Bingzhen Zhang

Selective aerobic oxidation of aromatic alcohols is pivotal in valorization. However, current catalysts suffer from low aldehyde selectivity, which severely restricts their scalable application and sustainable utilization. High-entropy oxides (HEOs), endowed with flexible electronic structures and tunable defect chemistry, offer promising opportunities to surmount these limitations. However, the structure-activity relationships governing the selective conversion of alcohols-derived substrates remain poorly elucidated. Herein, we design a defect-rich spinel-type high-entropy oxide (HE-NiFe₂O₄) via a solvent-free mechanochemistry synthesis route, and demonstrate its high catalytic efficiency and excellent aldehyde selectivity in the solvent-free aerobic oxidation of benzyl alcohol-a typical representative of lignin-derived aromatic alcohols-as well as a series of alcohols -related substrates. Mechanistic investigations reveal a trisynergistic catalytic ensemble consisting of oxygen vacancies (O_v), electron-rich Mn sites and electron-deficient Fe sites; this active system cooperatively lowers the activation barriers for O-H and C-H bond cleavage and facilitates the preferential activation of O₂. As a result, HE-NiFe₂O₄ achieves an ultrahigh turnover frequency (TOF ≈ 7224 h^-1), nearly quantitative aldehyde selectivity, and remarkable recyclability over multiple catalytic cycles under solvent-free and base-free conditions. This work highlights a defect-driven active site design strategy for sustainable catalytic upgrading of forest-derived bioresources to high-value bioproducts.

Hollow spherical structures can endow metal-organic framework (MOF) materials with new capabilities. However, devising an uncomplicated synthesis method for hollow MOF spheres remains a formidable challenge. Here, the green hydrothermal method is employed to drive the polymer template, inducing a thermal transition (viscous flow state) that facilitates escape and enables the construction of a series of hollow MOF spheres. The hollow MIL-101(Cr) spherical capsules (Void@MIL-101) with high stability and well-defined morphology are synthesized as the first example. After encapsulating Pd nanoparticles, it exhibits an accelerated mass transfer effect and superior catalytic selectivity in synthesizing secondary aromatic amines. Furthermore, the versatility of this in situ template-escape strategy is demonstrated through the successful construction of hollow CPM-243(Cr) and SiO₂ spheres. This innovative approach opens new avenues for the development of various hollow materials with enhanced properties.

While noble metal nanoparticles (MNPs) exhibit remarkable performance in heterogeneous catalysis and their incorporation into crystalline materials can fully exploit the combined advantages of both, achieving introduction of nanoclusters during material crystallization, precisely controlling their interactions, and facilitating catalyst recovery remain significant challenges. In this study, Au NPs, Pt NPs, and Pd NPs are supported on magnetic Fe₃O₄, enabling the modulation of the electronic states of MNPs by adjusting the introduction method. Notably, the catalysts (Pt/Fe₃O₄, Au/Fe₃O₄, and Pd/Fe₃O₄) demonstrate excellent activity in chemoselective reactions: cinnamaldehyde (CAL) hydrogenation (turnover number: 20,135 h^-1), nitrobenzene hydrogenation (with 99.9% selectivity for major nitrobenzene derivatives and robust stability at 19 cycles), and 3-nitrophenylacetylene (3-NPA) hydrogenation (yielding up to 98.4% 3-aminophenylacetylene (3-APA)), in stark contrast to the low activity of comparable catalysts. This paper proposes a novel and versatile solid-phase mechanochemistry strategy that achieves precise control over the microenvironment of MNPs while maintaining their inherent activity, thereby offering an effective approach to develop catalysts with high specificity and easy recovery capabilities.

Mixed-matrix membrane (MMM) reactors incorporating metal-organic framework (MOF) fillers have significant applications in fields such as separation, catalysis, and chiral resolution. However, the traditional method of directly mixing MOF fillers with polymers results in a symmetric structure where most of the MOF fillers are uniformly distributed across the membrane reactor's cross-section. During usage, this leads to a pronounced trade-off between flux and efficiency and the waste of the MOF, as the rich pore characteristics and active sites of MOFs are not fully utilized. In this study, we propose a liquid-phase ion activation strategy that enables the in situ formation of a uniform and densely packed MOF shell layer on the membrane surface during the phase inversion process of MMM fabrication. This asymmetric density distribution of the MOF-based MMM reactor selectively induces the generation of considerable nonradical ¹O₂ in the peroxomonosulfate (PMS) system, demonstrating superior catalytic degradation performance against antibiotics like TC and dye molecules (with a flux of 1880 L m^-2 h^-1 and a K_app value of 648 min^-1), as well as outstanding cycling stability and environmental tolerance. This discovery sheds light on the design and engineering of composite membrane materials and applications for advanced oxidation processes in water purification.

A critical constraint impeding the utilization of Mn-based oxide catalysts in NH3 selective catalytic reduction (NH3-SCR) is their inadequate resistance to water and sulfur. This vulnerability primarily arises from the propensity of SO2 to bind to the acidic site in manganese oxide, resulting in the formation of metal sulfate and leading to the irreversible deactivation of the catalyst. Therefore, gaining a comprehensive understanding of the detrimental impact of SO2 on the acidic sites and elucidating the underlying mechanism of this toxicity are of paramount importance for the effective application of Mn-based catalysts in NH3-SCR. Herein, we strategically modulate the acidity of the manganese oxide catalyst surface through the incorporation of Ce and Nb. Comprehensive analyses, including thermogravimetry, NH3 temperature-programmed desorption, in situ diffused reflectance infrared Fourier transform spectroscopy, and density functional theory calculations, reveal that SO2 exhibits a propensity for adsorption at strongly acidic sites. This mechanistic understanding underscores the pivotal role of surface acidity in governing the sulfur resistance of manganese oxide.

High-entropy oxides (HEOs) exhibit abundant structural diversity due to cationic and anionic sublattices with independence, rendering them superior in catalytic applications compared to monometallic oxides. Nevertheless, the conventional high-temperature calcination approach undermines the porosity and reduces the exposure of active sites (such as oxygen vacancies, OVs) in HEOs, leading to diminished catalytic efficiency. Herein, we fabricate a series of HEOs with a large surface area utilizing a microenvironment modulation strategy (m-NiMgCuZnCo: 86 m²/g, m-MnCuCoNiFe: 67 m²/g, and m-FeCrCoNiMn: 54 m²/g). The enhanced porosity in m-NiMgCuZnCo facilitates the presentation of numerous OVs, exhibiting an exceptional catalytic performance. This tactic creates inspiration for designing HEOs with rich porosity and active species with vast potential applications.