Weber Matthieu, Lamboux Cassandre, Navarra Bruno, Miele Philippe, Zanna Sandrine, Dufond Maxime E, Santinacci Lionel, Bechelany Mikhael
Institut Européen des Membranes, IEM, UMR-5635, Univ Montpellier, CNRS, ENSCM, 34095 Montpellier, France.
Institut Universitaire de France, 1 rue Descartes, 75231 Paris, France.
Nanomaterials (Basel). 2018 Oct 18;8(10):849. doi: 10.3390/nano8100849.
The ability to prepare controllable nanocatalysts is of great interest for many chemical industries. Atomic layer deposition (ALD) is a vapor phase technique enabling the synthesis of conformal thin films and nanoparticles (NPs) on high surface area supports and has become an attractive new route to tailor supported metallic NPs. Virtually all the studies reported, focused on Pd NPs deposited on carbon and oxide surfaces. It is, however, important to focus on emerging catalyst supports such as boron nitride materials, which apart from possessing high thermal and chemical stability, also hold great promises for nanocatalysis applications. Herein, the synthesis of Pd NPs on boron nitride (BN) film substrates is demonstrated entirely by ALD for the first time. X-ray photoelectron spectroscopy indicated that stoichiometric BN formed as the main phase, with a small amount of BNO, and that the Pd particles synthesized were metallic. Using extensive transmission electron microscopy analysis, we study the evolution of the highly dispersed NPs as a function of the number of ALD cycles, and the thermal stability of the ALD-prepared Pd/BN catalysts up to 750 °C. The growth and coalescence mechanisms observed are discussed and compared with Pd NPs grown on other surfaces. The results show that the nanostructures of the BN/Pd NPs were relatively stable up to 500 °C. Consequent merging has been observed when annealing the samples at 750 °C, as the NPs' average diameter increased from 8.3 ± 1.2 nm to 31 ± 4 nm. The results presented open up exciting new opportunities in the field of catalysis.
制备可控纳米催化剂的能力对许多化学工业来说极具吸引力。原子层沉积（ALD）是一种气相技术，能够在高比表面积载体上合成保形薄膜和纳米颗粒（NP），并且已成为定制负载型金属NP的一条有吸引力的新途径。几乎所有已报道的研究都集中在沉积在碳和氧化物表面的钯纳米颗粒上。然而，关注诸如氮化硼材料等新兴催化剂载体很重要，这类材料除了具有高热稳定性和化学稳定性外，在纳米催化应用方面也极具前景。在此，首次完全通过原子层沉积法在氮化硼（BN）薄膜基底上合成了钯纳米颗粒。X射线光电子能谱表明，化学计量比的BN形成为主相，伴有少量的BNO，并且合成的钯颗粒为金属态。通过广泛的透射电子显微镜分析，我们研究了高度分散的纳米颗粒随原子层沉积循环次数的演变，以及原子层沉积制备的钯/氮化硼催化剂在高达750℃时的热稳定性。讨论了观察到的生长和聚结机制，并与在其他表面生长的钯纳米颗粒进行了比较。结果表明，氮化硼/钯纳米颗粒的纳米结构在高达500℃时相对稳定。当在750℃对样品进行退火时，观察到了随后的合并现象，因为纳米颗粒的平均直径从8.3±1.2纳米增加到了31±4纳米。所呈现的结果为催化领域开辟了令人兴奋的新机遇。
