Metal species with different size (single atoms, nanoclusters, and nanoparticles) show different catalytic behavior for various heterogeneous catalytic reactions. It has been shown in the literature that many factors including the particle size, shape, chemical composition, metal–support interaction, and metal–reactant/solvent interaction can have significant influences on the catalytic properties of metal catalysts. The recent developments of well-controlled synthesis methodologies and advanced characterization tools allow one to correlate the relationships at the molecular level. In this Review, the electronic and geometric structures of single atoms, nanoclusters, and nanoparticles will be discussed. Furthermore, we will summarize the catalytic applications of single atoms, nanoclusters, and nanoparticles for different types of reactions, including CO oxidation, selective oxidation, selective hydrogenation, organic reactions, electrocatalytic, and photocatalytic reactions. We will compare the results o...

Metal Catalysts for Heterogeneous Catalysis: From Single Atoms to Nanoclusters and Nanoparticles.

It is well known that urbanization and industrialization have resulted in the rapidly increasing emissions of volatile organic compounds (VOCs), which are a major contributor to the formation of secondary pollutants (e.g., tropospheric ozone, PAN (peroxyacetyl nitrate), and secondary organic aerosols) and photochemical smog. The emission of these pollutants has led to a large decline in air quality in numerous regions around the world, which has ultimately led to concerns regarding their impact on human health and general well-being. Catalytic oxidation is regarded as one of the most promising strategies for VOC removal from industrial waste streams. This Review systematically documents the progresses and developments made in the understanding and design of heterogeneous catalysts for VOC oxidation over the past two decades. It addresses in detail how catalytic performance is often drastically affected by the pollutant sources and reaction conditions. It also highlights the primary routes for catalyst deactivation and discusses protocols for their subsequent reactivation. Kinetic models and proposed oxidation mechanisms for representative VOCs are also provided. Typical catalytic reactors and oxidizers for industrial VOC destruction are further discussed. We believe that this Review will provide a great foundation and reference point for future design and development in this field.

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Recent Advances in the Catalytic Oxidation of Volatile Organic Compounds: A Review Based on Pollutant Sorts and Sources.

The use of well-defined materials in heterogeneous catalysis will open up numerous new opportunities for the development of advanced catalysts to address the global challenges in energy and the environment. This review surveys the roles of nanoparticles and isolated single atom sites in catalytic reactions. In the second section, the effects of size, shape, and metal-support interactions are discussed for nanostructured catalysts. Case studies are summarized to illustrate the dynamics of structure evolution of well-defined nanoparticles under certain reaction conditions. In the third section, we review the syntheses and catalytic applications of isolated single atomic sites anchored on different types of supports. In the final part, we conclude by highlighting the challenges and opportunities of well-defined materials for catalyst development and gaining a fundamental understanding of their active sites.

Well-Defined Materials for Heterogeneous Catalysis: From Nanoparticles to Isolated Single-Atom Sites.

Low temperature catalytic oxidation of volatile organic compounds: a review

2D-Co 3 O 4 and 3D-Co 3 O 4 catalysts were prepared by the hard template method, and nano-Co 3 O 4 was synthesized by precipitation method. The catalytic activity for the oxidation of formaldehyde over various types of catalysts was investigated. The 3D-Co 3 O 4 catalyst attained a 100% conversion rate of formaldehyde at 130 °C with a space velocity of 30,000 mL/(g h), while the 2D-Co 3 O 4 catalyst oxidized formaldehyde completely at 150 °C in the same space velocity conditions. The difference in activity is due to the clear channel structure of the mesoporous Co 3 O 4 prepared by the hard template method, which has large specific surface area and surface active species that allows the reactant to diffuse and undergo surface reactions. The 3D-Co 3 O 4 had the best performance of formaldehyde oxidation due to the three-dimensional porous channel structure, larger specific surface area, abundant active surface oxygen species and active Co 3+ cationic species on the exposed (2 2 0) crystal face. Complete conversion of formaldehyde had remained the same after 3D-Co 3 O 4 was observed for 160 h. Therefore, the 3D-Co 3 O 4 catalyst has the best catalytic activity and stability for formaldehyde, which might be a non-noble catalyst for catalytic removal of formaldehyde in practical application.

Comparison of the performance for oxidation of formaldehyde on nano-Co3O4, 2D-Co3O4, and 3D-Co3O4 catalysts

Complete oxidation of formaldehyde at ambient temperature over supported Pt/Fe2O3 catalysts prepared by colloid-deposition method

Catalytic oxidation of formaldehyde over different silica supported platinum catalysts

Adsorption behaviors of methyl orange dye on nitrogen-doped mesoporous carbon materials.

Catalytic oxidation of formaldehyde over Pt/Fe2O3 catalysts prepared by different method

Three supported Pt/Fe2O3 catalysts were prepared by depositing platinum colloids with discrete particle sizes onto the surface of Fe(OH)3 powders, which were then calcined at an elevated temperature. Pt nanoparticle colloids with mean diameters of 1.1, 1.9, or 2.7 nm were synthesized in order to investigate the effects of particle size on the structure and CO oxidation properties of these Pt/Fe2O3 catalysts. All Pt/Fe2O3 catalysts demonstrated activity in low-temperature CO oxidation, with the sample containing Pt nanoparticles with a mean diameter of 1.9 nm (designated Pt/Fe2O3-b) exhibiting relatively higher catalytic activity. Compared with the other two catalysts, Pt/Fe2O3-b exhibited an increased ability to activate oxygen and maintain the stability of Pt species, correlating with its higher catalytic activity. The results of various characterization techniques revealed that the mean particle size of the Pt nanoparticles could influence the chemical states of Pt species and the strength of metal–supp...

Nihong An

Papers

Complete oxidation of formaldehyde at ambient temperature over supported Pt/Fe2O3 catalysts prepared by colloid-deposition method

Catalytic oxidation of formaldehyde over different silica supported platinum catalysts

Adsorption behaviors of methyl orange dye on nitrogen-doped mesoporous carbon materials.

Catalytic oxidation of formaldehyde over Pt/Fe2O3 catalysts prepared by different method

Size Effects of Platinum Colloid Particles on the Structure and CO Oxidation Properties of Supported Pt/Fe2O3 Catalysts