Multifunctional and Ultrastable Co-MOF Effectively Separates Various Different Component Gas Mixtures.

Developing low-cost and multifunctional adsorbents for adsorption separation to obtain high-purity (>99.9%) gases is intriguing yet challenging. Notably, the ongoing trade-off between adsorption capacity and selectivity in separating multicomponent mixed gases still persists as a pressing scientific challenge requiring urgent attention. Herein, the ultrastable TJT-100 exhibits unique structural characteristics including uncoordinated carboxylate oxygen atoms, coordinated water molecules directed toward the pore surface, and sufficient Me2NH2+ cations in channels. TJT-100 exhibits a high adsorption capacity and exceptional separation performance, particularly notable for its high C2H2 capacity of 127.7 cm3/g and remarkable C2H2 selectivity over CO2 (5.4) and CH4 (19.8), which makes it a standout material for various separation applications. In a breakthrough experiment with a C2H2/CO2 mixture (v/v = 50/50), TJT-100 achieved a record-high C2H2 productivity of 69.33 L/kg with a purity of 99.9%. Additionally, TJT-100 demonstrates its effectiveness in separating CO2 from natural gas and flue gas. Its exceptional selectivity for CO2/CH4 (10.7) and CO2/N2 (11.9) results in a high CO2 productivity of 21.23 and 22.93 L/kg with 99.9% purity from CO2/CH4 (v/v = 50/50) and CO2/N2 (v/v = 15/85) mixtures, respectively.

Enhancing Photoreduction of Cr(VI) through a Multivalent Manganese(II)-Organic Framework Incorporating Anthracene Moieties.

Exploiting a photocatalyst with high stability and excellent activity for Cr(VI) reduction under mild conditions is crucial yet challenging. Herein, the rigid aromatic multicarboxylate ligand with chromophore anthracene was selected to coordinate with multivalent metal ion manganese and to obtain a stable two-dimensional (2D) Mn-based metal-organic framework (MOF), LCUH-120, which can efficiently and quickly convert Cr(VI) into Cr(III) under light without the need for any additional photosensitizer. The efficient photosensitive anthracene group serves as a photosensitizer center and multivalent Mn(II) ion as a photocatalyst center in LCUH-120, and the conversion of Cr(VI) to Cr(III) can be realized completely in just 40 min. Specifically, the rate constant (k) and reduction rate of the Cr(VI) photocatalytic reaction can be high up to 0.134 min-1 and 2.50 mgCr(VI) g-1cata min-1 in an acidic environment (pH = 2), respectively. Compared to our previously reported three-dimensional (3D) Sm-MOF, LCUH-120 exhibits a significantly higher catalytic reaction rate, which might be ascribed to the fact that the photocatalyst center Mn node can improve the rate of electron transfer and promote the separation of holes and photogenerated electrons. In an acidic environment, the reaction mechanism can be verified through various contrast experiments and theoretical simulations.

Functionalized 2D defect g-C3N4 for artificial photosynthesis of H2O2 and synchronizing tetracycline fluorescence detection and degradation.

Artificial photosynthesis of H2O2 is a clean production technology, which brings the synergistic effect to photodegradation of pollutants. Inspired by defect engineering, 2D defective carbon nitride (g-C3N4) photocatalyst was obtained via potassium ion assisted synthesis. Defective g-C3N4 is protonated and applied to photosynthesis of H2O2, H2O2 concentration produced reached 477.7 µM, which was approximately 5.27 times that by pristine g-C3N4. Additionally, defective g-C3N4 materials are borrowed to synchronizing tetracycline (TC) fluorescence detection and degradation, suggesting the catalyst existed bifunctional characteristics of TC detection and degradation. Meanwhile, metal impregnation engineering (molybdenum) was borrowed enhancing the electron-trapping ability in local region of defective g-C3N4, which takes advantages to the efficient degradation of TC. Furthermore, optical and electrical properties of photocatalysts were investigated in details by advanced material characterization testing. This work provides potential applications in the field of artificial photosynthesis and pollution degradation.

Constructing interface engineering and tailoring a nanoflower-like FeP/CoP heterostructure for enhanced oxygen evolution reaction.

