Noble-metal efficient Pt-Ir-Co/SiO2 catalyst for selective hydrogenolytic ring opening of methylcyclopentane
Noble-metal efficient Pt-Ir-Co/SiO2 catalyst for selective hydrogenolytic ring opening of methylcyclopentane
复制标题
用于甲基环戊烷选择性氢解开环的贵金属高效 Pt-Ir-Co/SiO2 催化剂
DOI：
10.1016/j.cattod.2018.03.059
复制
发表时间：
2018-10-15
期刊：
影响因子：
5.3
通讯作者：
Xu, Bo-Qing
中科院分区：
文献类型：
--
作者：
Dong, Xiao;Zheng, Peng;Xu, Bo-Qing
采用原电池置换法（GR）制备了Pt-Co/SiO2和Pt-Ir-Co/SiO2催化剂，并将其用于甲基环戊烷（MCP）氢解开环反应。通过GR在较便宜的Co纳米颗粒（NP）表面选择性沉积贵金属，大大提高了活性较高的Pt或Pt和Ir原子选择性催化MCP开环反应的利用效率，与催化剂相比证明了这一点。传统浸渍制备。通过对制备溶液和固体样品中的组成变化的了解，定量地研究了GR的化学性质。GR催化剂的结构特征是高分散的Pt或Pt和Ir簇选择性沉积在Co NP表面。与浸渍法制备的催化剂相比，GR催化剂的质量比活性（MSANM）明显提高，这是由于Pt或Pt和Ir的利用效率显著提高。此外，Pt-Ir-Co/SiO2催化剂的MSANM明显高于Pt-Co/SiO2和Ir-Co/SiO2催化剂。这一观察结果的特点是高度分散的Pt和Ir簇之间的协同作用的催化，除了提高贵金属的利用效率。我们的催化数据似乎表明，二卡宾机制是占主导地位的GR催化剂的开环反应的MCP。
Pt-Co/SiO2 and Pt-Ir-Co/SiO2 catalysts were prepared via galvanic replacement (GR) and employed for the hydrogenolytic ring-opening of methylcyclopentane (MCP). Selective deposition of the noble metals at the less expensive Co nanoparticle (NP) surface by GR greatly enhanced the utilization efficiency of the more active Pt or Pt and Ir atoms for the selective catalysis to the ring-opening reaction of MCP, as justified by comparison with catalysts from conventional impregnation preparation. The chemistry of GR was quantitatively studied by comprehension of the composition changes both in the preparation solution and in the solid samples. The structural features of GR catalysts were characterized as highly dispersed Pt or Pt and Ir clusters selectively deposited on Co NP surface. Compared to their counterparts from impregnation preparation, the GR catalysts showed much higher mass-specific activity normalized by overall noble metal loading (MSANM), due to the significantly enhanced utilization efficiency of Pt or Pt and Ir. In addition, the trimetallic Pt-Ir-Co/SiO2 catalyst showed a distinctly higher MSANM than the bimetallic Pt-Co/SiO2 and Ir-Co/SiO2 ones. This observation features a synergy between the highly dispersed Pt and Ir clusters in the catalysis, besides the enhanced noble metal utilization efficiency. Our catalytic data seem to suggest that a dicarbene mechanism was prevailing over the GR catalysts for the ring-opening reaction of MCP.