Pt-Modulated CuMnO_x Nanosheets as Catalysts for Toluene Oxidation

Abstract

Controllable ternary Pt–Cu–Mn lamellar oxides with different amounts of Pt were synthesized using a facile and expeditious self-propagating flaming technique for catalytic oxidation of toluene. The surface structure, composition, and structure–performance relationship were investigated by combining X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) surface area, scanning electron microscopy (SEM), transmission electron microscopy (TEM), hydrogen temperature-programmed reduction (H2-TPR), and X-ray photoelectron spectroscopy (XPS). The catalytic performance of the as-produced catalysts toward the catalytic oxidation of toluene was investigated. Among the catalysts, the 0.5Pt-MnCu catalyst has shown 90% toluene removal at 228 °C with excellent cyclic stability, which is a significant achievement for MnCu binary nanosheet-like catalysts containing low amounts of Pt (0.5 wt %). This study has also inferred the degradation activity of modulated MnCu composite catalysts, which greatly hinges on the doping level of Pt. The lattice oxygen species are dominating according to the Mn–O bond strength, local environment, and reducibility. Moreover, Pt can increase the covalency of surface metal–oxygen bonds and electron affinity of surface metal-coordinated oxygen centers, thereby expediting the adsorption/activation of the gaseous oxygen molecules on oxide surfaces, which can step up the lattice oxygen as well as oxygen vacancy-involved reactions to invoke the Mars–van Krevelen and Langmuir–Hinshelwood mechanisms for boosting the overall toluene oxidation performance of PtCuMnO x catalytic materials. Based on the obtained results, this study proposes a vital insight into manipulating the nanoscale catalytic functions, which could also promise pivotal potential toward engineering the state-of-the-art transition-metal nanostructure for environmental catalysis.

Optimized Synthesis Routes of MnOx-ZrO2 Hybrid Catalysts for Improved Toluene Combustion

“…It was widely accepted that the physical and chemical properties, such as component of active phase, specific surface area, Mn valence, concentration of adsorbed oxygen/lattice oxygen and reduction ability, can command the activity of the catalyst [48]. For the component factor of the active phase, we found that the ratio of Mn/Zr and their synthesis routes play a vital role in adjusting the content of active centers, and a low molar ratio (<2/3) of Mn/Zr would lead to the formation of a solid solution of Mn x Zr 1−x O 2 .…”

Catalytic Oxidation of Toluene over Fe-Rich Palygorskite Supported Manganese Oxide: Characterization and Performance

“…It is well known that the catalytic activity of the Mn oxide catalysts is affected by their physical and chemical properties, such as the active component, specific surface area, the valence state of Mn, and the surface adsorbed oxygen or lattice oxygen concentration [7]. In this work, the x%Mn-Pal catalysts were successfully obtained.…”

“…Up to date, researchers have developed a variety of catalysts for the removal of VOCs, mainly including precious metal materials [6,7] and transition-metal oxides [8,9]. Although the noble metal catalysts display excellent properties, the problems of high cost, easy sintering, and poisoning have not been effectively solved, which limit their further practical applications [10].…”

Co2Cu1CeyOx Mixed Metal Oxide Nanoparticles with Oxygen Vacancies as Catalysts for Toluene Oxidation

“…A major part of such studies has been committed to the exploration of transition metals (Mn, Fe, Co, Ni, and Cu) oxides and rare earth metal (La and Ce) oxides. 5,6 Of these oxides, the catalysts formed by Co 3 O 4 , or CuO and CeO 2 , were shown to exhibit excellent catalytic activities for toluene oxidation. 7,8 Surface oxygen vacancies have received wide attention, which is due to their key roles in heterogeneous catalytic reactions.…”

“…In recent years, many studies have, therefore, been performed with a focus on the replacement of precious metals by the design and syntheses of catalysts containing nonprecious metal oxides. A major part of such studies has been committed to the exploration of transition metals (Mn, Fe, Co, Ni, and Cu) oxides and rare earth metal (La and Ce) oxides. , Of these oxides, the catalysts formed by Co 3 O 4 , or CuO and CeO 2 , were shown to exhibit excellent catalytic activities for toluene oxidation. , …”