Impact of Ceria Support Morphology on Au Single‐Atom Catalysts for Benzyl Alcohol Selective Oxidation

Abstract

Alcohol oxidations are a key industrial chemical transformation, with aldehydes and ketones finding use in an array of applications. Nobel metals are known for their activity towards this chemoselective transformation, however, sustainable catalyst synthesis requires optimal utilisation of these scarce elements. Here, we report Au catalytic systems based on the deposition of isolated Au sites on different morphologies of ceria in which different surface facets of the support are exposed. Through tailoring the support morphology and from extensive catalyst characterisation, it is shown that the exposed facet is critical for controlling the formation (or not) of isolated Au sites. Both the 110 and 111 facets are capable of this feat, yielding single‐atom sites for rod, octahedron, and polyhedron morphologies. In contrast, the 100 facet is not, resulting in Au nanoparticles on cubic ceria. This dictation over Au species is critical to benzyl alcohol oxidation capacity at mild conditions and in the absence of a soluble base, with only single‐atom catalyst (SAC) systems demonstrating activity. Furthermore, the exposed surface facet also governs the degree of surface oxygen vacancies, which is critical to catalyst activity and arises from its control over substrate adsorption strength, as revealed through T1/T2 NMR relaxation measurements.

Ceria Nanoparticles on Modified MXene for Aerobic Oxidation of 4-Methoxybenzyl Alcohol

“…A notable innovation in this green approach involves using molecular oxygen (O 2 ) as the oxidant. − This method is particularly commendable not only because oxygen is plentiful and inexpensive but also because it mainly produces water as a byproduct, thus reducing the hazardous waste associated with conventional oxidation processes. The pursuit of sustainable methods has led to the development of numerous new techniques for converting benzyl alcohols to benzaldehydes, frequently using catalysts that contain precious metals such as Rh, Pd, Pt, Ru, and Au. − However, the scarcity and high cost of these metals are barriers to their widespread commercial use. In recent years, there has been significant research into catalysts made from more available and affordable non-noble metals such as Cu, Ni, V, Mo, Fe, and Zr, − aimed at promoting the aerobic oxidation of alcohols while ensuring economic and environmental sustainability.…”