Control of Catalytic Activity of Nano‐Au through Tailoring the Fermi Level of Support

Abstract

Nanoparticles of noble metals dispersed on solid support have been extensively utilized for catalyzing chemical reactions for energy conversion, environmental remediation, and chemical industry for their remarkable catalytic performance. [1][2][3][4] To maneuver the catalytic performance of these materials, tremendous efforts have been focused on the control of metal nanoparticles, including size and shape, [5][6][7] composition, [8] and chemical ordering. [9] At the meantime, the influence of the support on catalytic properties maximizing the number of active sites accessible for reaction have been well recognized. For example, the size distribution [10] and structural stability [11] of metal nanoparticles could be adjusted via the selection of the support. Furthermore, encapsulation of the metals by support species under high temperature treatment are widely observed, which finally results in the establishment of the classical strong metal-support interaction (SMSI). [12] However, the physicochemical interaction between metal and support cannotThe catalytic properties of nanometals are strongly dependent on their electronic states which, are influenced by the interaction with the supports. However, a precise manipulation of the electronic interaction is lacking, and the nature of the interaction is still ambiguous. Herein, using Au/ZnFe x Co 2−x O 4 (x = 0-2) as a model system with continuously tuned Fermi levels of supports, the electronic structure of the Au catalyst can be precisely controlled by changing the Fermi level of the support, which arises from the charge redistribution between the two phases. A higher Fermi level of ZnFe 2 O 4 support makes nano-Au negatively charged and thus facilitates the oxidation of CO, and in contrast, a lower Fermi level of ZnCo 2 O 4 support makes nano-Au positively charged and is preferential to the oxidation of benzyl alcohol. This work represents a solid step towards exploration of advanced catalysts with deliberate design of electronic structure and catalytic properties.

A novel plasma reduction for the preparation of AuPd bimetallic nanocatalyst and its application in selective oxidation of benzyl alcohols

“…Supported gold (Au) and palladium (Pd) nanoparticles are promising catalyst for this reaction [5][6][7]. Strategies have been developed to optimize the activity and selectivity of nanocatalysts, including size and shape control of nanometals [8,9], engineering the supports [10], or composition adjustment [3]. In particular, bimetallic nanoparticles are attracting intensive interests because of the improved catalytic properties deriving from the synergetic effects between two elements.…”

“…differences in particle size, morphology, structure, and even electronic properties [13][14][15]. Currently, most work on noble metal nanocatalyst is accomplished by bottom-up synthesis in solutions that generally contains step of reduction [10,16] or decomposition [14,17] of positive valent metal precursors at harsh conditions. For example, the conventional method mainly involves impregnation that usually needs thermal reduction to obtain metallic nanoparticles.…”

Ni/NiO Nanocomposites with Rich Oxygen Vacancies as High-Performance Catalysts for Nitrophenol Hydrogenation

“…In this scenario, interactions with the oxide support significantly impact the electronic structures and in turn the catalytic performance of nanometals [21,22]. Recently, we have demonstrated that the electron exchange between the two phases is highly correlated with the Fermi level of the oxide support [23]. The electron density and Fermi level of oxides can be tailored by breaking the symmetry or stoichiometry of the crystal structure, such as defects engineering [24,25] or doping [26,27], resulting in changes in catalytic activity and activation energy of the catalysts.…”

Formation of a Pd/MgO Structured Catalyst for the Aqueous Oxidation of Silane to Silanol

“…In addition, it has been widely recognized that the support plays more roles than simply providing a surface area. Electronic interactions across the interface have a significant and direct impact on the catalytic activity of the metal nanocatalyst [4,5]. In this scenario, the quality of the metal-support interface is key in order to manipulate their performance even if the metal and the support are the same, as such an interaction can affect only the sites less than 1 nm away from the interface [4,6].…”

“…Electronic interactions across the interface have a significant and direct impact on the catalytic activity of the metal nanocatalyst [4,5]. In this scenario, the quality of the metal-support interface is key in order to manipulate their performance even if the metal and the support are the same, as such an interaction can affect only the sites less than 1 nm away from the interface [4,6]. However, metals are simply loaded on the support in most nanocatalysts prepared by conventional solution methods, limiting the metal-support interaction and weakening the metal stability in harsh conditions [7].…”