Kim Ja Young, Jo Youngshin, Kim Ji Dang, Choi Myong Yong, Lee Sunwoo, Choi Hyun Chul
Department of Chemistry, Chonnam National University, Gwangju, 61186, South Korea.
Core-Facility Center for Photochemistry & Nanomaterials, Department of Chemistry, Research Institute of Natural Sciences, Gyeongsang National University, Jinju, 52828, South Korea.
Chemosphere. 2022 Nov;307(Pt 3):135838. doi: 10.1016/j.chemosphere.2022.135838. Epub 2022 Aug 10.
This study explored the impact of gas treatments on the structures of multi-walled carbon nanotubes supported Pd (CNT-Pd) catalysts used for electrocatalytic HO reduction and the Heck cross-coupling reaction. The CNT-Pd catalyst was prepared by anchoring Pd nanoparticles on thiolated CNTs. XPS was conducted to examine the surface composition and electronic structure changes of the CNT-Pd catalyst before and after gas treatment. The XPS results revealed that as-prepared CNT-Pd contains at least two different oxidation states on the surface, whereon their proportions depend on the gas used for treatment. Treatment with H leads to Pd(0) enrichment near the surface, while O treatment causes Pd(Ⅱ) enrichment of CNT-Pd. All catalysts containing both Pd(0) and Pd(Ⅱ) were active toward HO reduction, and the Heck cross-coupling reaction of n-butyl acrylate and 4-iodotoluene; increased proportion of metallic Pd(0) boosted the catalytic reaction. However, the catalyst stability increased as the amount of Pd(II) increased.
本研究探讨了气体处理对用于电催化还原 HO 和 Heck 交叉偶联反应的多壁碳纳米管负载 Pd（CNT-Pd）催化剂结构的影响。通过将 Pd 纳米颗粒锚定在硫醇化的 CNT 上来制备 CNT-Pd 催化剂。进行 XPS 以检查气体处理前后 CNT-Pd 催化剂的表面组成和电子结构变化。XPS 结果表明，制备的 CNT-Pd 在表面至少包含两种不同的氧化态，其比例取决于用于处理的气体。用 H 处理导致表面附近 Pd(0)富集，而 O 处理导致 CNT-Pd 的 Pd(Ⅱ)富集。所有含有 Pd(0)和 Pd(Ⅱ)的催化剂对 HO 还原以及丙烯酸正丁酯与 4-碘甲苯的 Heck 交叉偶联反应均具有活性；金属 Pd(0)比例的增加促进了催化反应。然而，随着 Pd(II)含量的增加，催化剂稳定性增强。
