Thermal Post-Treatments to Enhance the Water Stability of NH2-MIL-125(Ti)

Gómez-Avilés, Almudena; Muelas-Ramos, Virginia; Bedia, Jorge; Rodrı́guez, Juan J.; Belver, Carolina

doi:10.3390/catal10060603

Cited by 35 publications

(12 citation statements)

References 55 publications

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“…The N 2 adsorption–desorption isotherms of MIL-125-NH 2 , HCl/MIL-125-NH 2 , and RuO 2 /MIL-125-NH 2 samples (1) and (2) (Figure a) showed an overall type II behavior, following the International Union of Pure and Applied Chemistry classification. This behavior has been reported already for MIL-15-NH 2 and is in line with its microporous character. , At the same time, different behaviors for the two RuO 2 /MIL-125-NH 2 samples and the HCl/MIL-125-NH 2 sample in contrast to the pristine MIL-125-NH 2 at higher pressures were observed. The appearance of a small hysteresis between the adsorption and desorption traces for these three samples is consistent with the presence of mesopores in increasing magnitudes along the series HCl/MIL-125-NH 2 < RuO 2 /MIL-125-NH 2 (1) < (2).…”

Section: Resultssupporting

confidence: 76%

Hierarchical Ti-Based MOF with Embedded RuO₂ Nanoparticles: a Highly Efficient Photoelectrode for Visible Light Water Oxidation

Afzali

Tangestaninejad

Keshavarzi

et al. 2020

ACS Sustainable Chem. Eng.

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The Ti-based metal−organic framework (MOF) MIL-125-NH 2 is one of the promising materials for solar water splitting because it contains a sensitizer and a catalytic center in a single structure. MIL-125-NH 2 as many other MOFs has a microporous structure with pore diameters less than 2 nm. Compared with common MOFs, hierarchical mesoporous materials exhibit very large specific surface areas that facilitate diffusion of active species, accelerate subsequent surface reactions, and increase the bubble release rate by providing larger free spaces. Thus, the development of a facile method to create hierarchical porous MOFs with larger pore sizes remains a chemical challenge. Furthermore, MOF-type semiconducting materials usually have low activities in oxygen evolution reaction, and the presence of a suitable cocatalyst is needed to reduce the large O 2 overpotential. This study attempted to generate a hierarchical MIL-125-NH 2 MOF material with embedded RuO 2 nanoparticles as a highly efficient cocatalyst in a simple one-step process for use in efficient solar water oxidation. Different amounts of RuCl 3 •H 2 O precursor salt were used simultaneously for creating hierarchical porosity in MIL-125-NH 2 and for producing the assumed RuO 2 cocatalyst. For comparison, a hydrochloric acid treatment was applied to generate hierarchical porosity in the MOF in the absence of ruthenium. The samples were characterized using high-resolution transmission electron microscopy (HRTEM), Brunauer−Emmett−Teller adsorption, powder X-ray diffraction, field emission scanning electron microscopy, and X-ray photoelectron spectroscopy. HRTEM gave evidence that in the ruthenium oxidecontaining MIL-125-NH 2 samples, tetragonal RuO 2 nanoparticles are present. The materials were applied as photoelectrodes, and photoelectrochemical (PEC) water oxidation performance under visible light illumination was studied. The PEC water oxidation performance of the MIL-125-NH 2 layer could be strikingly improved with a photocurrent density of about 10 times more than that of the pure MOF at 1.23 V versus reversible hydrogen electrode in artificial seawater, as a result of the hierarchical MOF structure and the presence of RuO 2 as a cocatalyst. Furthermore, density functional theory calculations were performed to shed light on the electronic properties and the role of the RuO 2 in the assumed hole transport.

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Section: Resultssupporting

confidence: 76%

Hierarchical Ti-Based MOF with Embedded RuO₂ Nanoparticles: a Highly Efficient Photoelectrode for Visible Light Water Oxidation

Afzali

Tangestaninejad

Keshavarzi

et al. 2020

ACS Sustainable Chem. Eng.

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“…On note, our Al-PMOF(Fe) photocatalyst is superior to NH 2 -MIL-125(Ti) in terms of stability. A recent study demonstrated that NH 2 -MIL-125(Ti) would easily leach out and experience framework degradation in water, thus losing reusability as a photocatalyst. In contrast, our Al-PMOF(Fe) exhibits good hydrolytic stability thanks to the robust aluminum metal cluster nodes in NRR, thereby imparting high reusability of Al-PMOF(Fe) as a photocatalyst, which will be discussed below.…”

