Models for Single‐Site Heterogeneous Catalysts on Carbon: MoO2 Epoxidation Catalyst Anchored to a Fullerene DOI Creative Commons
Amol Agarwal, Yiqi Liu, Olga A. Kraevaya

et al.

ChemCatChem, Journal Year: 2024, Volume and Issue: 16(23)

Published: Aug. 16, 2024

Abstract Single‐site molybdenum dioxo catalysts, fullerenol/MoO 2 , are prepared via grafting precursor (DME)MoO Cl onto a highly polyhydroxylated fullerene (ful) and an isomerically‐pure well‐defined (ful*). These catalyst structures characterized by ICP‐OES, XPS, XANES, EXAFS, DRIFT, Raman, NMR spectroscopy, DFT. Mo 3d 5/2 XPS K‐edge XANES assign the oxidation state as Mo(VI). EXAFS data fitting reveals two Mo=O double Mo−O single bonds at distances of 1.7 1.9 Å, respectively, while stretchingl mode is observed ~950 cm −1 DRIFT Raman spectroscopy. align well with DFT computational results, supporting proposed structure Fullerene(‐μ‐O‐) M(=O) . Additionally, provides insight into energetically favorable sites for isomerically pure fullerenol. The scope mediated alkene epoxidation includes abiotic alkenes, natural occurring terpenes, conjugated olefins. For cyclooctene rate law first‐order in [Mo], near first order [olefin] zero‐order [t‐butyl hydroperoxide]. A plausible reaction mechanism involves peroxide addition then directly across peroxo bond forming epoxide product, consistent computation. Overall, shows promise sustainable structurally system versatile catalytic activity good recyclability.

Language: Английский

Reductive Upcycling of Polyolefins, Polyesters and Mixed Plastic Wastes to Valuable Chemicals: Bridging Chemical Catalysis With Plastic Waste Management DOI Open Access
Sahil Kumar, Devanshu Sajwan, Devendra Sharma

et al.

Advanced Sustainable Systems, Journal Year: 2025, Volume and Issue: unknown

Published: March 20, 2025

Abstract The unmatched applications of plastic commodities are evident from the enormous production, reaching over 400 million tons per year in recent times. Contrastingly, lack proper management leads to a large accumulation waste, majorly including polyolefins and polyesters. Conventional methods possess significant drawbacks like cost‐ineffectiveness greenhouse gas emissions. Over last decade, chemical processes have shown promising potential for but only hold 0.1% share recycling. catalytic offer excellent protocols obtain high‐value liquid fuels, waxes, chemicals waste. This review presents an elaborate discussion on state art reductive upcycling polyolefins, polyesters, mixed initially discusses alarming statistics plastics conventional approaches followed by introduction processes. Further, various recently reported strategies been elaborated detail catalyst deactivation, technoeconomic analysis, life cycle assessment deeper understanding current this research field. Finally, detailed summary along with existing challenges countermeasures is discussed open new avenues waste research.

Language: Английский

Citations

0
2H Quadrupolar Coupling Constant: A Spectroscopic Ruler for Transition Metal–Hydride Bond Distances in Molecular and Surface Sites DOI
Domenico Gioffrè, Christoph R. Müller, Scott R. Docherty

et al.

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: May 5, 2025

Transition metal hydrides (TMHs) find numerous applications across fields from catalysis to H2 storage. Yet, determining the structure of TMHs can remain a challenge, as hydrogen is difficult detect by X-ray based or classical spectroscopic techniques. Considering that deuterium isotope (D) quadrupolar nucleus (I = 1) and coupling constant (CQ) depends on distance between D its bonding partner E (dED), we evaluate this trend molecularly defined transition deuterides (TMDs) through systematic investigation TM block elements using both computations experiments. We show M-D bond (dMD) in [Å] correlates with CQ values [kHz] dMD 7.83(CQ + 28.7)-1/3─independently nature TM─with an accuracy >0.04-0.08 Å. Based experimental measured 2H solid-state NMR, simple correlation then used obtain distances two silica-supported TMDs (M Zr Ir), notable heterogeneous catalysts representing early late TMDs, where evaluating other means very challenging. ease measurement, method readily applicable large range diamagnetic terminal M-Ds, molecular surface sites, making NMR choice measure TMD distances.

Language: Английский

Citations

0
Models for Single‐Site Heterogeneous Catalysts on Carbon: MoO2 Epoxidation Catalyst Anchored to a Fullerene DOI Creative Commons
Amol Agarwal, Yiqi Liu, Olga A. Kraevaya

et al.

ChemCatChem, Journal Year: 2024, Volume and Issue: 16(23)

Published: Aug. 16, 2024

Abstract Single‐site molybdenum dioxo catalysts, fullerenol/MoO 2 , are prepared via grafting precursor (DME)MoO Cl onto a highly polyhydroxylated fullerene (ful) and an isomerically‐pure well‐defined (ful*). These catalyst structures characterized by ICP‐OES, XPS, XANES, EXAFS, DRIFT, Raman, NMR spectroscopy, DFT. Mo 3d 5/2 XPS K‐edge XANES assign the oxidation state as Mo(VI). EXAFS data fitting reveals two Mo=O double Mo−O single bonds at distances of 1.7 1.9 Å, respectively, while stretchingl mode is observed ~950 cm −1 DRIFT Raman spectroscopy. align well with DFT computational results, supporting proposed structure Fullerene(‐μ‐O‐) M(=O) . Additionally, provides insight into energetically favorable sites for isomerically pure fullerenol. The scope mediated alkene epoxidation includes abiotic alkenes, natural occurring terpenes, conjugated olefins. For cyclooctene rate law first‐order in [Mo], near first order [olefin] zero‐order [t‐butyl hydroperoxide]. A plausible reaction mechanism involves peroxide addition then directly across peroxo bond forming epoxide product, consistent computation. Overall, shows promise sustainable structurally system versatile catalytic activity good recyclability.

Language: Английский

Citations

1