Yuan Dingwang, Cai Li, Xie Tuanping, Liao Heting, Hu Wangyu
Hunan University, College of Materials Science and Engineering, Changsha 410082, China.
Phys Chem Chem Phys. 2021 Apr 14;23(14):8653-8660. doi: 10.1039/d0cp05285j. Epub 2021 Mar 29.
The selective hydrogenation of acetylene was studied on the ordered Cu-Pd intermetallic compounds (L1-type CuPd, L1-type CuPd, and L1-type CuPd) and Pd-modified Cu(111) surfaces through first-principles calculations. The catalytic selectivity and activity of Cu-Pd alloy catalysts are closely related to the crystal structure and composition of Cu-Pd intermetallic compounds and the size of Pd ensembles of Cu-based dilute alloy surface for the selective hydrogenation of acetylene to ethylene. Significantly, we found that the ordered Cu-Pd alloy surface containing isolated Pd atoms (i.e., L1-type CuPd(111) surface) is highly efficient for the selective hydrogenation reaction of CH + H→ CH. The contiguous Pd atom ensembles (Pd dimer and trimer) are catalytically active towards CH + H → CH and CH + H → CH reactions than the single Pd atom on a Pd-decorated Cu(111) surface. However, the small Pd ensembles on Cu(111) present a low chemical activity for H dissociation compared with the ordered Cu-Pd intermetallic compounds. Our theoretical results provide a strategy of crystal phase and composition control for enhancing the selectivity and activity of Cu-Pd catalysts towards acetylene selective hydrogenation.
通过第一性原理计算，研究了有序铜钯金属间化合物（L1型CuPd、L1型CuPd和L1型CuPd）以及钯修饰的Cu(111)表面上乙炔的选择性加氢反应。对于乙炔选择性加氢生成乙烯的反应，铜钯合金催化剂的催化选择性和活性与铜钯金属间化合物的晶体结构和组成以及铜基稀合金表面钯原子簇的大小密切相关。值得注意的是，我们发现含有孤立钯原子的有序铜钯合金表面（即L1型CuPd(111)表面）对于CH + H→ CH的选择性加氢反应具有很高的效率。与钯修饰的Cu(111)表面上的单个钯原子相比，相邻的钯原子簇（钯二聚体和三聚体）对CH + H → CH和CH + H → CH反应具有催化活性。然而，与有序铜钯金属间化合物相比，Cu(111)表面上的小钯原子簇对氢解离的化学活性较低。我们的理论结果提供了一种通过控制晶相和组成来提高铜钯催化剂对乙炔选择性加氢的选择性和活性的策略。