Section: Results and Discussionmentioning

confidence: 99%

Atomically Dispersed Iron Metal Site in a Porphyrin-Based Metal–Organic Framework for Photocatalytic Nitrogen Fixation

et al. 2021

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The rational design of photocatalysts for efficient nitrogen (N 2 ) fixation at ambient conditions is important for revolutionizing ammonia production and quite challenging because the great difficulty lies in the adsorption and activation of the inert N 2 . Inspired by a biological molecule, chlorophyll, featuring a porphyrin structure as the photosensitizer and enzyme nitrogenase featuring an iron (Fe) atom as a favorable binding site for N 2 via π-backbonding, here we developed a porphyrin-based metal−organic framework (PMOF) with Fe as the active center as an artificial photocatalyst for N 2 reduction reaction (NRR) under ambient conditions. The PMOF features aluminum (Al) as metal node imparting high stability and Fe incorporated and atomically dispersed by residing at each porphyrin ring promoting the adsorption and the activation of N 2 , termed Al-PMOF(Fe). Compared with the pristine Al-PMOF, Al-PMOF(Fe) exhibits a substantial enhancement in NH 3 yield (635 μg g −1 cat. ) and production rate (127 μg h −1 g −1 cat. ) of 82% and 50%, respectively, on par with the best-performing MOF-based NRR catalysts. Three cycles of photocatalytic NRR experimental results corroborate a stable photocatalytic activity of Al-PMOF(Fe). The combined experimental and theoretical results reveal that the Fe−N site in Al-PMOF(Fe) is the active photocatalytic center that can mitigate the difficulty of the rate-determining step in photocatalytic NRR. The possible reaction pathways of NRR on Al-PMOF(Fe) were established. Our study of porphyrin-based MOF for the photocatalytic NRR will provide insight into the rational design of catalysts for artificial photosynthesis.

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“…434 to its instability under the optimized experimental conditions. 434,435 In any case, considering any possible commercial implementation of MOFs, it is important to assess the long-term photostability under solar light and outdoor conditions, determining the main reasons for photocatalytic activity decay and devising doable reactivation methods.…”

Section: Photocatalyst Stabilitymentioning

confidence: 99%

Metal–Organic Frameworks as Photocatalysts for Solar-Driven Overall Water Splitting

et al. 2022

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Metal–organic frameworks (MOFs) have been frequently used as photocatalysts for the hydrogen evolution reaction (HER) using sacrificial agents with UV–vis or visible light irradiation. The aim of the present review is to summarize the use of MOFs as solar-driven photocatalysts targeting to overcome the current efficiency limitations in overall water splitting (OWS). Initially, the fundamentals of the photocatalytic OWS under solar irradiation are presented. Then, the different strategies that can be implemented on MOFs to adapt them for solar photocatalysis for OWS are discussed in detail. Later, the most active MOFs reported until now for the solar-driven HER and/or oxygen evolution reaction (OER) are critically commented. These studies are taken as precedents for the discussion of the existing studies on the use of MOFs as photocatalysts for the OWS under visible or sunlight irradiation. The requirements to be met to use MOFs at large scale for the solar-driven OWS are also discussed. The last section of this review provides a summary of the current state of the field and comments on future prospects that could bring MOFs closer to commercial application.

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Thermal Post-Treatments to Enhance the Water Stability of NH2-MIL-125(Ti)

Cited by 35 publications

References 55 publications

Hierarchical Ti-Based MOF with Embedded RuO₂ Nanoparticles: a Highly Efficient Photoelectrode for Visible Light Water Oxidation

Hierarchical Ti-Based MOF with Embedded RuO₂ Nanoparticles: a Highly Efficient Photoelectrode for Visible Light Water Oxidation

Atomically Dispersed Iron Metal Site in a Porphyrin-Based Metal–Organic Framework for Photocatalytic Nitrogen Fixation

Metal–Organic Frameworks as Photocatalysts for Solar-Driven Overall Water Splitting

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Thermal Post-Treatments to Enhance the Water Stability of NH2-MIL-125(Ti)

Cited by 35 publications

References 55 publications

Hierarchical Ti-Based MOF with Embedded RuO2 Nanoparticles: a Highly Efficient Photoelectrode for Visible Light Water Oxidation

Hierarchical Ti-Based MOF with Embedded RuO2 Nanoparticles: a Highly Efficient Photoelectrode for Visible Light Water Oxidation

Atomically Dispersed Iron Metal Site in a Porphyrin-Based Metal–Organic Framework for Photocatalytic Nitrogen Fixation

Metal–Organic Frameworks as Photocatalysts for Solar-Driven Overall Water Splitting

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Product

Resources

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Hierarchical Ti-Based MOF with Embedded RuO₂ Nanoparticles: a Highly Efficient Photoelectrode for Visible Light Water Oxidation

Hierarchical Ti-Based MOF with Embedded RuO₂ Nanoparticles: a Highly Efficient Photoelectrode for Visible Light Water Oxidation