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Studying the relationship between electronic structure and activity helps to understand the catalytic mechanism since the catalytic combustion is a redox reaction dominated by electron transfer. Herein, we regulated the electron energy and O p-band center of La-based perovskite catalysts by a facile method of changing the B-site ion (B = Co, Mn, Fe). The crystal structure, morphology, reducibility, element valence distribution, and catalytic properties of prepared catalysts were characterized. Combining with DFT calculation, it was found that the low electron energy in (110) facets of LaCoO3/SiO2 catalyst contributes to the formation of reactive oxygen species and high-valence Co3+ ions. The highest oxygen adsorption activation capacity of LaCoO3/SiO2 originates from a moderate location of the O p-band center with respect to the Fermi level. As expected, the LaCoO3/SiO2 sample shows higher n-butylamine oxidation activity than that of LaMnO3/SiO2 and LaFeO3/SiO2. This work provides different insights into understanding the activity of La-based perovskite catalysts for oxidation reactions. [ABSTRACT FROM AUTHOR]

Phenolic root exudates (PREs) secreted by wetland plants facilitate the accumulation of iron in the rhizosphere, potentially providing the essential active iron required for the generation of enzymes that degrade polycyclic aromatic hydrocarbon, thereby enhancing their biodegradation. However, the underlying mechanisms involved are yet to be elucidated. This study focuses on phenanthrene (PHE), a typical polycyclic aromatic hydrocarbon pollutant, utilizing representative PREs from wetland plants, including p-hydroxybenzoic, p-coumaric, caffeic, and ferulic acids. Using hydroponic experiments, 16S rRNA sequencing, and multiple characterization techniques, we aimed to elucidate the interaction mechanism between the accelerated degradation of PHE and the formation of rhizosphere biofilm/iron plaque influenced by PREs. Although all four types of PREs altered the biofilm composition and promoted the formation of iron plaque on the root surface, only caffeic acid, possessing a similar structure to the intermediate metabolite of PHE (catechol), could accelerate the PHE degradation rate. Caffeic acid, notable for its catechol structure, plays a significant role in enhancing PHE degradation through two main mechanisms: (a) it directly boosts PHE co-metabolism by fostering the growth of PHE-degrading bacteria, specifically Burkholderiaceae, and by facilitating the production of the key metabolic enzyme catechol 1,2-dioxygenase (C12O) and (b) it indirectly supports PHE biodegradation by promoting iron plaque formation on root surfaces, thereby enriching free iron for efficient microbial synthesis of C12O, a crucial factor in PHE decomposition. [ABSTRACT FROM AUTHOR]

The development of transition metal oxide cathodes with high capacity and ultralong lifespan is one of the keys to promoting the performance of aqueous zinc–ion batteries, but it remains a crucial challenge. Herein, cobalt oxide is applied as an example to demonstrate that low‐degree fluorination is a novel approach to synergistically boost charge storage kinetics and stability. Specifically, partial substitution of O2− with F− intensifies electron delocalization of Co 3d orbitals, which reduces bulk charge transfer impedance and endows surface active sites with higher reactivity, thus achieving boosted redox kinetics and energy density. Moreover, the modification of coordination structure with the highest‐electronegativity F− can effectively inhibit irreversible phase transition and structural deformation, which assures significantly optimized cycling stability. As a result, the fluorinated Co3O4 demonstrates a distinctly improved specific capacity of 406 mAh g−1 at 1 A g−1, approximately a threefold increase compared to one of pristine Co3O4 (131 mAh g−1). The assembled fluorinated Co3O4//Zn battery delivers an ultrahigh energy density of 658 Wh kg−1 at 3.5 kW kg−1 and 95.7% capacity retention after 10 000 cycles. This work offers a new understanding of the electronic engineering of metal oxides toward high‐performance energy storage applications. [ABSTRACT FROM AUTHOR]

Edge structures, thiophene adsorption and hydrodesulfurization (HDS) mechanisms are investigated on the S-edge of triangular MoS2 nanoclusters using density functional theory. The calculated formation energies for different S coverages on the S-edge suggest that the formation of coordinative unsaturated site at the vertex and edge-I (close to the vertex) sites is preferred over the edge-II (away from the vertex) sites. The adsorption of thiophene on the top site of Mo atom mainly occurs at the edge-I, whereas bridge adsorption occurs at the edge-II. The 92% and 50% S-edge coverages involve relatively larger adsorption energies (− 0.68 and − 0.79 eV) among all the possible adsorption configurations. On the S edge with 92% S coverage, the hydrogenation route is more favorable, producing 1-butene. On the S edge with 50% S coverage, the direct desulfurization route is preferred, yielding butadiene. These findings deepen the understanding of edge structures of MoS2 nanoclusters and the corresponding HDS mechanisms for MoS2-based HDS catalysts. [ABSTRACT FROM AUTHOR]