Physicochemical Stabilization of Pt against Sintering for a Dehydrogenation Catalyst with High Activity, Selectivity, and Durability
Physicochemical Stabilization of Pt against Sintering for a Dehydrogenation Catalyst with High Activity, Selectivity, and Durability
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DOI：
10.1021/acscatal.6b00329
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发表时间：
2016-05-01
期刊：
影响因子：
12.9
通讯作者：
Choi, Minkee
中科院分区：
文献类型：
--
作者：
Im, Juhwan;Choi, Minkee
抑制催化剂的不可逆失活是多相催化的关键。特别地，经由活性位点的烧结的失活对于涉及苛刻的反应/再生条件的反应是重要的问题。在这项工作中，我们开发了一种PtGa/γ-Al 2 O3烷烃脱氢催化剂，通过在苛刻条件下（反应/再生在>823 K）显着抑制Pt烧结，具有非常高的活性，选择性和长期稳定性。为了稳定Pt，物理和化学稳定策略协同组合。对于前者，通过溶胶-凝胶化学法在γ-Al_2O_3的合成过程中引入Pt，由于Pt在γ-Al_2O_3中的部分包埋，可以增加Pt和γ-Al_2O_3之间的界面接触。对于后者，原子分散的Ce掺杂在γ-Al_2O_3上，这可以通过强Pt-O-Ce相互作用来稳定Pt。由于有效的Pt稳定，催化剂在重复的反应循环中显示出非常稳定的活性和选择性行为，尽管催化剂通过简单的氧化而不是工业上使用的氧氯化来再生。在这项工作中报告的Pt稳定策略可以应用到其他金属催化的反应，涉及严重的反应/再生条件。
Suppressing irreversible catalyst deactivation is critical in heterogeneous catalysis. In particular, deactivation via sintering of active sites is a significant issue for reactions involving harsh reaction/regeneration conditions. In this work, we developed a PtGa/gamma-Al2O3 alkane dehydrogenation catalyst with exceptionally high activity, selectivity, and long-term stability by markedly suppressing Pt sintering under harsh conditions (reaction/regeneration at >823 K). To stabilize Pt, physical and chemical stabilization strategies were synergistically combined. For the former, Pt was introduced during the synthesis of gamma-Al2O3 via sol gel chemistry, which can increase the interfacial contact between Pt and gamma-Al2O3 due to the partial entrapment of Pt in gamma-Al2O3. For the latter, atomically dispersed Ce was doped on gamma-Al2O3, which can stabilize Pt via strong Pt-O-Ce interactions. Because of effective Pt stabilization, the catalyst showed remarkably steady activity and selectivity behaviors over the repeated reaction cycles, although the catalyst is regenerated via simple oxidation rather than industrially used oxychlorination. The Pt stabilization strategies reported in this work can be applied to other metal-catalyzed reactions that involve severe reaction/regeneration conditions.