Single atoms and nanoclusters of Fe, Ni, Co, Cu, and Mn are systematically designed and embedded in a well‐defined C1N1‐type material that has internal cavities of ≈0.6 nm based on four N atoms. These N atoms serve as perfect anchoring points for the nucleation of small nanoclusters of different metal natures through the creation of metal‐nitrogen (TM‐N4) bonds. After pyrolysis at 800 °C, TM@CNx‐type structures are obtained, where TM is the transition metal and x < 1. Fe@CNx and Co@CNx are the most promising for oxygen reduction reaction and hydrogen evolution reaction, respectively, with a Pt‐like performance, and Ni@CNx is the most active for oxygen evolution reaction (OER) with an EOER of 1.59 V versus RHE, far outperforming the commercial IrO2 (EOER = 1.72 V). This systematic and benchmarking study can serve as a basis for the future design of advanced multi‐functional electrocatalysts by modulating and combining the metallic nature of nanoclusters and single atoms.

The study of novel two-dimensional structures for potential applications in photocatalysis or in optoelectronics is a challenging task. In this work, first-principles calculations have been carried out to explore the...

Metal–organic frameworks (MOFs) have attracted much attention for the effective capture of contaminants from air. Herein, density functional theory (DFT) calculations and grand canonical Monte Carlo (GCMC) simulations were combined to systematically assess the adsorption performance of the cagelike UiO-66 nanoporous MOF functionalized by metal­(II) catecholate [CatM­(II), where M­(II) = Mg­(II), Mn­(II), Fe­(II), Co­(II), Ni­(II), Cu­(II), Zn­(II), Pd­(II), and Pt­(II)] with respect to NO x potentially present at very low concentration (from the ppm to ppb levels). The adsorption modes and energetics of NO x toward metal­(II) catecholate functions were first examined systematically using cluster DFT calculations in order to determine the optimum metal­(II) for effective NO x capture. The best CatFe­(II) was further incorporated in the crystal structure of UiO-66 and force-field parameters to accurately describe the specific interactions between Fe­(II), and both NO x were derived from periodic DFT calculations and further implemented in a GCMC scheme to predict the adsorption isotherms in a whole range of gas pressure. These calculations revealed that UiO-66-CatFe­(II) exhibits steep-adsorption isotherms for both NO x , leading to excellent adsorption uptake at very low gas pressure (from 10–9–10–4 bar). This finding complements the portfolio of nanoporous materials that has so far been almost exclusively tested in operation conditions at much higher NO x concentration (>1000 ppm).

Competative adsorption of O2 and CO2 in FAU zeolites.

Emissions of diesel exhaust gas in confined work environments are a major health and safety concern, because of the exposition to nitrogen oxides (NOx). Removal of these pollutants from exhaust...

Silanols are key players in the application performance of zeolites, yet, their localization and hydrogen bonding strength need more studies. The effects of post-synthetic ion exchange on nanosized chabazite (CHA), focusing on the formation of silanols, were studied. The significant alteration of the silanols of the chabazite nanozeolite upon ion exchange and their effect on the CO2 adsorption capacity was revealed by solid-state nuclear magnetic resonance (NMR), Fourier-transform infrared (FTIR) spectroscopy, and periodic density functional theory (DFT) calculations. Both theoretical and experimental results revealed changing the ratio of extra-framework cations in CHA zeolites changes the population of silanols; decreasing the Cs+/K+ ratio creates more silanols. Upon adsorption of CO2, the distribution and strength of the silanols also changed with increased hydrogen bonding, thus revealing an interaction of silanols with CO2 molecules. To the best of our knowledge, this is the first evidence of the interplay between alkali-metal cations and silanols in nanosized CHA.

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