Designing Nanoparticles and Nanoalloys for Gas-Phase Catalysis with Controlled Surface Reactivity Using Colloidal Synthesis and Atomic Layer Deposition

Abstract

Supported nanoparticles are commonly applied in heterogeneous catalysis. The catalytic performance of these solid catalysts is, for a given support, dependent on the nanoparticle size, shape, and composition, thus necessitating synthesis techniques that allow for preparing these materials with fine control over those properties. Such control can be exploited to deconvolute their effects on the catalyst’s performance, which is the basis for knowledge-driven catalyst design. In this regard, bottom-up synthesis procedures based on colloidal chemistry or atomic layer deposition (ALD) have proven successful in achieving the desired level of control for a variety of fundamental studies. This review aims to give an account of recent progress made in the two aforementioned synthesis techniques for the application of controlled catalytic materials in gas-phase catalysis. For each technique, the focus goes to mono- and bimetallic materials, as well as to recent efforts in enhancing their performance by embedding colloidal templates in porous oxide phases or by the deposition of oxide overlayers via ALD. As a recent extension to the latter, the concept of area-selective ALD for advanced atomic-scale catalyst design is discussed.

Does CO2 Oxidize Ni Catalysts? A Quick X-ray Absorption Spectroscopy Answer

“…MgAl 2 O 4 was synthesized via a coprecipitation method . Ni/MgAl 2 O 4 with 10 wt % nominal Ni loading was prepared by colloidal synthesis, based on the work of Vrijburg et al This method was chosen as it yields monodisperse NP size distributions, limiting the size-dependent spread on the results (Figure S1). In addition, Ni/MgAl 2 O 4 materials with targeted 5, 10, 20, and 40 wt % Ni were prepared via a “conventional” wet impregnation (WI) route for comparison.…”

“…However, since Ni-based catalysts typically consist of supported Ni nanoparticles (NPs), finite size effects 15 and metal−support interactions 16 chemical stability, 29 and the high activity reported for Ni/ MgAl 2 O 4 in CO 2 utilization. 34 This method was chosen as it yields monodisperse NP size distributions, limiting the size-dependent spread on the results 35 (Figure S1). In addition, Ni/MgAl 2 O 4 materials with targeted 5, 10, 20, and 40 wt % Ni were prepared via a "conventional" wet impregnation (WI) route for comparison.…”

Dual-Element Modulation Excitation XAS to Probe the Redox Surface Chemistry of a Ni–Fe Dry Reforming Catalyst

“…For the purpose of mitigating the size-dependent spread of the envisioned MEXAS results, 33 monodisperse Ni nanoparticles were synthesized, using a colloidal synthesis method, and deposited onto the support materials according to the procedure of De Coster et al 18 In a typical deposition step, the synthesized Ni NPs were washed three times using acetone (analytical reagent, 99.5+%, Chem-Lab Analytical) and nhexane (PESTINORM Supra Trace, ≥99%; VWR Chemicals) as the nonsolvent and solvent, respectively. The washed NPs, re-dispersed in 5 mL of n-hexane, were impregnated onto the supports.…”

Innovative approach to controlled Pt–Rh bimetallic nanoparticle synthesis

“…Achieving control of nanoparticle characteristics such as nanoparticle size, nanoparticle size distribution, and morphology during synthesis is a huge topic in itself. 17 The production of bimetallic nanoparticles with predetermined element distributions such as core–shell or solid solution further increases the complexity of the synthesis procedure. In the literature, two main approaches are utilized to produce nanoparticles; the heat-up and the hot-injection methods.…”