Deep Understanding of Strong Metal Interface Confinement: A Journey of Pd/FeO_x Catalysts

Abstract

Tuning the atomic interface configuration of noble metals (NMs) and transition-metal oxides is an effective straightforward yet challenging strategy to modulate the activity and stability of heterogeneous catalysts. Herein, Pd supported on mesoporous Fe2O3 with a high specific surface area was rationally designed and chosen to construct the Pd/iron oxide interface. As a versatile model, the physicochemical environments of Pd nanoparticles (NPs) could be precisely controlled by taming the reduction temperature. The experimental and density functional theory calculation results unveiled that the catalyst in the support–metal interface confinement (SMIC) state showed significantly enhanced catalytic activity and sintering resistance for CO oxidation. The constructed Fe sites at the interfaces between FeO x overlayers and Pd NPs not only provided additional coordinative unsaturated ferrous sites for the adsorption and activation of O2, thereby facilitating the activation efficiency of O2, but also impressively changed the reaction pathway of CO oxidation. As a result, the catalyst followed the Pd/Fe dual-site mechanism instead of the classical Mars–van Krevelen mechanism. For the catalyst in the strong metal–support interaction (SMSI) state, its catalytic activity was seriously suppressed because of the excessive encapsulation of the active Pd sites by FeO x overlayers. The present study therefore provides detailed insights into the SMIC and SMSI in ferric oxide-supported Pd catalysts, which could guide the preparation of highly efficient supported catalysts for practical applications.

High‐performance adsorptive desulfurization by ternary hybrid boron carbon nitride aerogel

“…The pore volumes of all the samples were calculated by the BJH method using the Halsey equation with Faas correction. As shown in Figure 5, the isotherms consist of a hybrid of type I and type IV curves with an H3 hysteresis loop according to the IUPAC classification, which demonstrates the presence of micropore and mesoporous structures in BCN aerogels 24,47,50,54 . It is worth noting that the specific surface area (1220 m 2 g −1 ) of BCN‐2.5 is 2.5 times that of BCN‐1 (494 m 2 g −1 ) (Table S3).…”

Facile Construction of Carbon Encapsulated of Earth‐Abundant Metal Sulfides for Oxygen Electrocatalysis

“…The Co 2p 3/2 or Co 2p 1/2 spectra are constituted by three peaks, which are assigned to Co 2+ , Co 3+ , and satellite, respectively (Figure S1) [21] . Notably, the Co 2+ peak of Co−S‐700 shifts toward higher binding energy, which signifies the rise of the valence state for Co and the presence of electron transfer between different sulfides [21,22] . This strong interaction is in favor of the reaction kinetics for the OER and ORR.…”

Low–Medium Temperature-Selective Catalytic Reduction of NO with NH3 over a Mn/Co-MOF-74 Catalyst

“…As one of the main pollutants released by the burning of fossil fuels, nitrogen oxide (NO) is the main target of flue gas treatment in coal-fired power plants. If its emissions cannot be effectively controlled, it will exacerbate a series of air pollution problems such as acid rain and photochemical smog, 1 − 5 thereby threatening the ecosystem and human health. By now, NH 3 -selective catalytic reduction (NH 3 -SCR) is not only the most widely used NO X control technology in coal-fired power plants but also in other industries such as glass, steel, cement, and so forth.…”