Frustrated Lewis Pairs Boosting Low-Temperature CO₂ Methanation Performance over Ni/CeO₂ Nanocatalysts

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(17), P. 10587 - 10602

Published: Aug. 15, 2022

Deciphering the relationship between active-site structure and CO2 methanation mechanism over Ni-based catalysts faces great challenges. Herein, different distributions of frustrated Lewis pair (FLP) structures were precisely fabricated Ni/CeO2-nanorods, Ni/CeO2-nanocubes, Ni/CeO2-nanooctahedra to make progress in this issue. Ni/CeO2-nanorods presented highest possibility for FLP construction among these due their CeO2 (110) nature steric hindrance oxygen vacancy (OV) hydroxyl species (OH). Compared other samples with fewer FLPs, FLPs-enriched showed a significantly higher conversion (84.2%) CH4 productivity up 147.1 mmol gcat–1 h–1 selectivity (97.8%) even at temperature as low 225 °C. As evidenced from systematical ex situ surface analysis results, better low-temperature activity along its acceptable stability was closely associated catalytically active which could effectively activate convert via cooperation OV OH. Also, (Raman diffuse-reflectance infrared Fourier transform spectroscopy) combined density functional theory calculations further demonstrated that copromotion emerged CO* route formate pathway responsible promising (≤225 °C) performance FLP-enriched Ni/CeO2-nanorods. Such activation by FLPs will potentially guide design hydrogenation catalysts.

Language: Английский

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Elucidation of Active Sites for CH₄ Catalytic Oxidation over Pd/CeO₂ Via Tailoring Metal–Support Interactions

ACS Catalysis, Journal Year: 2021, Volume and Issue: 11(9), P. 5666 - 5677

Published: April 26, 2021

Pd/CeO2 has attracted great attention owing to its unique activity for methane catalytic oxidation; however, the active sites CH4 oxidation still remain elusive, which affects comprehensive understanding of mechanism. In this work, structures PdOx nanoparticles (NPs) loaded on octahedrons, cubes, and rods nanocrystal CeO2 supports were systematically studied by Cs-corrected HRTEM/STEM, XPS, Raman spectroscopy. Our results indicate that Pd species are morphology-dependent: PdO NPs (Pd2+) (x = 1–2) clusters (1–2 nm) dispersed Pd4+ ions rods. Additionally, chemical states can be tuned in oxidizing/reducing atmospheres via interactions between CeO2. Detailed studies reveal Pd2+ centers methane. The Pd0 could ascribed produced through gradual during oxidation. Further, lattice is inactive situ Fourier transform infrared spectroscopy suggest mechanism reaction PdOx/CeO2 follows Mars–van Krevelen mechanism, adsorbed CO decomposition over absence gas-phase oxygen. As revealed density functional theory calculations, incomplete coordination adjacent oxygen atoms excellent cracking C–H bond CH4, leads high ability.

Language: Английский

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Interfacial Polarization Loss Improvement Induced by the Hollow Engineering of Necklace‐like PAN/Carbon Nanofibers for Boosted Microwave Absorption

Advanced Functional Materials, Journal Year: 2024, Volume and Issue: unknown

Published: Feb. 28, 2024

Abstract Rational manipulation of composition and microstructure design is recognized as an effective pathway to realize multifunctional high‐performance microwave absorber. In this work, necklace‐like hollow polyacrylonitrile (PAN)/carbon nanofibers are designed constructed through a simple continuous electrospinning‐carbonization‐etching route. Specifically, by varying the carbonization temperature, ratio PAN carbon content PAN/carbon can be effectively regulated, resulting in tunable electromagnetic parameters conductive loss capacities. After that, structure further introduced improve feature lightweight, impedance‐matching characteristics, interfacial polarization ability. Accordingly, exhibited frequency bandwidth 6.60 GHz minimum reflection −44.73 dB at 1.76 mm. Both experimental theoretical simulation results indicated that obtained possessed high chemical stability excellent absorbing performance, endowing them candidates for absorbers extreme conditions. Therefore, findings not only offered rationally manipulate but also provided novel technique make most engineering strengthening interface loss.

Language: Английский

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Construction of CuO/CeO₂ Catalysts via the Ceria Shape Effect for Selective Catalytic Oxidation of Ammonia

ACS Catalysis, Journal Year: 2023, Volume and Issue: 13(2), P. 1077 - 1088

Published: Jan. 2, 2023

Tuning the interaction between loaded metal oxide and support material is an efficient strategy to boost catalytic purification of ammonia (NH3) as important factor in formation haze. Herein, CuO/CeO2 catalysts based on ceria shape effect (Ce-NR Ce-NC) are prepared tested for selective oxidation (NH3-SCO). The CuO CeO2 with different shapes crucial regulate interface structure content oxygen vacancies. Cu/Ce-NR possesses more Cu+-Ov-Ce3+ interfacial sites vacancies achieves a higher activity (T100 = 240 °C) lower apparent activation energy (37.18 kJ mol–1) NH3-SCO compared Cu/Ce-NC 270 °C, 86.57 mol–1). In situ diffuse reflectance infrared Fourier transform spectra density functional theory calculation results prove that site main adsorption NH3. further reaction generated nitrate NH3 rate-determining step over catalysts, it revealed much easily reacts monodentate species formed catalyst than bidentate at °C. This study enriches understanding designing by modulate their thus improve NH3-SCO.

