Mahnaz Fatima, Mostafa-Al-Momin Mohammad, Rubel Md, Ferdous Md, Azam Md Shafiul
Department of Chemistry, Bangladesh University of Engineering and Technology (BUET) Dhaka 1000 Bangladesh
Department of Chemical Engineering, Bangladesh University of Engineering and Technology (BUET) Dhaka 1000 Bangladesh.
RSC Adv. 2019 Sep 25;9(52):30358-30369. doi: 10.1039/c9ra05736f. eCollection 2019 Sep 23.
Bimetallic nanocatalysts have been gaining huge research attention in the heterogeneous catalysis community recently owing to their tunable properties and multifunctional characteristics. In this work, we fabricated a bimetallic core-shell nanocomposite catalyst by employing a mussel-inspired strategy for immobilizing gold nanoparticles (AuNP) on the surface of nickel nanoparticles (NiNP). NiNPs obtained from the reduction of Ni(ii) were first coated with polydopamine to provide the anchoring sites towards the robust immobilization of AuNPs. The as-synthesized nanocomposite (Ni-PD-Au) exhibited outstanding catalytic activity while reducing methylene blue (MB) and 4-nitrophenol (4-NP) yielding rate constants 13.11 min and 4.21 min, respectively, outperforming the catalytic efficiency of its monometallic counterparts and other similar reported catalysts by large margins. The superior catalytic efficiency of the Ni-PD-Au was attributed to the well-known synergistic effect, which was experimentally investigated and compared with prior reports. Similar bio-inspired immobilization of AuNPs was also applied on graphene-wrapped NiNPs (Ni-G) instead of bare NiNPs to synthesize another composite catalyst (Ni-G-PD-Au), which yet again exhibited synergistic catalytic activity. A comparative study between the two nanocomposites suggested that Ni-PD-Au excelled in catalytic activity but Ni-G-PD-Au provided noteworthy stability showing ∼100% efficiency over 17 repeated cycles. However, along with excellent synergistic performance, both nanocomposites demonstrated high magnetization and thermal stability up to 350 °C ascertaining their easy separation and sustainability for high-temperature applications, respectively.
由于其可调谐性能和多功能特性，双金属纳米催化剂最近在多相催化领域引起了广泛的研究关注。在这项工作中，我们采用一种受贻贝启发的策略，将金纳米颗粒（AuNP）固定在镍纳米颗粒（NiNP）表面，制备了一种双金属核壳纳米复合催化剂。通过还原Ni(ii)得到的NiNPs首先用聚多巴胺包覆，为牢固固定AuNPs提供锚固位点。合成的纳米复合材料（Ni-PD-Au）在还原亚甲基蓝（MB）和4-硝基苯酚（4-NP）时表现出优异的催化活性，产率常数分别为13.11 min和4.21 min，大大超过了其单金属对应物和其他类似报道催化剂的催化效率。Ni-PD-Au的优异催化效率归因于众所周知的协同效应，我们对其进行了实验研究并与先前的报道进行了比较。类似的受生物启发的AuNPs固定方法也应用于石墨烯包裹的NiNPs（Ni-G）而不是裸NiNPs上，以合成另一种复合催化剂（Ni-G-PD-Au），该催化剂再次表现出协同催化活性。对这两种纳米复合材料的比较研究表明，Ni-PD-Au在催化活性方面表现出色，但Ni-G-PD-Au具有显著的稳定性，在17次重复循环中效率约为100%。然而，除了优异的协同性能外，这两种纳米复合材料都表现出高磁化强度和高达350°C的热稳定性，分别确定了它们易于分离和在高温应用中的可持续性。
