Multifunctional approach to improve water oxidation performance with MOF-based photoelectrodes

Metal-Organic Frameworks (MOFs) are a group of compounds with high porosity and diverse capabilities in photoelectrochemistry. The use of these compounds as photocatalysts and photoelectrodes is still a strong challenge due to bulk and surface recombination issues. To solve this problem, we applied a dual strategy to simultaneously enhance charge separation and catalytic activity in MIL-125-NH2 and UIO-66-NH2 MOF photocatalysts. Mesoporous TiO2 was used as electron-selective contact on the MOF surface (MOF/TiO2) to minimize bulk recombination. On the other hand, to increase the MOF catalytic activity for water oxidation, a well-matched Co3(PO4)2 (CoPi) co-catalyst (CoPi/MOF/TiO2) was used. The obtained results showed that CoPi and TiO2 were introduced in the MOF structure. The (CoPi/MOF/TiO2) photoelectrodes showed a photocurrent density 26 times higher compared to the reference MOF at 1.23 V vs. RHE for PEC water oxidation of artificial seawater, validating the developed strategy for further photocatalytic and photoelectrochemical applications.Funding for open access charge: CRUE-Universitat Jaume IWe acknowledge with appreciation the financial support from the University of Isfahan and Ministry of Science, Research and Technology Center for International Scientific Studies and Collaboration (CISSC). SG acknowledges the financial support from the Ministerio de Ciencia, Innovación y Universidades of Spain through funded project ENE2017-85087-C3-1-R

SPION-A-Pd(EDTA) (superparamagnetic iron oxide nanoparticles-A-ethylendiamine tetraacetic acid) as a robust nanocatalyst for Buchwald-Hartwig C-N Coupling Reaction

During thelast20-30 years, palladium-catalyzed reactions have witnessed tremendous advances in the industrial and organic reactions such as hydrogenation, coupling, cyanation and amination. Despite the wide utility of Pd-catalysts in these reactions, they suffer from a number of drawbacks such as recovery, reuse of catalyst and remain as  a contaminant in the products at the end of the reaction. A powerful and convenient reaction procedure for the C-N coupling reaction (the Buchwld-Hartwig reaction), yielding products of N-arylanilines and N-arylamines in conventional heating has been reported. The protocol utilized an high stable Pd(EDTA)2- salt by counter cation of N-methylimidazolium bounded to 1,3,5-triazine-tethered SPIONs (superparamagnetic iron oxide nanoparticles). The reaction products were produced under conventional heating at extremely low catalyst loading (as low as 0.003 mol% Pd).Finally, we also examined the reusability of the catalyst.  It was found that the catalyst could be recovered by external magnetic field and be reused for five times without obvious loss in catalytic activity

Efficient buchwald hartwig reaction catalyzed by spions-bis(NHC)-Pd(II)

A powerful and convenient reaction procedure for the C-N coupling reaction (the Buchwald-Hartwig reaction), yielding products of N-arylanilines and N-arylamines in both conventional heating and microwave irradiation has been reported. The protocol utilizes a stable and new supper ferromagnetic nanoparticle chelating N-heterocyclic dicarbene palladium(II) complex (Pd-NHC) as catalyst which helps/allows us to complete the reaction with only 0.002 mol% Pd producing high yield products. We also examined the reusability of the catalyst. It was found that the catalyst could be recovered by external magnetic field and  reused for seven times without obvious loss in catalytic activity

Palladium nanoparticles immobilized on multifunctional ‎hyperbranched polyglycerol-grafted magnetic nanoparticles as a ‎sustainable and efficient catalyst for C-C coupling reactions

This study offers an exclusive class of magnetic nanoparticles supported hyperbranched polyglycerol (MNP/HPG) that was functionalized with citric acid (MNP/HPG-CA) as a host immobilization of palladium nanoparticles. The MNP/HPG-CA/Pd catalyst was fully characterized using some different techniques such as thermogravimetric analysis (TGA), x-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDX), inductively coupled plasma (ICP) and x-ray photoelectron spectroscopy (XPS). The new catalytic system showed high activity for the Suzuki–Miyaura cross-coupling and Heck reaction under mild and green conditions. Besides, the MNP/HPG-CA/Pd was found to be a convenient catalyst for copper-free Sonogashira coupling reaction in water as a green solvent at room temperature. Moreover, the catalyst could be recovered easily and reused several times without significant loss of reactivity. Ease of preparation, oxygen insensitive, phosphine-free, air- and moisture-stable, and high reusability of this immobilized palladium catalyst are the noteworthy advantages of this catalytic system

Copolymer‐templated nickel oxide for high‐efficiency mesoscopic perovskite solar cells in inverted architecture

Despite the outstanding role of mesoscopic structures on the efficiency and stability of perovskite solar cells (PSCs) in the regular (n–i–p) architecture, mesoscopic PSCs in inverted (p–i–n) architecture have rarely been reported. Herein, an efficient and stable mesoscopic NiOx (mp-NiOx) scaffold formed via a simple and low-cost triblock copolymer template-assisted strategy is employed, and this mp-NiOx film is utilized as a hole transport layer (HTL) in PSCs, for the first time. Promisingly, this approach allows the fabrication of homogenous, crack-free, and robust 150 nm thick mp-NiOx HTLs through a facile chemical approach. Such a high-quality templated mp-NiOx structure promotes the growth of the perovskite film yielding better surface coverage and enlarged grains. These desired structural and morphological features effectively translate into improved charge extraction, accelerated charge transportation, and suppressed trap-assisted recombination. Ultimately, a considerable efficiency of 20.2% is achieved with negligible hysteresis which is among the highest efficiencies for mp-NiOx based inverted PSCs so far. Moreover, mesoscopic devices indicate higher long-term stability under ambient conditions compared to planar devices. Overall, these results may set new benchmarks in terms of performance for mesoscopic inverted PSCs employing templated mp-NiOx films as highly efficient, stable, and easy fabricated HTLs

Bi(TFA)3 and Bi(OTf)3 Catalyzed Conversions of Epoxides to Thiiranes with Ammonium Thiocyanate and Thiourea under Non-Aqueous Conditions

Various epoxides are converted to their corresponding thiiranes in excellent yields with ammonium thiocyanate and thiourea under non-aqueous conditions in the presence of catalytic amounts of Bi(TFA)3 and Bi(OTf)3