Language: Английский

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Oxygen vacancies in the catalyst: Efficient degradation of gaseous pollutants

Chemical Engineering Journal, Journal Year: 2022, Volume and Issue: 454, P. 140376 - 140376

Published: Nov. 15, 2022

Language: Английский

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Investigation into the catalytic roles of oxygen vacancies during gaseous styrene degradation process via CeO2 catalysts with four different morphologies

Applied Catalysis B Environment and Energy, Journal Year: 2022, Volume and Issue: 309, P. 121249 - 121249

Published: Feb. 24, 2022

Language: Английский

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CeO2 supported Pd dimers boosting CO2 hydrogenation to ethanol

Applied Catalysis B Environment and Energy, Journal Year: 2021, Volume and Issue: 291, P. 120122 - 120122

Published: March 10, 2021

Language: Английский

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Reinforcing self-assembly of hole transport molecules for stable inverted perovskite solar cells

Science, Journal Year: 2024, Volume and Issue: 383(6688), P. 1236 - 1240

Published: March 14, 2024

Power conversion efficiencies (PCEs) of inverted perovskite solar cells (PSCs) have been improved by the use a self-assembled monolayer (SAM) hole transport layer. Long-term stability PSCs requires keeping SAM compact under layer during operation. We found that strong polar solvents in precursor desorb if it is anchored on substrates hydrogen-bonded, rather than covalently bonded, hydroxyl groups. used atomic-layer deposition to create an indium tin oxide substrate with fully covalent hydroxyl-covered surface for anchoring, as well trimethoxysilane group exhibited tridentate anchoring substrate. The resulting achieved PCEs 24.8 (certified 24.6) and 23.2% aperture areas 0.08 1.01 square centimeters, respectively. devices retained 98.9 98.2% initial PCE after 1000 hours damp-heat test operation maximum power point tracking at 85°C 1200 standard illumination,

Language: Английский

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Ti‐doped CeO₂ Stabilized Single‐Atom Rhodium Catalyst for Selective and Stable CO₂ Hydrogenation to Ethanol

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(44)

Published: Sept. 9, 2022

Development of effective and stable catalysts for CO2 hydrogenation into ethanol remains a challenge. Herein, we report that Rh1 /CeTiOx single-atom catalyst constructed by embedding monoatomic Rh onto Ti-doped CeO2 support has shown super high selectivity (≈99.1 %), record-breaking turnover frequency (493.1 h-1 ), outstanding stability. Synergistic effects Ti-doption contribute to this excellent catalytic performance firstly facilitating oxygen vacancies formation generate oxygen-vacancy-Rh Lewis-acid-base pairs, which favor adsorption activation, cleavage C-O bonds in CHx OH* COOH* * CO* species, subsequent C-C coupling ethanol, secondly generating strong Rh-O bond Ti-doping-induced crystal reconstruction, contributes striking This work highlights the importance elaborating regulation design substantially improve performance.

Language: Английский

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Insights into the Influence of ZrO₂ Crystal Structures on Methyl Laurate Hydrogenation over Co/ZrO₂ Catalysts

ACS Catalysis, Journal Year: 2021, Volume and Issue: 11(12), P. 7099 - 7113

Published: June 2, 2021

Six kinds of ZrO2 supports (ZRX, X = 1–6) with different crystal structures (monoclinic ZrO2: m-ZrO2; tetragonal t-ZrO2; and mixed-phase monoclinic mix-ZrO2) were synthesized, their effects on the properties Co/ZrO2 catalysts investigated for methyl laurate hydrogenation. Among prepared catalysts, Co/mix-ZrO2 (Co/ZR3), highest concentration surface Co2+, oxygen vacancies (Ov), complex types exposed Co planes, exhibited activity stability toward hydrogenation, nearly 100% yield liquid alkanes produced at 240 °C, or 90.5% fatty alcohol (selectivity: 96%) 180 °C. By exploring reaction kinetics catalyst properties, in support found to play an important role tuning valence state Co, while structure influenced lattice planes cobalt. The high Ov content active β-Co(102) face Co/ZR3 efficient reducing activation energies C–C C═O bond cleavage, causing ester Less-active such as α-Co(111) α-Co(200), made intermediate difficult be deoxygenated alkanes.

Language: Английский

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