Understanding the Reactive Adsorption of H2 S and CO2 in Sodium-Exchanged Zeolites

Review of Theoretical and Computational Studies of Bulk and Single Atom Catalysts for H2 S Catalytic Conversion

Catalytic conversion of hydrogen sulfide (H2 S) plays a vital role in environmental protection and safety production. In this review, recent theoretical advances for catalytic conversion of H2 S are systemically summarized. Firstly, different mechanisms of catalytic conversion of H2 S are elucidated. Secondly, theoretical studies of catalytic conversion of H2 S on surfaces of metals, metal compounds, and single-atom catalysts (SACs) are systematically reviewed. In the meantime, various strategies which have been adopted to improve the catalytic performance of catalysts in the catalytic conversion of H2 S are also reviewed, mainly including facet morphology control, doped heteroatoms, metal deposition, and defective engineering. Finally, new directions of catalytic conversion of H2 S are proposed and potential strategies to further promote conversion of H2 S are also suggested: including SACs, double atom catalysts (DACs), single cluster catalysts (SCCs), frustrated Lewis pairs (FLPs), etc. The present comprehensive review can provide an insight for the future development of new catalysts for the catalytic conversion of H2 S.

Combined Adsorption and Reaction in the Ternary Mixture N2, N2O4, NO2 on MIL-127 Examined by Computer Simulations

A high selectivity of NO _x over N₂ (simulating air) is found in silico when studying the adsorption of the ternary mixture N₂O₄/NO₂/N₂ on the metal-organic framework MIL-127(Fe) by molecular simulations under consideration of the recombination reaction N₂O₄ ↔ 2NO₂. The number of N atoms in nitrogen oxides NO _x and that in N₂ is used to define a selectivity of the combined adsorption and chemical recombination that can reach values of about 1000.

Achieving high-performance nitrate electrocatalysis with PdCu nanoparticles confined in nitrogen-doped carbon coralline

Complex porous carbon nanostructures with homogeneously embedded nanoparticles and intricate architectures show promise as high-performance catalysts. Herein, we demonstrate a direct surfactant co-assembly approach for the fabrication of well-dispersed PdCu nanoparticles encapsulated in N-doped porous carbon with three-dimensional coralline structures. Owing to their porous features and unique frameworks, the PdxCuy@N-pC coralline-like nanostructures offer large surface areas, accessible active sites, and excellent nitrate electrocatalytic ability. The composite catalyst Pd4Cu4@N-pC exhibits outstanding catalytic performance with a high nitrate removal rate of ∼95%, nitrogen selectivity of ∼80%, and removal capacity of 22 000 mg N per g PdCu. More importantly, the present work opens up a broad horizon for architectures of nanoparticles confined in coralline-like 3D porous carbon structures with superior performance and promising large-scale applications.

Reaction Ensemble Monte Carlo Simulations of CO2 Absorption in the Reactive Ionic Liquid Triethyl(octyl)phosphonium 2-Cyanopyrrolide

The absorption of CO₂ into an aprotic heterocyclic anion ionic liquid (IL) is modeled using reaction ensemble Monte Carlo (RxMC) with the semigrand reaction move. RxMC has previously been unable to sample chemical equilibrium involving molecular ions in nanostructured liquids due to the high free-energy requirements to open and close cavities and restructure the surrounding environment. Our results are validated by experiments in the modeled IL, triethyl(octyl)phosphonium 2-cyanopyrrolide ([P₂₂₂₈][cnp]), and in a close analog with longer alkyl chains on the cation. Heats of absorption and reaction from both experiment and simulation are exothermic and of comparable magnitude. Replacing experimental Henry's constants with their simulated counterparts improves the accuracy of a Langmuir-type model at moderate pressures. Nonidealities that affect chemical equilibrium are identified and calculated with high precision.

First principles Monte Carlo simulations of unary and binary adsorption: CO2, N2, and H2O in Mg-MOF-74

Dative bonding of adsorbate molecules onto coordinatively-unsaturated metal sites in metal–organic frameworks (MOFs) can lead to unique adsorption selectivities.