Feng Zhang

Surface hydrophilicity and framework polar-group dynamics regulate proton transport in powder-compacted Ag-MOFs by governing intercrystallite water-mediated pathways and proton-migration activation barriers, respectively.

Electrocatalytic two-electron oxygen reduction reaction (2e--ORR) offers a green route for hydrogen peroxide (H2O2) synthesis, yet tailoring catalyst selectivity in complex environments like seawater remains a grand challenge. Herein, we report a composite of ZIF-67 and spherical graphite featuring a well-defined CoN2O3 coordination structure. This work elucidates a synergistic regulatory mechanism governed by N-to-O ligand exchange: the incorporation of high-electronegativity oxygen ligands, coupled with a reduced nitrogen coordination number, induces a significant downward shift of the cobalt d-band center. This electronic depletion not only optimizes the *OOH adsorption energy but, more critically, lowers the affinity of Co sites toward Cl-poisoning-a key challenge in seawater-based electrolysis. Theoretical and experimental analyses confirm that this electronic reconfiguration suppresses competitive Cl- adsorption and stabilizes the *OOH intermediate while preventing O-O bond cleavage. In simulated seawater (0.5 M NaCl), the catalyst delivers a H₂O₂ selectivity of ~71% within the 0-0.45 V vs. RHE potential range, exhibiting outstanding reaction kinetics (Tafel slope as low as 88.52 mV dec-1) and an exceptional high productivity (>230,000 mg gcat-1 h-1), approximately 4.5 times higher than leading neutral-media catalysts. Furthermore, it exhibits remarkable stability and tolerance to chloride poisoning for over 10 hours.

Understanding proton conduction at the microscopic level requires going beyond static crystallographic descriptions to capture the dynamic behavior of hydrogen-bonded networks. However, most existing techniques probe only limited or discrete frequency windows, preventing a continuous view of the molecular motions governing proton transport in solids. Herein, three praseodymium-based coordination polymers featuring distinct hexameric water clusters—{[Pr(pda)(H₂O)₄Ce(pda)₂(H₂pda)]·7H₂O}_n (Pr-Ce-H₂pda-H₂O, H₂pda = 2,6-pyridinedicarboxylic acid), {[Pr(pda)(Hpda)(H₂O)₂]·4H₂O}_n (Pr-Hpda-H₂O) and {[Pr₂(pda)₃(H₂O)₃]·H₂O}_n (Pr-pda-H₂O)—are employed as model systems to elucidate the relationship between hydrogen-bonded network dynamics and proton transport. By combining proton conductivity measurements with broadband dielectric spectroscopy, we establish a direct correlation between collective dielectric relaxation of water clusters and proton-transfer activation barriers within the same temperature range. The results reveal that proton conduction is governed by a critical kinetic balance between hydrogen-bond network rearrangement capability and pathway continuity. Moderately slow relaxation of hydrogen-bonded networks facilitates O–H bond reformation and hydrogen-bond reorientation, thereby lowering the activation energy for proton transfer, whereas excessively fast relaxation disrupts network continuity and hinders proton hopping, leading to increased activation barriers. In contrast, the absence of observable relaxation reflects a largely static hydrogen-bonded network, which lacks the dynamic adaptability required for optimized proton transport and thus exhibits intermediate activation energies. Furthermore, the necessity of segmented fitting for the proton-conduction activation energy in Pr-Hpda-H₂O directly motivates a re-examination of the applicability of the Grotthuss mechanism in solid-state systems. These findings demonstrate that proton conduction in the solid state arises not solely from static structural pathways, but from an optimal interplay between hydrogen-bond network topology and dynamic reorganization. This work provides a dynamic framework for understanding proton-conduction mechanisms and offers new guidance for the rational design of advanced proton-conducting materials.

Interfacial engineering of ZrO ₂ @Co-MOF heterostructures facilitates in situ surface reconstruction and drastically lowers the C–C bond cleavage energy barrier, enabling highly selective electrocatalytic valorization of glycerol to formic acid.

We introduce the Brønsted acid sites through the dopant electronic structure into gel. This achieves exceptional anhydrous conductivity from 1.9 × 10 ⁻³ S cm ⁻¹ at 233 K to 5.0 × 10 ⁻² S cm ⁻¹ at 433 K.

A MOF-derived NiO/γ-Fe ₂ O ₃ heterojunction sensor delivers record EG sensitivity and stability, enabled by engineered defects, mesopores and interfacial charge control.

The design of composition and morphology is a highly effective strategy for transforming solid metal–organic frameworks (MOFs) into hollow structures. In this study, we synthesized Mg-doped Bi₂WO₆ hollow tubes using bismuth metal–organic frameworks (CAU-17) as templates. This process involves the synthesis of solid CAU-17 microtubes, the etching of hollow tubes using Mg²⁺/WO₄²⁻ ions, and the formation of Mg/Bi₂WO₆ hollow microtubes through air annealing. The unique hollow structure and complex composition of Mg/Bi₂WO₆ contribute to its exceptional resistive gas sensing performance for detecting cyclohexane. The excellent cyclohexane sensing capabilities of Mg/Bi₂WO₆ are a result of the cooperative enhancement from its hollow structure (high utility factor) and Mg doping (optimized receptor and transducer functions), with its high selectivity being fundamentally governed by the favorable adsorption thermodynamics and kinetics of cyclohexane on its surface. The Mg/Bi₂WO₆ (ω_Mg = 0.2 wt.%) sensor exhibits remarkable sensitivity (50 ppm, R_a/R_g = 67), detecting cyclohexane as low as 0.1 ppm at 275 °C (R_a/R_g = 1.2). Additionally, it demonstrates excellent selectivity and outstanding stability for cyclohexane, underscoring its potential for practical applications in the clinical diagnosis of tuberculosis patients. This work presents a novel strategy for the rational design of hollow tube metal oxides with superior resistive gas sensing capabilities, paving the way for future advancements in multifunctional materials. Graphical abstract

Proton conduction is closely linked to dielectric relaxation behavior, where non-Debye relaxation leads to higher activation energy for proton transport, whereas its absence results in lower activation energy.