Trifunctional C@MnO Catalyst for Enhanced Stable Simultaneously Catalytic Removal of Formaldehyde and Ozone

Abstract

The key challenge for controlling low concentration volatile organic compounds (VOCs) is to develop technology capable of operating under mild conditions in a cost-effective manner. Meanwhile, ozone (O3) is another dangerous air pollutant and byproducts of many emerging air quality control technologies, such as plasma and electrostatic precipitators. To address these multiple challenges, we report here a design strategy capable of achieving the following trifunctions (i.e., efficiently VOCs adsorption enrichment, ozone destruction, and stable VOCs degradation) from the synergistic effect of adsorption center encapsulation and catalytic active sites optimization using 2D manganese­(II) monoxide nanosheets decorated carbon spheres with hierarchical core–shell structure. Carbonous residues in the as-synthesized MnO x matrices played a key role for in situ generating homogeneous dispersed unsaturated MnO during the annealing of the as-synthesized C@MnO x in the flow of argon under a proper calcination temperature (550 °C). The formation of the intimacy interface between MnO and carbon not only facilitates the adsorption and subsequent catalytic reaction but also results in a gatekeeper effect on the protection of the carbon sphere against the etching of O3. Such a composite architecture achieved the highest stable removal efficiency (100% for 60 ppm of formaldehyde and 180 ppm of O3 simultaneously) and 100% CO2 selectivity under a GHSV of 60000 mL h–1 g–1. These findings thus open up a way to address current multiple challenges in air quality control using a single hierarchical core–shell structure.

Effect of Mn addition on the low‐temperature NH3‐selective catalytic reduction of NOx over Fe2O3/activated coke catalysts: Experiment and mechanism

“…As discussed above (Sections 3.1.3 and 3.1.4), the 8Mn6Fe/AC catalyst has the capacity to adsorb gaseous NH 3 and NO x on the catalyst surface. The gaseous NH 3 can be adsorbed and activated on the surface acid sites of the catalyst and then reacts with gaseous NO x or adsorbed NO x ; that is, both the Langmuir–Hinshelwood (L‐H) mechanism and Eley–Rideal (E‐R) mechanism may contribute to the NO x reduction over 8Mn6Fe/AC catalyst (shown in Figure ) …”

“…The gaseous NH 3 can be adsorbed and activated on the surface acid sites of the catalyst and then reacts with gaseous NO x or adsorbed NO x ; that is, both the Langmuir-Hinshelwood (L-H) mechanism and Eley-Rideal (E-R) mechanism may contribute to the NO x reduction over 8Mn6Fe/AC catalyst (shown in Figure 13). [55][56][57][58] The NO x reduction over 8Mn6Fe/AC catalyst via the L-H mechanism can be approximately explained by reactions (2)…”

One‐step synthesis of a WO3‐CuS nanosheet heterojunction with enhanced photocatalytic performance for methylene blue degradation and Cr(VI) reduction

“…The simultaneous scavenging of coexisting pollutants has attracted lots of attention, because the pollutants widely coexist in wastewater, soil and air . Experiments on simultaneous photocatalytic degradation of MB and Cr(VI) on the WO 3 ‐CuS composite also were carried out herein to investigate the interaction effect.…”

Manganese Oxide Modified Nickel Catalysts for Photothermal CO Hydrogenation to Light Olefins

“…It is speculated that electron transfer from MnO to the supported Ni 0 nanoparticles may be responsible for this phenomenon (i.e., formation of Ni δ− states). In the Mn K‐edge EXAFS spectra, coordination numbers about metal atoms correlate with shell intensities . In Figure S16c, Supporting Information, considerable variation was seen in the intensities of the Mn‐O and Mn‐Mn features on going from Ni‐400 to Ni‐600, which suggested significant variation in the coordination numbers of Mn atoms.…”