Enhancement of Cs on Co₃O₄ for N₂O Catalytic Decomposition: N₂O Activation and O₂ Desorption

Abstract

In this work, a series of cesium (Cs) modified metal oxide (Co3O4, CuO, Mn2O3, and NiO) catalysts were synthesized and investigated for N2O catalytic decomposition. More than 95% N2O conversion was obtained with the Cs-supported Co3O4 (Cs/Co) catalyst at 300 °C, but only a slight increase or even suppression was obtained with the other catalysts. The activation energy (E a) varied significantly for Cs modified catalysts. It was found that both of N2O adsorption–dissociation (from N2O-TPD) and O2 desorption capacities (from O2-TPD) were highly correlated with the N2O decomposition activity. Highly optimized N2O activation and O2 desorption capacities contributed to the boosting performance of the Cs/Co catalyst. Moreover, the improved electron transfer property inferred from H2-temperature-programmed reduction and X-ray photoelectron spectroscopy was likely to facilitate the reaction processes and promote N2O catalytic decomposition performance.

Masked Reactivity of Hydrated Clusters of Monovalent Manganese Ions: Water Insertion versus Nitrous Oxide Activation–A Density Functional Theory Investigation

“…In short, according to our DFT results, the relative thermodynamic stability between 7 20 In the actual experimental setting, cluster ions generated prior to their encounter with N 2 O would have sizes of at least n = 20−30. These large-size clusters would have easily undergone the O−H insertion (given the small barrier of ∼40 kJ mol −1 for the oxidative addition of 5 [Mn I (H 2 O) n ] + clusters calculated for n = 11−12) and been trapped in the inserted Mn(III) form (given its large barrier of ∼60 kJ mol −1 for the reductive elimination for the same size range).…”

“…As a demonstrative example, the geometries and relative enthalpies of the lowest-energy structures at n = 8 were shown in Figure 1. They include the noninserted Mn(I) hydration clusters at the ground septet state 7 [Mn I (H 2 O) 8 ] + (Figure 1a) and the slightly higher-lying quintet state The metal core in these hydration clusters is tri-, tetra-, penta-, or hexacoordinated (3c, 4c, 5c, or 6c, respectively). Throughout this Article, the enthalpies at 0 K (ΔH 0 °in kJ mol −1 ) of all geometries at various spin states are relative to that of the global minimum of septet 7 [Mn I (H 2 O) n ] + of corresponding n, which is consistently the lowest-energy spin state of the noninserted clusters for all studied sizes (n = 1 − 12) (Figure S1).…”

“…They include the noninserted Mn(I) hydration clusters at the ground septet state 7 [Mn I (H 2 O) 8 ] + (Figure 1a) and the slightly higher-lying quintet state The metal core in these hydration clusters is tri-, tetra-, penta-, or hexacoordinated (3c, 4c, 5c, or 6c, respectively). Throughout this Article, the enthalpies at 0 K (ΔH 0 °in kJ mol −1 ) of all geometries at various spin states are relative to that of the global minimum of septet 7 [Mn I (H 2 O) n ] + of corresponding n, which is consistently the lowest-energy spin state of the noninserted clusters for all studied sizes (n = 1 − 12) (Figure S1). Relative enthalpies of the lowest-lying conformers with different coordination numbers for 7 [Mn I (H 2 O) 2 ] + for which the lowest-energy structure contains a dicoordination metal core (2c), which is 23 kJ mol −1 lower than in energy its 1c analogue for n = 2.…”

“…2 While second-or third-row transition metal-based catalysts have long being established with demonstrated excellent catalytic and activating capabilities for various reactions, there has recently been increasing interest in catalytic systems based on first-row transition metals, which are less toxic and more costeffective 3 as well as feature unique chemical properties 4 as compared with their heavier congeners. In the context of smallmolecule activation, examples include the activation of carbon dioxide by manganese pincer complexes 5 and carbon nanosheet-supported manganese single-atom catalysts, 6 the decomposition of nitrous oxide by cesium-supported Co 3 O 4 , 7 and water-splitting reaction by Mn-incorporated carbon nitride 8 and hydrated Mn(II) phosphate. 9 In studying the chemical behavior of transition metal systems, single-metal catalysts and gas-phase solvated transition metal ion clusters have been invoked as important prototypes to provide potential insights into the mechanisms and intrinsic roles of the transition metals in various chemical reactions and catalytic systems.…”

Kinetic Analysis of Consecutive/Parallel Transformation of Furfural to Biomass-Based Primary Amide by Using a “Concentration–Time” Integral

“…Co 3 O 4 has recently attracted much attention as a heterogeneous catalyst and catalyst support in various reactions such as CO oxidation, NO x reduction, and O 2 evolution . Moreover, doping or incorporation of various transition metals into the spinel structure of Co 3 O 4 further extends their catalytic application, which includes La 1– x Sr x CoO 3 , Mn x Co 3– x O 4 , Mn x Co 1– x Co 2 O 4 , Zn x Co 1– x Co 2 O 4 , and Co 3– x Fe x O 4 . Considering the fact that Cu complexes are important and efficient homogeneous catalysts for aldehyde amidation, ,− Cu-doped Co 3 O 4 (Cu/Co 3 O 4 ) with a mesoporous structure was well-developed as an efficient and recyclable nanocatalyst for the direct amidation of aldehyde in this research.…”