The inexpensive and highly efficient electrocatalysts toward oxygen evolution reaction (OER) in water splitting electrolysis have displayed promising practical applications to relieve energy crisis. Herein, we prepared a high-yield and structurally regulated bimetallic cobalt-iron phosphide electrocatalyst by a facile one-pot hydrothermal reaction and subsequent low-temperature phosphating treatment. The tailoring of nanoscale morphology was achieved by varying the input ratio and phosphating temperature. Thus, an optimized FeP/CoP-1-350 sample with the ultra-thin nanosheets assembled into a nanoflower-like structure was obtained. FeP/CoP-1-350 heterostructure displayed remarkable activity toward the OER with a low overpotential of 276 mV at a current density of 10 mA cm-2, and a low Tafel slope of only 37.71 mV dec-1. Long-lasting durability and stability were maintained with the current with almost no obvious fluctuation. The enhanced OER activity was attributed to the presence of copious active sites from the ultra-thin nanosheets, the interface between CoP and FeP components, and the synergistic effect of Fe-Co elements in the FeP/CoP heterostructure. This study provides a feasible strategy to fabricate highly efficient and cost-effective bimetallic phosphide electrocatalysts.

In situ construction of 0D CoWO4 modified 1D Mn0.47Cd0.53S for boosted visible-light photocatalytic H2 activity and photostability.

To enhance the photocatalytic activity, loading proper semiconductor with high efficiency and low cost is one of the most valid approaches. Herein, various amounts of CoWO4 as a novel metal-free material were loaded on Mn0.47Cd0.53S (MCS) nanorods for photocatalytic hydrogen production reaction. The CoWO4/Mn0.47Cd0.53S-25 (CW/MCS-25) exhibits the highest hydrogen production rate of 41.53 mmol·h-1·g-1 in the Na2S/Na2SO3 system, which is about 2.68 times higher than that of pristine MCS. The Mapping and HRTEM reveals the deposited of CoWO4 on the MCS. The detailed analyses of XPS, EIS, TRPL spectra and transient photocurrent responses indicate that CoWO4 and MCS interacted closely and the photogenerated electrons of CoWO4 can be transferred into MCS. In particular, the introduction of CoWO4 can further transfer the photogenerated holes of MCS, thereby inhibiting the photocorrosion of MCS and improving photocatalytic activity. This work provides a reference for the exploration of noble metal-free composite material and shows great potential in the photocatalytic application.

A novel octanuclear nickel(II)-molybdenum(VI) heterometallic cluster based on the salicylhydroxamate ligand.

Salicylhydroxamic acid (H3shi) is known for its strong coordination ability and multiple coordination modes, and can easily coordinate to metal cations to form compounds with five- or six-membered rings, as well as mono-, di- and multinuclear compounds with interesting structures having potential applications in organic chemistry, coordination chemistry, and the materials and biological sciences. A novel octanuclear nickel(II)-molybdenum(VI) heterometallic cluster based on the salicylhydroxamate ligand, namely di-µ3-acetato-di-µ2-acetato-di-µ3-hydroxido-di-µ3-oxido-tetraoxidooctakis(pyridine-κN)bis(µ5-salicylhydroxamato)hexanickel(II)dimolybdenum(VI) monohydrate, [Mo2Ni6(C7H4NO3)2(C2H3O2)4O5(OH)2(C5H5N)8]·H2O, (I), was synthesized by the reaction of sodium molybdate, nickel acetate and salicylhydroxamic acid in a dimethylformamide/pyridine/methanol solution at room temperature. The salicylhydroxamate(3-) (shi(3-)), acetate and oxide ligands adopt complicated coordination modes and link six Ni(II) and two Mo(VI) cations into the octanuclear heterometallic cluster. All of the metal cations exhibit octahedral coordination geometries and are connected to each other through the sharing of corners, edges or planes. The heterometallic clusters are further connected to form two-dimensional supramolecular layers through weak C-H...O hydrogen bonds. Studies of the magnetic properties of the title compound reveal antiferromagnetic interactions between the Ni(II) cations.

A special coupling strategy: Cu2MoS4 as a large-sized co-catalyst for promoting photocatalytic hydrogen production performance.

The photocatalytic hydrogen production performance of semiconductor materials can be improved by co-catalyst modification. In most of the studies, the size of the co-catalyst is relatively small compared to the primary catalyst. However, in this study, we employed a novel strategy by synthesizing a relatively large-sized Cu2MoS4 as the co-catalyst and in situ loading smaller-sized Zn0.5Cd0.5S onto Cu2MoS4, verifying that Cu2MoS4 enhances the photocatalytic hydrogen production efficiency of Zn0.5Cd0.5S. It can be observed by scanning electron microscopy (SEM) that the lateral size of 2D Cu2MoS4 is at least 50 times larger than the Zn0.5Cd0.5S nanoparticle particle size. In addition, Density Functional Theory (DFT) calculations have demonstrated that the active site for hydrogen production in the composite is located in Cu2MoS4. The large-sized of Cu2MoS4 not only provides more active sites but also broadens the electron transport channel, which is conducive to promoting the transfer of photogenerated electrons from Zn0.5Cd0.5S. This work enriches the study of large-sized materials as co-catalyst and provides a strategy for the construction of composite catalysts.