Highly Selective and Sharp Volcano-type Synergistic Ni2Pt@ZIF-8-Catalyzed Hydrogen Evolution from Ammonia Borane Hydrolysis
Highly Selective and Sharp Volcano-type Synergistic Ni2Pt@ZIF-8-Catalyzed Hydrogen Evolution from Ammonia Borane Hydrolysis
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DOI：
10.1021/jacs.8b06511
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发表时间：
2018-08-08
影响因子：
15
通讯作者：
Astruc, Didier
中科院分区：
文献类型：
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作者：
Fu, Fangyu;Wang, Changlong;Astruc, Didier
如果有效催化，氨硼烷水解被认为是一种安全、快速生产 H-2 的潜在方法。这里引入了一系列几乎单分散的合金双金属纳米粒子催化剂，并在过渡金属中进行了优化，发现其极其有效和高选择性，并且嵌入沸石咪唑酯骨架 (ZIF-8) 载体内的 2/3 Ni 和 1/3 Pt 之间具有明显的正协同作用。这些催化剂比在这种载体上单独使用 Ni 或 Pt 类似物更有效地释放 H-2，例如，最好的催化剂 Ni2Pt@ZiF-8 的 TOF 达到 600 mol(H2).mol(catal)(-1)。 min(-1) 和 2222 mol(H2).mol(pt)(-1)min(-1) 在环境条件下，超越了以前的 Pt 基催化剂的性能。 NaOH 的存在促进了 Ni2Pt@ZiF-8 催化剂上 H-2 的释放，其速度比不存在时快 87 倍，而 NaOH 则减少了相关 Pt@ZiF-8 催化剂上 H-2 的释放。 ZIF-8 载体显得出色，并且比其他载体（包括氧化石墨烯、活性炭和带有这些纳米颗粒的 SBA-15）要高效得多。特别涉及使用 D2O 的动力学同位素效应的机理研究表明，通过将水的 O-H 键氧化加成到催化剂表面上而发生裂解是该反应的速率决定步骤。 Ni2Pt@ZiF-8 卓越的催化活性已被用于以氨硼烷作为 H-2 源的成功串联催化加氢反应。总之，这里公开的选择性和显着的协同作用以及机械结果应该会在催化剂设计方面取得重大进展，以在不久的将来从富氢基质方便地产生氢气。
Ammonia borane hydrolysis is considered as a potential means of safe and fast method of H-2 production if it is efficiently catalyzed. Here a series of nearly monodispersed alloyed bimetallic nanoparticle catalysts are introduced, optimized among transition metals, and found to be extremely efficient and highly selective with sharp positive synergy between 2/3 Ni and 1/3 Pt embedded inside a zeolitic imidazolate framework (ZIF-8) support. These catalysts are much more efficient for H-2 release than either Ni or Pt analogues alone on this support, and for instance the best catalyst Ni2Pt@ZiF-8 achieves a TOF of 600 mol(H2).mol(catal)(-1). min(-1) and 2222 mol(H2).mol(pt)(-1)min(-1) under ambient conditions, which overtakes performances of previous Pt-base catalysts. The presence of NaOH boosts H-2 evolution that becomes 87 times faster than in its absence with Ni2Pt@ZiF-8, whereas NaOH decreases H-2 evolution on the related Pt@ZiF-8 catalyst. The ZIF-8 support appears outstanding and much more efficient than other supports including graphene oxide, active carbon and SBA-15 with these nanoparticles. Mechanistic studies especially involving kinetic isotope effects using D2O show that cleavage by oxidative addition of an O-H bond of water onto the catalyst surface is the rate-determining step of this reaction. The remarkable catalyst activity of Ni2Pt@ZiF-8 has been exploited for successful tandem catalytic hydrogenation reactions using ammonia borane as H-2 source. In conclusion the selective and remarkable synergy disclosed here together with the mechanistic results should allow significant progress in catalyst design toward convenient H2 generation from hydrogen-rich substrates in the close future.