Preparation of hierarchically structured Y zeolite with low Si/Al ratio and its applications in acetalization reactions

Jiao, Wen Qian; Fu, Wenhua; Liang, Xiao; Wang, Yi Meng; He, Min

doi:10.1039/c4ra11042k

Cited by 48 publications

(41 citation statements)

References 51 publications

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“…22,34 In order to dissolve the Na-form of X and Y zeolites, severe conditions are required, e.g. 21,22,35 Firstly, it is important to state that by steaming dealumination of the framework is attained whereas the bulk Si/Al ratio is unchanged. 22 Although the zeolitic properties of the resulting solids are fully preserved, the dissolution appears mostly unselective, resulting in a low mesopore efficiency (1 m 2 g À1 % À1 ).…”

Section: Desilication Of Dealuminated Crystalsmentioning

confidence: 99%

“…22,35 As shown in Section 2.2.1, an optimized treatment alone can render faujasites with well-developed and functional mesoporosity. 22,35 As shown in Section 2.2.1, an optimized treatment alone can render faujasites with well-developed and functional mesoporosity.…”

Section: Desilication Of Dealuminated Crystalsmentioning

confidence: 99%

“…22,35 As shown in Section 2.2.1, an optimized treatment alone can render faujasites with well-developed and functional mesoporosity. 22,23,35 Importantly, base treatment on Al-rich zeolites gives rise to substantial realumination of the external surface. Moreover, unlike its steamed analogue, this alkaline treatment does not strongly amorphize the sample.…”

Section: Desilication Of Dealuminated Crystalsmentioning

confidence: 99%

“…23 Similarly, acid treatment of Y zeolites gives rise to pronounced Si/Al gradients inside the crystals, yielding Al-rich and Al-depleted zones. 23,35 Hence, the mechanism of mesopore formation by base treatment of acid-treated Y zeolites should be distinctly different compared to the mesopore formation in highly-siliceous USY zeolites. 12d).…”

Section: View Article Onlinementioning

confidence: 99%

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Synthesis, characterisation, and catalytic evaluation of hierarchical faujasite zeolites: milestones, challenges, and future directions

et al. 2016

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Faujasite (X, Y, and USY) zeolites represent one of the most widely-applied and abundant catalysts and sorbents in the chemical industry. In the last 5 years substantial progress was made in the synthesis, characterisation, and catalytic exploitation of hierarchically-structured variants of these zeolites. Hererin, we provide an overview of these contributions, highlighting the main advancements regarding the evaluation of the nature and functionality of introduced secondary porosity. The novelty, efficiency, versatility, and sustainability of the reported bottom-up and (predominately) top-down strategies are discussed. The crucial role of the relative stability of faujasites in aqueous media is highlighted. The interplay between the physico-chemical properties of the hierarchical zeolites and their use in petrochemical and biomass-related catalytic processes is assessed.

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Section: Desilication Of Dealuminated Crystalsmentioning

confidence: 99%

Section: Desilication Of Dealuminated Crystalsmentioning

confidence: 99%

Section: Desilication Of Dealuminated Crystalsmentioning

confidence: 99%

Section: View Article Onlinementioning

confidence: 99%

See 2 more Smart Citations

Synthesis, characterisation, and catalytic evaluation of hierarchical faujasite zeolites: milestones, challenges, and future directions

et al. 2016

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“…13). 91 It is notable that after the acid (i.e., lactic acid) treatment, the peaks of Si(nAl, n = 2 -4) species decrease along with the increase of the Si(nAl, n = 0 and 1) peaks, suggesting the occurrence of dealumination in the Al-rich framework of the zeolite. The extracted Al ions are more likely to form aluminum lactate species which dissolve into the solution instead of remaining as extra-framework Al species in the zeolite structures.…”

