化剂、反应温度475℃、烃氧比为2、空气流量100 m L/min的操作条件下,在催化剂表面所形成的低价钒氧物种为环己烷脱氢反应的活性物种,可获得较好的环己烷氧化脱氢制取环己烯的催化性能。
基金Project supported by the National Key Research and Development Program (2017YFC0211302)China Huadian Science and Technology Institute (CHDI.KJ-20)。
文摘A series of VOx/CeO2 catalysts we re synthesized via vanadia supported on ceria with different BET surface areas.The catalysts were employed to investigate the active sites for the selective catalytic reduction of NO with NH3(NH3-SCR).The kinetic results show that VOx/CeO2 catalysts exhibit nearly constant apparent activation energies(Ea),indicating the same SCR reaction mechanism.The V-O-Ce bridging modes and oligomeric VOx were identified and quantified by Raman,FT-IR and H2-TPR.The amounts of the V-O-Ce bridging modes calculated by H2-TPR are correlated to the NH3-SCR intrinsic reaction rates.The turnover frequencies(TOFs) show a constant value at the same temperature,which were calculated based on the number of V-O-Ce bridging modes of VOx/CeO2 catalysts.Therefore,it can be concluded that the V-O-Ce bridging modes are the active sites of VOx/CeO2 catalysts for the NH3-SCR reaction.
