Simultaneously Constructing Active Sites and Regulating Mn–O Strength of Ru‐Substituted Perovskite for Efficient Oxidation and Hydrolysis Oxidation of Chlorobenzene

Abstract

Chlorinated volatile organic compounds (CVOCs) are a class of hazardous pollutants that severely threaten environmental safety and human health. Although the catalytic oxidation technique for CVOCs elimination is effective, enhancing the catalytic efficiency and simultaneously inhibiting the production of organic byproducts is still of great challenge. Herein, Ru‐substituted LaMn(Ru)O 3+ δ perovskite with Ru–O–Mn structure and weakened Mn–O bond strength has been developed for catalytic oxidation of chlorobenzene (CB). The formed Ru–O–Mn structure serves as favorable sites for CB adsorption and activation, while the weakening of Mn–O bond strength facilitates the formation of active oxygen species and improves oxygen mobility and catalyst reducibility. Therefore, LaMn(Ru)O 3+ δ exhibits superior low‐temperature activity with the temperature of 90% CB conversion decreasing by over 90 °C compared with pristine perovskite, and the deep oxidation of chlorinated byproducts produced in low temperature is also accelerated. Furthermore, the introduction of water vapor into reaction system triggers the process of hydrolysis oxidation that promotes CB destruction and inhibits the generation of chlorinated byproducts, due to the higher‐activity *OOH species generated from the dissociated H 2 O reacting with adsorbed oxygen. This work can provide a unique, high‐efficiency, and facile strategy for CVOCs degradation and environmental improvement.

Formaldehyde Ambient-Temperature Decomposition over Pd/Mn3O4–MnO Driven by Active Sites’ Self-Tandem Catalysis

“…This observation is further supported by the lowest force constant ( k ) value for Mn–O bonds in Pd/Mn 3 O 4 –MnO-1 (Figures S21 and S22). The weaker Mn–O bond results in increased oxygen vacancy ( O v ) formation, which is consistent with the findings from EPR tests (Figure S23). The presence of O v typically enhances both the mobility and reactivity of oxygen …”

“…Surface oxygen was characterized by XPS. The O 1s spectra (Figure b) are deconvoluted into three distinct peaks, corresponding to the lattice oxygen ( O latt ), surface-adsorbed oxygen ( O ads ), and physi/chemisorbed water ( O OH ), respectively. , Generally, O ads exhibits high electron density and is more prone to react with organic molecules, displaying enhanced activity in the oxidation of VOCs . However, no significant difference is observed in the proportions of O ads on Pd/Mn 3 O 4 –MnO-1, Pd/MnO, and Pd/Mn 3 O 4 .…”

Constructing Active Cu2+–O–Fe3+ Sites at the CuO–Fe3O4 Interface to Promote Activation of Surface Lattice Oxygen

“…Magnetite (Fe 3 O 4 ) is an earth-abundant TM oxide with an inverse spinel structure (Fe A 3+ (Fe 2+ Fe 3+ ) B O 4 ), in which electrons quickly transfer between Fe 2+ and Fe 3+ on the octahedral sites (B sites), endowing it a potential catalyst with good electrical conductivity. , However, this iron oxide exhibits low activity toward VOCs oxidation owing to its insufficient low-temperature reducibility and surface oxygen species . Numerous studies have demonstrated that regulating the metal–oxygen bond strength can boost the catalytic performance by enhancing the reactivity of surface lattice oxygen (O latt ), − which is crucial for VOCs degradation based on the Mars-van Krevelen (MvK) mechanism. For example, Zhang et al discovered that the oxidation activity of toluene could be improved by engineering the Co–O bond strength in Co 3 O 4 catalysts due to the increased amount of reactive oxygen species .…”

“…For example, the strength of the Mn 3+ –O bond was weakened owing to the formation of Cu 2+ –O–Mn 4+ , which boosted the redox and oxygen activation capabilities of the catalysts . The fabrication of the Ru–O–Mn structure over Ru-substituted perovskite creates active sites and regulates the Mn–O strength simultaneously, thereby exhibiting excellent catalytic activity for chlorobenzene conversion . Moreover, the Cu–O–Ti hybridization structure in the Cu 1 /TiO 2 catalyst promoted the adsorption and activation of molecular O 2 and triggered lattice distortion for activating surface O latt …”

“…3 The fabrication of the Ru−O−Mn structure over Ru-substituted perovskite creates active sites and regulates the Mn−O strength simultaneously, thereby exhibiting excellent catalytic activity for chlorobenzene conversion. 15 Moreover, the Cu−O−Ti hybridization structure in the Cu 1 /TiO 2 catalyst promoted the adsorption and activation of molecular O 2 and triggered lattice distortion for activating surface O latt . 22 To the best of our knowledge, few studies have been devoted to regulating the B-site Fe−O bond strength in antispinel structures to promote VOCs oxidation.…”