Analytical Chemistry
DOI: 10.1021/acs.analchem.3c01178
In Situ Spectroscopic Study of CO2 Capture and Methanation over Ni−Ca Based Dual Functional Materials
In this study, we investigate the mechanism of CCR to CH4 over Al2O3-supported Ni−Ca DFMs. Various spectroscopic analyses, including time-resolved in situ XRD and XAS, were conducted during CO2 capture and the subsequent H2-reduction steps.
Abstract
Carbon dioxide capture and reduction (CCR) to CH4 using dual-functional materials (DFMs) have recently attracted significant attention as a promising strategy for carbon capture and utilization. In this study, we investigate the mechanism of CCR to CH4 over Al2O3-supported Ni−Ca DFMs (Ni−Ca/Al2O3) under cyclic feeds of model combustion exhaust (2.5 % CO2+0 or 10 % O2/N2) and H2 at 500 °C. Various spectroscopic analyses, including time-resolved in situ X-ray diffraction and X-ray absorption spectroscopy, were conducted during CO2 capture and the subsequent H2-reduction steps. Based on these analyses, we propose a mechanism of CCR to CH4 over Ni−Ca based DFMs. During the CO2 capture step, the Ni0 species underwent complete oxidation in the presence of O2 to yield NiO. Subsequently, CO2 was captured through the interaction between the CaO surface and CO2, resulting in the formation of CaCO3 layers on the CaO particles. When the gas flow was switched to H2, NiO was partially to provide Ni0 sites, which acted as active sites for H2-reduction of the adjacent CaCO3 layers to yield CaO and gas-phase products, CH4 and H2O.
Interparticle Hydrogen Spillover in Enhanced Catalytic Reactions
We analyze examples of enhanced catalysis based on interparticle (reverse) hydrogen spillover. Simple physical mixtures of powdered catalysts containing metal catalysts of H2 dissociation/recombination and solid catalysts with active sites for substrate activation significantly enhance catalytic reactions, including aromatic hydrogenation, CO2 methanation, deoxydehydration of polyols, aromatization of lower paraffins, and direct coupling of benzene and alkanes.
Abstract
Interparticle hydrogen spillover is the phenomenon of H migration over different catalyst particles, which should be a physical mixture of at least two solid catalysts. In this review, we analyze examples of enhanced catalysis based on interparticle (reverse) hydrogen spillover. Simple physical mixtures of powdered catalysts containing metal catalysts of H2 dissociation/recombination and solid catalysts with active sites for substrate activation significantly enhance catalytic reactions. These reactions include aromatic hydrogenation, CO2 methanation, and the deoxydehydration of polyols, aromatization of lower paraffins, and direct coupling of benzene and alkanes. The acceleration effect and proposed reaction pathway of each example involving interparticle (reverse) hydrogen spillover are summarized. Simple reaction systems comprising physical mixtures of at least two powdery solid catalysts should enable unique catalysis in the future with the aid of interparticle (reverse) hydrogen spillover.
A novel Z‐scheme heterojunction g‐C3N4/g‐C3N4/Pr6O11 for efficient visible‐light photocatalytic degradation of sulfonamide
A novel Z-scheme g-C3N4/g-C3N4/Pr6O11 heterojunction was fabricated by facile one-pot synthesis using melamine, urea, and praseodymium nitrate as co-precursors. The optimized 5wt%g-C3N4/g-C3N4/Pr6O11 heterojunction exhibited the highest degradation efficiency for sulfonamide under visible light irradiation. It was demonstrated by QSAR prediction and the growth test of wheat seeds that solutions degraded by photocatalysts showed good biocompatibility.
Photocatalytic technology, as an environmentally friendly technology, has a great application promise in the treatment of environmental pollutants caused by residual pharmaceuticals emissions. The Z-scheme heterojunction of g-C3N4/g-C3N4/Pr6O11 (Pr/CN) was successfully prepared by employing melamine, urea, and praseodymium nitrate as co-precursors. The structure composition and photoelectrochemical properties were characterized by XRD, XPS, EDS, SEM, FETEM, UV–Vis, EIS, photocurrent, and PL analyses. The optimized 5wt%Pr/CN heterojunction degrade 98% of SCP, 85% of SMM, and 87% of SDM, respectively. Taking SCP as an example, the degradation rate is 8 and 11.2 times higher than that of the g-C3N4/g-C3N4 homojunction and g-C3N4, respectively. The remarkable photocatalytic efficiency of Pr/CN heterojunction could be ascribed to enhanced visible light absorption and enhanced migration and separation of photogenerated charge carriers. Furthermore, the degradation products and degradation pathways of SCP and SMM were established by HPLC-MS/MS analysis. In addition, the toxicity of the intermediate was evaluated with quantitative structure–activity relationship (QSAR) prediction and the biocompatibility of sulfonamide-degrading solution over the Pr/CN photocatalyst was verified by the growth of wheat seeds.