Section: Surfactant-templated Zeolitesmentioning

confidence: 97%

Mesostructured zeolites: bridging the gap between zeolites and MCM-41

et al. 2015

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Surfactant-templating is one of the most versatile and useful techniques to implement mesoporous systems into solid materials. Various strategies based on various interactions between surfactants and solid precursors have been explored to produce new structures. Zeolites are invaluable as size-and shape-selective solid acid catalysts. Nevertheless, their micropores impose limitations on the mass transport of bulky feed and/or product molecules. Many studies have attempted to address this by utilizing surfactant-assisting technology to alleviate the diffusion constraints. However, most efforts have failed due to micro/ mesopore phase separation. Recently, a new technique combining the uses of cationic surfactants and mild basic solutions was introduced to synthesise mesostructured zeolites. These materials sustain the unique characteristics of zeolites (i.e., strong acidity, crystallinity, microporosity, and hydrothermal stability), including tunable mesopore sizes and degrees of mesoporosity. The mesostructured zeolites are now commercially available through Rive Technology, and show superior performance in VGO cracking. This feature article provides an overview of recent explorations in the introduction of mesoporosity into zeolites using surfactant-templating techniques. Various porous materials, preparation methods, physical and catalytic properties of mesostructured zeolites will be discussed.

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Optimizing Surface Composition and Structure of FeWO₄ Photoanodes for Enhanced Water Photooxidation

Nguyen

Bui

et al. 2023

Adv Materials Technologies

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Photoelectrochemical water splitting is a promising approach to produce green hydrogen using solar energy. A primary bottleneck remains the lack of efficient photoanodes to catalyze the sluggish water photooxidation reaction. Engineering photoabsorbers with a narrow bandgap and suitable band edge can boost the photoelectrochemical performance. Herein, nanostructured iron tungstate (FeWO4) photoanodes are engineered directly on a fluorine doped tin oxide glass substrate via a scalable and ultra‐fast flame synthesis route in 13 seconds. Physiochemical, optoelectronic, and electrochemical properties of these photoanodes are systematically investigated. The key roles of charge transport, transfer, and dissolution of W and Fe ions from the FeWO4 matrix within long‐term performance are revealed. Optimal FeWO4 photoanode with a bandgap of 1.82 eV and a FeOOH/NiOOH co‐catalyst coating shows an improved water photooxidation performance, reaching a photocurrent density of 0.23 mA cm−2 at 1.4 V versus reversible hydrogen electrode in 1 m potassium hydroxide. It further demonstrates relatively good photostability, maintaining ≈96% of photocurrent density after 1‐hour continuous photooxidation, albeit some trace of Fe, W and Ni elements dissolution. Insights on the photooxidation performance of nanostructured FeWO4 provide promising directions for the engineering of small band‐gap catalysts for a variety of photoelectrochemical applications.

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Preparation of hierarchically structured Y zeolite with low Si/Al ratio and its applications in acetalization reactions

Abstract: Hierarchically structured Y zeolites were prepared by a post-synthetic strategy, where the as-made NaY zeolite was sequentially treated by a lactic acid solution and an alkaline solution containing cetyltrimethyl ammonium bromide (CTAB).

Cited by 48 publications

References 51 publications

Synthesis, characterisation, and catalytic evaluation of hierarchical faujasite zeolites: milestones, challenges, and future directions

Synthesis, characterisation, and catalytic evaluation of hierarchical faujasite zeolites: milestones, challenges, and future directions

Mesostructured zeolites: bridging the gap between zeolites and MCM-41

Optimizing Surface Composition and Structure of FeWO₄ Photoanodes for Enhanced Water Photooxidation

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Preparation of hierarchically structured Y zeolite with low Si/Al ratio and its applications in acetalization reactions

Abstract: Hierarchically structured Y zeolites were prepared by a post-synthetic strategy, where the as-made NaY zeolite was sequentially treated by a lactic acid solution and an alkaline solution containing cetyltrimethyl ammonium bromide (CTAB).

Cited by 48 publications

References 51 publications

Synthesis, characterisation, and catalytic evaluation of hierarchical faujasite zeolites: milestones, challenges, and future directions

Synthesis, characterisation, and catalytic evaluation of hierarchical faujasite zeolites: milestones, challenges, and future directions

Mesostructured zeolites: bridging the gap between zeolites and MCM-41

Optimizing Surface Composition and Structure of FeWO4 Photoanodes for Enhanced Water Photooxidation

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Product

Resources

About

Optimizing Surface Composition and Structure of FeWO₄ Photoanodes for Enhanced Water Photooxidation