A computational study of phosphorus-doped graphdiynes and several corresponding oxides by simulated X-ray spectroscopy.

Controlled Growth Interface of Charge Transfer Salts of Nickel-7,7,8,8-Tetracyanoquinodimethane on Surface of Graphdiyne

Electronic structures and spectral characteristics of the six C32 fullerene isomers.

ABSTRACTThe near-edge X-ray absorption fine structure (NEXAFS) spectra and the X-ray photoelectron spectroscopy (XPS), as well as the geometrical structures of two C isomers (C(16), C(17)) and their corresponding chlorinated derivatives (C(16) Cl, C(17)Cl) which were newly purified have been investigated by the density functional theory (DFT). The variations of molecular structure, electronic structure and simulated spectra for C isomers after chlorination have been illustrated. Then, the above-mentioned C isomers and their chlorinated derivatives have been identified by the NEXAFS and XPS spectra which show the dependence on the local structure. Furthermore, we have also traced the source of the features in the total spectra by the spectral exploration of each component, which is very helpful for the further study of newly captured fullerene isomers and their derivatives.In this manuscript, we have performed first-principles simulation of the C1s X-ray photoelectron spectra (XPS) and near-edge X-ray absorption fine structure spectra (NEXAFS) for two C86 fullerene isomers and the related chlorinated species. The variations of molecular structure, electronic structure and simulated spectra for C86 isomers after chlorination have been illustrated. The above-mentioned C86 isomers and their chlorinated derivatives were identified by the NEXAFS and XPS spectra which show strong dependence on the local structure. Furthermore, we have also traced the source of the features in the total spectra by the spectral exploration of each component. The investigations on newly synthesized fullerenes and derivatives are effectively valuable and stimulative for the experimental researches in future.

ABSTRACTThe X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy of the carbon K-edge for the two nano onion-like fullerenes (NOLFs) C isomers have been in theory performed by density functional theory (DFT) method. We have especially focussed on the structure-spectroscopy relationship by exploring in detail and analyzing systematically the calculated spectra. Both the XPS and NEXAFS spectra show dependence on molecular structures, so these two spectroscopic techniques can be used to identify the two NOLFs C isomers. Meanwhile, the spectral components of each C isomer based on the local environment of carbon atoms have been calculated at the same level. Furthermore, we have tested the feasibility of using the building block (BB) approach to quickly estimate the XPS and NEXAFS spectra in the NOLFs C system. Results show that applying the BB approach is impossible to predict the direct calculated results for the NOLFs C. Additionally, fullerene C(D) as an isomer of C can be distinguished from the two C isomers by the XPS and NEXAFS spectra.

Maximizing atomic utilization of precious metal-based catalysts is of great significance in heterogeneous catalysis, also becoming a useful strategy to develop efficient electrocatalysts for hydrog...

The chemisorbed structure for an aromatic molecule on a silicon surface plays an important part in promoting the development of organic semiconductor material science. The carbon K-shell x-ray photoelectron spectroscopy (XPS) and the x-ray absorption near-edge structure (XANES) spectra of the interfacial structure of an s-triazine molecule adsorbed on Si(100) surface have been performed by the first principles, and the landscape of the s-triazine molecule on Si(100) surface has been described in detail. Both the XPS and XANES spectra have shown their dependence on different structures for the pristine s-triazine molecule and its several possible adsorbed configurations. By comparison with the XPS spectra, the XANES spectra display the strongest structural dependency of all of the studied systems and thus could be well applied to identify the chemisorbed s-triazine derivatives. The exploration of spectral components originated from non-equivalent carbons in disparate local environments has also been implemented for both the XPS and XANES spectra of s-triazine adsorbed configurations.

