Study on Supported Triamino-functionalized Ionic Liquids for Carbon Dioxide Capture

The CO2 capture performance of two novel amino acid ionic liquid (AAIL)-based adsorbents was studied. The sorbents were synthesized by immobilizing two triamino-functionalized ionic liquids (i.e., 1-aminoethyl-3-methylimidazolium lysine ([AEMIM][Lys]) and 1-aminopropyl-3-methylimidazolium lysine ([APMIM][Lys])) into two types of supports (i.e., mesoporous silica SBA-15 and polymer poly(methyl methacrylate) (PMMA)) with different loadings. [AEMIM][Lys] and [APMIM][Lys] with one additional amino group in their cations are efficient at enhancing the CO2 capacity of subsequent supported AAILs, as higher numbers of functional amino groups in AAILs significantly increase their CO2 capture capacity. The prepared samples were characterized by Nuclear Magnetic Resonance (NMR), Brunauer-Emmet-Teller (BET) analysis, thermogravimetric analysis (TGA) decomposition, and X-ray diffraction (XRD). The samples were also investigated for CO2 sorption performance by CO2 isotherms and TGA kinetics. 50 wt% [AEMIM][Lys]-immobilized on PMMA showed the best CO2 capture capacities of 1.5 mmol/g-sorb at adsorption conditions of 30°C and under 15% CO2 inlet concentration

Directional Oxidation of Pyrite in Acid Solution

This study aimed to investigate the oxidation mechanism of pyrite crystallographic direction by cutting pyrite samples to expose their (100), (110), and (111) planes. Differences in the oxidation rates of pyrite planes in acid solution were determined. The morphological changes of pyrite were evaluated by scanning electron microscopy and hyperdepth-3D microscopy. The oxidation products of pyrite were examined by Raman spectroscopy and X-ray photoelectron spectroscopy. Results showed that the aqueous oxidation of pyrite produced Fe(OH)3, Fe2O3, Fe2(SO4)3, and S8 on the surface. Moreover, the morphologies of corrosion patterns differed from one crystal plane to another: square, rectangular, and triangular etch pits were found on the (100), (110), and (111) planes, respectively. The corrosion patterns reflected the symmetrical arrangement of the crystallographic planes in the lattice on which they formed

Oxygen Vacancy Enhanced Proton Transfer to Boost Carbamate Decomposition Kinetics with Tunable Heterostructure Ni/NiO

Catalytic carbamate decomposition is a feasible option for reducing the heat duty of amine solvent regeneration during the chemisorption of CO2 capture; advanced material with excellent proton transfer and exchange performance is crucial to boost the decomposition kinetics in an alkaline environment. Here, we prepared magnetic heterostructure Ni/NiO nanocatalysts with tunable Ni(0) nanoparticles and NiO support. The heterointerface of the proposed materials creates abundant surface oxygen vacancies (OVs) and offers abundant reactive active sites ascribed to the special electron transfer scheme of Ni0–NiO. The generated surface hydroxyls and unsaturated coordinated Ni, respectively, provide transferable protons and electrons, involved in the deprotonation of RNH3+ and C–N break of RNHCOO–. Thus, the obtained nanomaterials achieved considerably improved CO2 desorption of up to 3 mmol/min for a CO2-saturated monoethanolamine solvent, representing a substantial (approximately 50%) increase over the catalyst-free case. The reinforcement mechanism of OV generation by the Ni/NiO heterostructure and the induced proton transfer were revealed through in situ spectroscopic measurement and theoretical calculations. The results verified that the OVs stimulate the production of surface hydroxyls and water-assisted proton hopping, providing an advantageous condition for carbamate decomposition

Oxygen Vacancy Enhanced Proton Transfer to Boost Carbamate Decomposition Kinetics with Tunable Heterostructure Ni/NiO

Catalytic carbamate decomposition is a feasible option for reducing the heat duty of amine solvent regeneration during the chemisorption of CO2 capture; advanced material with excellent proton transfer and exchange performance is crucial to boost the decomposition kinetics in an alkaline environment. Here, we prepared magnetic heterostructure Ni/NiO nanocatalysts with tunable Ni(0) nanoparticles and NiO support. The heterointerface of the proposed materials creates abundant surface oxygen vacancies (OVs) and offers abundant reactive active sites ascribed to the special electron transfer scheme of Ni0–NiO. The generated surface hydroxyls and unsaturated coordinated Ni, respectively, provide transferable protons and electrons, involved in the deprotonation of RNH3+ and C–N break of RNHCOO–. Thus, the obtained nanomaterials achieved considerably improved CO2 desorption of up to 3 mmol/min for a CO2-saturated monoethanolamine solvent, representing a substantial (approximately 50%) increase over the catalyst-free case. The reinforcement mechanism of OV generation by the Ni/NiO heterostructure and the induced proton transfer were revealed through in situ spectroscopic measurement and theoretical calculations. The results verified that the OVs stimulate the production of surface hydroxyls and water-assisted proton hopping, providing an advantageous condition for carbamate decomposition

Sulfur Migration Enhanced Proton-Coupled Electron Transfer for Efficient CO₂ Desorption with Core-Shelled C@Mn₃O₄

Transforming hazardous species into active sites by ingenious material design was a promising and positive strategy to improve catalytic reactions in industrial applications. To synergistically address the issue of sluggish CO2 desorption kinetics and SO2-poisoning solvent of amine scrubbing, we propose a novel method for preparing a high-performance core–shell C@Mn3O4 catalyst for heterogeneous sulfur migration and in situ reconstruction to active –SO3H groups, and thus inducing an enhanced proton-coupled electron transfer (PCET) effect for CO2 desorption. As anticipated, the rate of CO2 desorption increases significantly, by 255%, when SO2 is introduced. On a bench scale, dynamic CO2 capture experiments reveal that the catalytic regeneration heat duty of SO2-poisoned solvent experiences a 32% reduction compared to the blank case, while the durability of the catalyst is confirmed. Thus, the enhanced PCET of C@Mn3O4, facilitated by sulfur migration and simultaneous transformation, effectively improves the SO2 resistance and regeneration efficiency of amine solvents, providing a novel route for pursuing cost-effective CO2 capture with an amine solvent