考察了α-Ga_(2)O_(3)、β-Ga_(2)O_(3)和γ-Ga_(2)O_(3)对CO_(2)氧化乙苯脱氢制苯乙烯反应的催化性能,并通过N_(2)吸附、XRD、NH_(3)-TPD、CO_(2)-TPD、^(71)Ga MAS NMR和TGA等多种方法对不同晶相Ga_(2)O_(3)催化剂进行表征,探究了催...考察了α-Ga_(2)O_(3)、β-Ga_(2)O_(3)和γ-Ga_(2)O_(3)对CO_(2)氧化乙苯脱氢制苯乙烯反应的催化性能,并通过N_(2)吸附、XRD、NH_(3)-TPD、CO_(2)-TPD、^(71)Ga MAS NMR和TGA等多种方法对不同晶相Ga_(2)O_(3)催化剂进行表征,探究了催化剂晶相结构与催化性能的关联。结果表明,Ga_(2)O_(3)的晶相结构与CO_(2)氧化乙苯脱氢性能密切相关,γ-Ga_(2)O_(3)表现出最佳的催化性能,在550℃乙苯转化率达54.7%,苯乙烯选择性为98.6%,循环使用6次后,催化活性仍无明显降低。γ-Ga_(2)O_(3)具有最多的中强酸位、最高的四配位Ga(Ⅳ)百分比和最大的比表面积与孔体积,有利于乙苯的吸附活化、C—H键的解离和催化剂容碳能力的提升,从而使其表现出最佳的催化性能。展开更多
The highly selective catalytic hydrogenation of halogenated nitroaromatics was achieved by employing Pd‑based catalysts that were co‑modified with organic and inorganic ligands.It was demonstrated that the catalysts c...The highly selective catalytic hydrogenation of halogenated nitroaromatics was achieved by employing Pd‑based catalysts that were co‑modified with organic and inorganic ligands.It was demonstrated that the catalysts contained Pd species in mixed valence states,with high valence Pd at the metal‑support interface and zero valence Pd at the metal surface.While the strong coordination of triphenylphosphine(PPh3)to Pd0 on the Pd surface prevents the adsorption of halogenated nitroaromatics and thus dehalogenation,the coordination of sodium metavanadate(NaVO3)to high‑valence Pd sites at the interface helps to activate H2 in a heterolytic pathway for the selective hydrogenation of nitro‑groups.The excellent catalytic performance of the interfacial active sites enables the selective hydrogenation of a wide range of halogenated nitroaromatics.展开更多
文摘考察了α-Ga_(2)O_(3)、β-Ga_(2)O_(3)和γ-Ga_(2)O_(3)对CO_(2)氧化乙苯脱氢制苯乙烯反应的催化性能,并通过N_(2)吸附、XRD、NH_(3)-TPD、CO_(2)-TPD、^(71)Ga MAS NMR和TGA等多种方法对不同晶相Ga_(2)O_(3)催化剂进行表征,探究了催化剂晶相结构与催化性能的关联。结果表明,Ga_(2)O_(3)的晶相结构与CO_(2)氧化乙苯脱氢性能密切相关,γ-Ga_(2)O_(3)表现出最佳的催化性能,在550℃乙苯转化率达54.7%,苯乙烯选择性为98.6%,循环使用6次后,催化活性仍无明显降低。γ-Ga_(2)O_(3)具有最多的中强酸位、最高的四配位Ga(Ⅳ)百分比和最大的比表面积与孔体积,有利于乙苯的吸附活化、C—H键的解离和催化剂容碳能力的提升,从而使其表现出最佳的催化性能。
文摘The highly selective catalytic hydrogenation of halogenated nitroaromatics was achieved by employing Pd‑based catalysts that were co‑modified with organic and inorganic ligands.It was demonstrated that the catalysts contained Pd species in mixed valence states,with high valence Pd at the metal‑support interface and zero valence Pd at the metal surface.While the strong coordination of triphenylphosphine(PPh3)to Pd0 on the Pd surface prevents the adsorption of halogenated nitroaromatics and thus dehalogenation,the coordination of sodium metavanadate(NaVO3)to high‑valence Pd sites at the interface helps to activate H2 in a heterolytic pathway for the selective hydrogenation of nitro‑groups.The excellent catalytic performance of the interfacial active sites enables the selective hydrogenation of a wide range of halogenated nitroaromatics.
