Investigation of Key Electronic States in Layered Mixed Chalcogenides With a d0 Transition Metal as Li‐Ion Cathodes DOI Creative Commons
Khagesh Kumar, Neelam Sunariwal, Jacques Louis

и другие.

Advanced Functional Materials, Год журнала: 2024, Номер unknown

Опубликована: Сен. 6, 2024

Abstract Lithium‐rich transition metal chalcogenides are witnessing a revival as candidates for Li‐ion cathode materials, spurred by the boost in their capacities from transcending conventional redox processes based on cationic states and tapping into additional chalcogenide states. A particularly striking case is Li 2 TiS 3‐ y Se , which features d 0 metal. While end members expectedly inactive, substantial measured when both S present. Using X‐ray absorption spectroscopy, it shown that electronic structure of not simple combination members. The data confirm previous hypotheses that, 2.4 0.6 this behavior underpinned concurrent reversible only Se, identify key Moreover, wavelet transforms extended fine provide direct evidence formation short Se–Se units upon charging. study uncovers underpinnings intriguing reactivity highlights richness chemistry complex solids.

Язык: Английский

Comprehensive Understanding of the Structural Modulation Principles for Highly Efficient Photoelectrochemical/Photocatalytic Processes via X‐Ray Absorption Spectroscopy DOI Open Access
Tao Yi, Xiaolan Xu, Xiaodong Chen

и другие.

ChemCatChem, Год журнала: 2025, Номер unknown

Опубликована: Март 5, 2025

Abstract Photoelectrochemical (PEC) and photocatalytic (PC) reactions offer promising pathways toward the efficient conversion of intermittent solar energy into high value‐added chemicals. To improve efficiency energy, rational modulation both light absorbers surface sites is required for sunlight‐harvesting capacity reaction activity, yet depending on a comprehensive understanding process. In this regard, X‐ray absorption spectroscopy (XAS) plays critical role in probing electronic geometric structures active materials PEC PC reactions, thereby revealing related structure‒activity relationships providing guide further structural modulation. This review begins with principles PEC/PC reactions. The fundamental knowledge XAS then introduced, including basics near edge structure (XANES) extended fine (EXAFS), general experimental methods, situ technique. Furthermore, we provide several examples to illustrate how can be utilized reveal (e.g., water splitting, CO 2 reduction, N fixation). Finally, major challenges future opportunities exciting field are highlighted.

Язык: Английский

Процитировано

0
Nature of Reactive Sites in TS-1 from 15N Solid-State NMR and Ti K-Edge X-Ray Absorption Spectroscopic Signatures Upon Pyridine Adsorption DOI
Lukas Lätsch, Christoph J. Kaul, Alexander V. Yakimov

и другие.

Journal of the American Chemical Society, Год журнала: 2024, Номер unknown

Опубликована: Окт. 20, 2024

Ti-containing zeotypes, notably titanosilicalite-1 (TS-1), are prominent examples of heterogeneous catalysts that have found applications in selective oxidation processes with hydrogen peroxide. Despite extensive characterization studies including using various probe molecules to interrogate the nature and local environment Ti sites, their detailed structure (as well as reactivity) remains elusive. Here, we demonstrate low temperature

Язык: Английский

Процитировано

2
Simple Molecular Synthetic Approach to Dinuclear Titanium Sites in Ti-Containing Silica-Based Catalysts DOI
Takuya Hikino,

Yuka Kawakubo,

Takamichi Matsuno

и другие.

Chemistry of Materials, Год журнала: 2024, Номер 36(21), С. 10886 - 10894

Опубликована: Окт. 17, 2024

Ti-containing silica-based catalysts are widely used for various organic oxidation reactions. Recently, increasing attention has been paid to the catalytic role of dinuclear (SiO)3Ti–O–Ti(OSi)3 sites in titanosilicate zeolite TS-1. A promising experimental approach elucidating active is use model compounds with Ti sites. In this study, we report synthesis and properties a μ-oxo-bridged titanosiloxane compound site. cage siloxane (iBu7Si7O12)TiOiPr (mononuclear Ti-polyhedral oligomeric silsesquioxane (POSS)) prepared by reaction incompletely condensed POSS titanium tetraisopropoxide. Then, it converted species (iBu7Si7O12)2Ti2(μ-O) (dinuclear Ti-POSS) simple hydrolytic condensation TiOiPr groups. The addition H2O2 Ti-POSS leads formation bishydroperoxo complex, as revealed K-edge X-ray absorption fine structure analysis. Dinuclear possesses high activity cyclohexene epoxidation reaction, indicating that can function efficient catalytically These findings contribute comprehension exhibited within catalysts.

Язык: Английский

Процитировано

1
Nature of Reactive Sites in TS-1 from 15N solid-state NMR and Ti K-edge X-Ray Absorption Spectroscopic Signatures upon Pyridine Adsorption DOI Creative Commons
Lukas Lätsch, Christoph J. Kaul, Alexander V. Yakimov

и другие.

Опубликована: Авг. 2, 2024

Ti-containing zeotypes, notably titanosilicalite-1 (TS-1), are prominent examples of heterogeneous catalysts that have found applications in selective oxidation processes with hydrogen peroxide. Despite extensive characterization studies including the use various probe molecules to interrogate nature and local environment Ti sites, their detailed structure (as well as reactivity) remains elusive. Here, we demonstrate using low temperature 15N magic angle spinning (MAS) ssNMR spectroscopy adsorbed pyridine on TS-1 combined K-edge XANES a range samples (dehydrated, hydrated, contacted H2O2 pyridine) provides unique information regarding highlighting reactivity dynamic nature. While dehydrated shows only Lewis acid presence H2O generates Brønsted whose amount correlate water loading. Moreover, methodology – based applied library Ti-loadings absence extra-framework TiO2 also enables quantify sites establish structure-activity descriptor (ratio silanols vs. titanium). Complementary analysis computational modelling reveals reaction an acidic bridging silanol Ti-(OH)-Si, upon hydrolysis one Ti-O-Si linkage, where expands its coordination from four pentacoordinated according XAS.

Язык: Английский

Процитировано

0
Investigation of Key Electronic States in Layered Mixed Chalcogenides With a d0 Transition Metal as Li‐Ion Cathodes DOI Creative Commons
Khagesh Kumar, Neelam Sunariwal, Jacques Louis

и другие.

Advanced Functional Materials, Год журнала: 2024, Номер unknown

Опубликована: Сен. 6, 2024

Abstract Lithium‐rich transition metal chalcogenides are witnessing a revival as candidates for Li‐ion cathode materials, spurred by the boost in their capacities from transcending conventional redox processes based on cationic states and tapping into additional chalcogenide states. A particularly striking case is Li 2 TiS 3‐ y Se , which features d 0 metal. While end members expectedly inactive, substantial measured when both S present. Using X‐ray absorption spectroscopy, it shown that electronic structure of not simple combination members. The data confirm previous hypotheses that, 2.4 0.6 this behavior underpinned concurrent reversible only Se, identify key Moreover, wavelet transforms extended fine provide direct evidence formation short Se–Se units upon charging. study uncovers underpinnings intriguing reactivity highlights richness chemistry complex solids.

Язык: Английский

Процитировано

0