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The intracrystalline ionic environment in microporous zeolite can remarkably modify the excess chemical potential of adsorbed reactants and transition states, thereby influencing the catalytic turnover rates. However, a limit of the rate enhancement for aqueous‐phase dehydration of alcohols appears to exist for zeolites with high ionic strength. The origin of such limitation has been hypothesized to be caused by the spatial constraints in the pores via, e.g. size exclusion effects. It is demonstrated here that the increase in turnover rate as well as the formation of a maximum and the rate drop are intrinsic consequences of the increasingly dense ionic environment in zeolite. The molecularly sized confines of zeolite create a unique ionic environment that monotonically favors the formation of alcohol‐hydronium ion complexes in the micropores. The zeolite microporous environment determines the kinetics of catalytic steps and tailors the impact of ionic strength on catalytic rates. [ABSTRACT FROM AUTHOR]

Due to the high theoretical specific capacity and low cost of Sn, developing Sn‐based anode materials with long life is the key to their practical applications in lithium‐ion batteries. Herein, novel hierarchically porous NiSn alloys with interconnected ligament‐channel networks are synthesized via a two‐step dealloying strategy, involving corrosion of an Al97.5Ni2Sn0.5 precursor in NaOH, followed by partially etching Ni in HNO3. The architecture of the obtained NiSn‐3 h alloy contains the ligaments with the scale of about 115.2 nm and nanowalls with a thickness of several nanometers on the ligament surface, which can enhance the electron/ion transport kinetics and improve the tolerance to volume variation. The NiSn‐3h electrode exhibits superior Li storage performance in terms of satisfactory rate performance and excellent cycling stability with a reversible capacity of 213.9 mAh g−1 at 1 A g−1 after 1000 cycles. More importantly, the Li storage mechanism of NiSn‐3h is unveiled by operando X‐Ray diffraction, revealing the formation of lithiation products with low crystallinity at the end of discharge. In addition, on‐line differential electrochemical mass spectroscopy is used to detect the gas evolution of the NiSn‐3h electrode during the discharge–charge processes. [ABSTRACT FROM AUTHOR]

Ag-Zn alloys are identified as highly active and selective electrocatalysts for CO2 reduction reaction (CO2RR), while how the phase composition of the alloy affects the catalytic performances has not been systematically studied yet. In this study, we fabricated a series of Ag-Zn alloy catalysts by magnetron co-sputtering and further explored their activity and selectivity towards CO2 electroreduction in an aqueous KHCO3 electrolyte. The different Ag-Zn alloys involve one or more phases of Ag, AgZn, Ag5Zn8, AgZn3, and Zn. For all the catalysts, CO is the main product, likely due to the weak CO binding energy on the catalyst surface. The Ag5Zn8 and AgZn3 catalysts show a higher CO selectivity than that of pure Zn due to the synergistic effect of Ag and Zn, while the pure Ag catalyst exhibits the highest CO selectivity. Zn alloying improves the catalytic activity and reaction kinetics of CO2RR, and the AgZn3 catalyst shows the highest apparent electrocatalytic activity. This work found that the activity and selectivity of CO2RR are highly dependent on the element concentrations and phase compositions, which is inspiring to explore Ag-Zn alloy catalysts with promising CO2RR properties. [ABSTRACT FROM AUTHOR]

The intracrystalline ionic environment in microporous zeolite can remarkably modify the excess chemical potential of adsorbed reactants and transition states, thereby influencing the catalytic turnover rates. However, a limit of the rate enhancement for aqueous-phase dehydration of alcohols appears to exist for zeolites with high ionic strength. The origin of such limitation has been hypothesized to be caused by the spatial constraints in the pores via, e.g., size exclusion effects. It is demonstrated here that the increase in turnover rate as well as the formation of a maximum and the rate drop are intrinsic consequences of the increasingly dense ionic environment in zeolite. The molecularly sized confines of zeolite create a unique ionic environment that monotonically favors the formation of alcohol-hydronium ion complexes in the micropores. The zeolite microporous environment determines the kinetics of catalytic steps and tailors the impact of ionic strength on catalytic rates., (© 2022 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

Electrochemical CO 2 reduction (CO 2 ER) to formate is an attractive approach for CO 2 utilization. Here, we report a nanoporous bismuth (np-Bi) catalyst fabricated by chemically dealloying a rapidly solidified Mg 92 Bi 8 alloy for CO 2 ER. The np-Bi catalyst exhibits a three-dimensional interconnected ligament-channel network structure, which can efficiently convert CO 2 to formate with a selectivity of ≤94% and an activity of 62 mA cm -2 in a wide potential range. Remarkably, the np-Bi catalyst delivers an industry-level current density of ∼500 mA cm -2 for formate production at a low overpotential of 420 mV in the flow cell. The outstanding CO 2 ER performance can be attributed to the enlarged surface area with abundant accessible active sites and highly curved surfaces with enhanced intrinsic activity. This work highlights the structural synergies for enhancing CO 2 ER.