The geometric and electronic structures of several possible adsorption configurations of the pyrazine (C4H4N2) molecule covalently attached to Si(100) surface, which is of vital importance in fabricating functional nano-devices, have been investigated using X-ray spectroscopies. The Carbon K-shell (1s) X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy of predicted adsorbed structures have been simulated by density functional theory with cluster model calculations. Both XPS and NEXAFS spectra demonstrate the structural dependence on different adsorption configurations. In contrast to the XPS spectra, it is found that the NEXAFS spectra exhibiting conspicuous dependence on the structures of all the studied pyrazine/Si(100) systems can be well utilized for structural identification. In addition, according to the classification of carbon atoms, the spectral components of carbon atoms in different chemical environments have been investigated in the NEXAFS spectra as well.

Boron-doped graphdiyne (B-GDY) material exhibits an excellent performance in electrocatalysis, ion transport, and energy storage. However, accurately identifying the structures of B-GDY in experiments remains a challenge, hindering further selection of suitable structures with the most ideal performance for various practical applications. In the present work, we employed density functional theory (DFT) to simulate the X-ray photoelectron spectra (XPS) and near-edge X-ray absorption fine-structure (NEXAFS) spectra of pristine graphdiyne (GDY) and six representative single boron-doped graphdiynes at the B and C K-edges to establish the structure-spectroscopy relationship. A notable disparity in the C 1s ionization potentials (IPs) between substituted and adsorbed structures is observed upon doping with a boron atom. By analyzing the C and B 1s NEXAFS spectra on energy positions, spectral widths, spectral intensities, and different spectral profiles, we found that the six single boron-doped graphdiyne configurations can be sensitively identified. Moreover, this study provides a reliable theoretical reference for distinguishing different single boron-doped graphdiyne structures, enabling accurate selection of B-GDY structures for diverse practical applications.

Boosting Electrocatalytic CO ₂ Reduction with Conjugated Bimetallic Co/Zn Polyphthalocyanine Frameworks

The possible configurations of pyrrole absorbed on a Si(100) surface have been investigated by x-ray photoelectron spectroscopy (XPS) and near-edge x-ray absorption fine structure (NEXAFS) spectra. The C-1s XPS and NEXAFS spectra of these adsorption configurations have been calculated by using the density functional theory (DFT) method and full-core hole (FCH) approximation to investigate the relationship between the adsorption configurations and the spectra. The result shows that the XPS and NEXAFS spectra are structurally dependent on the configurations of pyrrole absorbed on the Si(100) surface. Compared with the XPS, the NEXAFS spectra are relatively sensitive to the adsorption configurations and can accurately identify them. The NEXAFS decomposition spectra produced by non-equivalent carbon atoms have also been calculated and show that the spectral features vary with the diverse types of carbon atoms and their structural environments.

BiO _2-x Nanosheets with Surface Electron Localizations for Efficient Electrocatalytic CO ₂ Reduction to Formate

Selective hydrogenation of alkynes to alkenes remains challenging in the field of catalysis due to the ease of over-hydrogenated of alkynes to alkanes. Favorably, the incorporation of metal nanopar...

Computational Prediction of Graphdiyne-Supported Three-Atom Single-Cluster Catalysts

Decrypting the Influence of Axial Coordination on the Electronic Microenvironment of Co-N ₅ Site for Enhanced Electrocatalytic Reaction

Polymerizable organic silane molecules such as 3-(trimethoxysilyl)propylmethacrylate (γ-MPS) have been grafted onto the surface of ZrO2 powders, via hydroxyl groups, to obtain hybrid ‘macromonomers’. A combination of x-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy and 29Si nuclear magnetic resonance (NMR) spectroscopy have been employed to study the interaction between organic silane molecules and the surface of the ZrO2 powders. The core-level XPS regions, Zr3d, O1s, C1s and Si2p, have been studied to determine the nature of chemical bonding between the organic grafted monomer and inorganic phase and correlated with NMR results. Based upon the results obtained, it is proposed that grafting results in γ-MPS bonded to the ZrO2 powder surface via ZrOSi bonds accompanied by interlinkage of γ-MPS molecules through SiOSi bonding. © 1997 John Wiley & Sons, Ltd.