Winning Combination of Cu and Fe Oxide Clusters with an Alumina Support for Low-Temperature Catalytic Oxidation of Volatile Organic Compounds

Abstract

A γ-alumina support functionalized with transition metals is one of the most widely used industrial catalysts for the total oxidation of volatile organic compounds (VOCs) as air pollutants at higher temperatures (280–450 °C). By rational design of a bimetal CuFe-γ-alumina catalyst, synthesized from a dawsonite alumina precursor, the activity in total oxidation of toluene as a model VOC at a lower temperature (200–380 °C) is achieved. A fundamental understanding of the catalyst and the reaction mechanism is elucidated by advanced microscopic and spectroscopic characterizations as well as by temperature-programmed surface techniques. The nature of the metal–support bonding and the optimal abundance between Cu–O–Al and Fe–O–Al species in the catalysts leads to synergistic catalytic activity promoted by small amounts of iron (Fe/Al = 0.005). The change in the metal oxide–cluster alumina interface is related to the nature of the surfaces to which the Cu atoms attach. In the most active catalyst, the CuO6 octahedra are attached to 4 Al atoms, while in the less active catalyst, they are attached to only 3 Al atoms. The oxidation of toluene occurs via the Langmuir–Hinshelwood mechanism. The presented material introduces a prospective family of low-cost and scalable oxidation catalysts with superior efficiency at lower temperatures.

Synthesis of Helional by Hydrodechlorination Reaction in the Presence of Mono- and Bimetallic Catalysts Supported on Alumina

“…Parameters of the nearest coordination shells around Pd cations in the Pd/Al 2 O 3 and (Cu,Pd)/Al 2 O 3 catalyst measured in the initial state of the fresh catalysts and in the final state after catalytic reaction: average number of neighbor atoms (N), distance (R), and Debye-Waller factor (σ 2 ). References [14][15][16][17][18][19][20][21][22][23][24][25][26] are cited in the Supplementary Materials.…”

Materials Enabling Methane and Toluene Gas Treatment

“…Catalytic oxidation has been extensively studied as an efficient, resource-aware method of removing toluene from indoor air and industrial exhaust gases without additional treatment. Transition metal-functionalized γ-alumina carriers are widely used as industrial catalysts for the complete oxidation of volatile organic molecules at elevated temperatures, and Zumbar et al achieved full oxidation activity of toluene at lower temperatures (200-380 • C) by rationally designing bimetallic CuFe-γ-alumina catalysts [55].…”

Highly Active and Sintering-Resistant Pt Clusters Supported on FeOx–Hydroxyapatite Achieved by Tailoring Strong Metal–Support Interactions

“…However, the ability of isolated metal centers to enhance reactions that involve multiple reactant molecules, intermediates, and multistep redox processes is constrained by their geometric limitations. , Compared with SACs, cluster catalysts with tailored electronic structures and multiple adsorption sites offer an improved potential for catalytic complex reactions. The incorporation of heteroatoms in cluster catalysts can introduce adsorption sites with varied properties and donate or withdraw electrons to or from metal clusters to provide a valuable strategy for tuning reactivity patterns. − However, experimentally controlling the structures of clusters is highly challenging; hence, theoretical modeling and computational simulations frequently play a pivotal role in elucidating the structure–activity relationship . Moreover, a profound comprehension of the interaction between metal clusters and their support plays a crucial role in bridging the gap between SACs and metal nanoparticle catalysts.…”