Pt/TiH2 Catalyst for Ionic Hydrogenation via Stored Hydrides in the Presence of Gaseous H2,ACS Catalysis

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Pt/TiH2 Catalyst for Ionic Hydrogenation via Stored Hydrides in the Presence of Gaseous H2
ACS Catalysis ( IF 11.3 ) Pub Date : 2019-06-14 00:00:00 , DOI: 10.1021/acscatal.9b00917
Qifan Wu _{1,

2,

3} , Chao Zhang _{1,

3} , Masahiko Arai _{1,

3} , Bin Zhang _{1,

2,

3} , Ruhui Shi _{1,

2,

3} , Peixuan Wu _{1,

2,

3} , Zhuangqing Wang _{1,

2,

3} , Qiang Liu _{1,

3} , Ke Liu _{1,

3} , Weiwei Lin _{1,

3} , Haiyang Cheng _{1,

3} , Fengyu Zhao _{1,

3}

Affiliation

A Pt/TiH₂ catalyst having hydrogen storage and release capability was investigated for selective hydrogenation of trans-cinnamaldehyde (CAL) to cinnamyl alcohol (COL) with gaseous dihydrogen. The catalytic behavior of this catalyst was significantly different from that of a reference Pt/TiO₂ catalyst with respect to the product selectivity and the hydrogenation mechanism. The Pt/TiH₂ catalyst showed a COL selectivity of 97% at a CAL conversion of 98%, which was ascribed to the function of a Pt crystallite–support boundary layer that caused the preferential adsorption of CAL with its carbonyl group. Furthermore, the carbonyl group was hydrogenated by hydride species (H⁺, H^–) supplied from the support and the hydride species consumed were compensated from gaseous dihydrogen; hydrogen atoms were formed by ordinary homolytic cleavage on Pt and then these hydrogen atoms moved onto the surface of TiH₂ and diffused into the bulk of the support, during which those simultaneously changed to hydride species (H⁺, H^–) via electron transfer with titanium species and hydride vacancies therein. The surface and bulk diffusion of the hydrogen atoms from Pt to TiH₂ support should be the dominant step rather than their addition to the carbonyl group of CAL (ordinary hydrogenation). That is, ionic hydrogenation occurs with Pt/TiH₂ in the presence of gaseous dihydrogen.

中文翻译：

在气态H ₂存在下通过储存的氢化物进行离子加氢的Pt / TiH ₂催化剂

的Pt / TIH ₂催化剂具有氢的储存和释放能力进行了研究用于选择性氢化反-cinnamaldehyde（CAL）到肉桂醇（COL）与气态二氢。就产物选择性和氢化机理而言，该催化剂的催化行为与参考Pt / TiO ₂催化剂明显不同。Pt / TiH ₂催化剂在CAL转化率为98％时显示出97％的COL选择性，这归因于Pt晶体-载体边界层的功能，该边界层导致CAL优先被其羰基吸附。此外，羰基的氢化物物种（H氢化⁺，H ^-）从载体中提供，消耗的氢化物通过气态二氢得到补偿；的氢原子被普通均裂在Pt形成，然后将这些氢原子移动到载通的表面₂和扩散到本体的支持，在此期间，那些同时改变到氢化物种（H ⁺，H ^-）经由电子转移与钛物种和其中的氢化物空位。氢原子从Pt到TiH ₂载体的表面和整体扩散应该是主要步骤，而不是将它们加到CAL的羰基上（常规氢化）。即，在气态二氢存在下，Pt / TiH ₂发生离子氢化。

更新日期：2019-06-14

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