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Le Chatelier's principle is a basic rule in textbook defining the correlations of reaction activities and specific system parameters (like concentrations), serving as the guideline for regulating chemical/catalytic systems. Here we report a model system breaking this constraint in O2 electroreduction in mixed dioxygen. We unravel the central role of creating single-zinc vacancies in a crystal structure that leads to enzyme-like binding of the catalyst with enhanced selectivity to O2, shifting the reaction pathway from Langmuir-Hinshelwood to an upgraded triple-phase Eley-Rideal mechanism. The model system shows minute activity alteration of H2O2 yields (25.89~24.99 mol gcat−1 h−1) and Faradaic efficiencies (92.5%~89.3%) in the O2 levels of 100%~21% at the current density of 50~300 mA cm−2, which apparently violate macroscopic Le Chatelier's reaction kinetics. A standalone prototype device is built for high-rate H2O2 production from atmospheric air, achieving the highest Faradaic efficiencies of 87.8% at 320 mA cm−2, overtaking the state-of-the-art catalysts and approaching the theoretical limit for direct air electrolysis (~345.8 mA cm−2). Further techno-economics analyses display the use of atmospheric air feedstock affording 21.7% better economics as comparison to high-purity O2, achieving the lowest H2O2 capital cost of 0.3 $ Kg−1. Given the recent surge of demonstrations on tailoring chemical/catalytic systems based on the Le Chatelier's principle, the present finding would have general implications, allowing for leveraging systems "beyond" this classical rule. The principle of Le Chatelier is a fundamental concept in textbooks, serving as a guiding principle for controlling chemical and catalytic systems. In this study, the authors present an oxygen electroreduction system based on a single zinc vacancy catalyst, which operates in a manner that extends "beyond" Le Chatelier's principle. [ABSTRACT FROM AUTHOR]

High‐entropy materials are composed of five or more metal elements with equimolar or near‐equimolar concentrations within one crystal structure, which offer remarkable structural properties for many applications. Despite previously reported entropy‐driven stabilization mechanisms, many high‐entropy materials still tend to decompose to produce a variety of derivatives under operating conditions. In this study, we use transition‐metal (Ni, Co, Ni, Zn, V)‐based high‐entropy metal–organic frameworks (HE‐MOFs) as the precursors to produce different derivatives under acidic/alkaline treatment. We have shown that HE‐MOFs and derivatives have shown favorable kinetics for N2 electrofixation in different pH electrolytes, specifically cathodic nitrogen reduction reaction in acidic media and anodic oxygen evolution reaction in alkaline media. To buffer the pH mismatch, we have further constructed an asymmetric acidic/alkaline device prototype by using bipolar membranes. As expected, the prototype showed remarkable activities, with an NH3 yield rate of 42.76 μg h−1 mg−1, and Faradaic efficiency of 14.75% and energy efficiency of 2.59%, which are 14.4 and 4.4 times larger than those of its symmetric acidic and alkaline counterparts, respectively. [ABSTRACT FROM AUTHOR]

The hydrogenation of small molecules (like O 2 and CO 2 ) often exhibits strong activity dependence on pHs because of discrepant proton donor environments. However, some catalysts can show seldom dependence on two-electron oxygen electroreduction, a sustainable route of O 2 hydrogenation to hydrogen peroxide (H 2 O 2 ). In this work, a pH-resistant oxygen electroreduction system arising from the pseudo-Jahn-Teller effect is demonstrated. Thorough operando Raman spectra, local environment analyses and density function theory simulations, the lattice distortion of TiO x F y that introduces the pseudo-Jahn-Teller effect contributing to regulating local pHs at electrode-electrolyte interfaces and the absorption/desorption of key *OOH intermediate is revealed. Consequently, as comparison to 78.6% activity attenuation for common catalyst, the TiO x F y displays minor activity decay (3.2%) in the pH range of 1-13 with remarkable Faradaic efficiencies (93.4-96.4%) and H 2 O 2 yield rates (595-614 mg cm -2  h -1 ) in the current densities of 100-1000 mA cm -2 . Further techno-economics analyses display the H 2 O 2 production cost dependent on pHs, giving the lowest H 2 O 2 price of $0.37 kg -1 . The present finding is expected to provide an additional dimension to pseudo-Jahn-Teller effect that leverages systems beyond traditional conception., (© 2024 Wiley‐VCH GmbH.)