Regularly Tuning Quantum Interference in Single‐Molecule Junctions through Systematic Substitution of Side Groups with Varied Electron Effects†
Destructive quantum interference of the m-OPE molecules was consistently regulated by substituents with progressively heightened electron effect.
Comprehensive Summary
Investigating the quantum interference effect in single molecules is essential to comprehensively understand the underlying mechanism of single-molecule charge transport. In this study, we employed the mother molecule m-OPE and introduced a series of side groups with various electronic effects at the 2-position of the central phenyl ring, creating four daughter m-OPE derivatives. The single molecular conductivities of these molecule wires were measured using the scanning tunneling microscope breaking junction technique. Our findings demonstrate that the substitutions regularly modulate the destructive quantum interference occurring within the m-OPE molecules. By combining optical and electrochemical investigations, along with density functional theory computations, we discover that the conductivity of the molecules corresponds to the electron-donating/withdrawing ability of the substituents. Specifically, by adjusting the electron structures of the molecular backbone, we can systematically tailor the destructive quantum interference in the m-OPE molecules.
Reduced Macrophage Uptake of Nanoparticles through Surface Modification of Polypeptides with Valine Residues†
The incorporation of valine residues into the polypeptide coatings significantly reduced the macrophage uptake of the nanoparticles, which was not observed for the nanoparticles modified with other amino acid residues like leucine, phenylalanine, isoleucine, and norvaline.
Comprehensive Summary
The structural and surface properties of nanomedicines play an important role in determining their biological fate. Surface chemistry of nanomedicines is one of the key parameters, where researchers used various strategies such as PEGylation to avoid the undesired clearance of nanoparticles (NPs) for enhanced targeting effect. Nevertheless, the fine-tuning of surface chemistry through polymer functionalization remains largely unexplored. In this concise report, we find that the incorporation of only 10 mol% valine residues into the surface-anchored poly(L-glutamic acid) significantly lowered the macrophage uptake of NPs. The introduction of other hydrophobic amino acid residues, however, increased the NPs internalization instead. The chirality and the side-chain structure of valine played an important role in the unexpected uptake behavior. We believe this work highlights the impact of slight changes of the surface-anchored polymer structure on the behavior of NPs, drawing people's attention to the careful design of surface chemistry to optimize the nanomedicine design.
Photoinduced Dehalocyclization to Access Oxindoles Using Formate as a Reductant
A general protocol for the photoinduced dehalocyclization of ortho-halophenylacrylamides with formate has been reported using a CO2 radical anion to access substituted oxindoles.
Comprehensive Summary
Herein, we report an efficient and practical protocol for the photoinduced dehalocyclization of ortho-halophenylacrylamides with formate by the engagement of a CO2 radical anion to access substituted oxindoles. This method proceeds smoothly under mild conditions and exhibits a wide range of substrate as well as remarkable functional group compatibility.
C—F Bond Insertion into Indoles with CHBr2F: An Efficient Method to Synthesize Fluorinated Quinolines and Quinolones
A mild and practical method for synthesizing fluorinated quinoline derivatives, which have a wide range of applications in pharmaceuticals, materials, and organic synthesis, was described through C—F bond insertion into indoles using CHBr2F. The simple conditions, readily availability of CHBr2F, as well as the versatility of the transformations make this strategy very powerful in synthesizing 3-fluoroquinoline and 3-fluoroquinolone.
Comprehensive Summary
A mild and practical method for synthesizing fluorinated quinoline derivatives, which have a wide range of applications in pharmaceuticals, materials, and organic synthesis, was described through C—F bond insertion into indoles using CHBr2F. The simple conditions, readily availability of CHBr2F, as well as the versatility of the transformations make this strategy very powerful in synthesizing 3-fluoroquinoline and 3-fluoroquinolone. The mechanistic studies reveal that bromofluorocarbene generated in-situ under basic condition was the key intermediate.
2022 John C. Warner early career researcher prize
Technological Advancement and Trend in Selective Bioanalytical Sample Extraction through State of the Art 3-D Printing Techniques Aiming ‘Sorbent Customization as per need’
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