Search

The construction of Z-scheme heterojunction composite catalysts for overall water splitting is promising. Herein, a triangle-shaped prismatic metal–organic cage MOC-Q3 consisting of two photosensitive ligands and three catalytic Pd2+ centers is synthesized as an intramolecular photocatalytic molecular device (IPMD) to conduct a photocatalytic light-to-fuel reaction. MOC-Q3 is then coupled with graphitic phase carbon nitride (g-C3N4) to form a composite catalyst by intermolecular π–π stacking through quasi-2D/2D contact. And the charge transfers at the MOC-Q3/g-C3N4 interface are proven to follow a Z-scheme pathway by radical trapping experiments and theoretical calculations. The optimized 11 wt% MOC-Q3/g-C3N4 catalyst exhibits a remarkable photocatalytic H2 evolution activity of 50.1 mmol h−1 g−1, one of the highest values reported among g-C3N4-based Z-scheme systems in recent years. And a high turnover number (TON) of 363 740 based on the MOC moles is achieved in a prolonged photocatalytic experiment lasting 32 h. Furthermore, the overall water splitting reaction was successfully conducted using MOC-Q3/g-C3N4 in combination with a classical water oxidation catalyst (WOC) IrO2, without the addition of any sacrificial agent, yielding H2 and O2 amounts of 400.7 and 200.5 μmol g−1 within 5 h, respectively. This study presents an inspiring approach of combining IPMDs and g-C3N4 to prepare highly efficient composite catalysts for visible light-driven H2 evolution and overall water splitting. [ABSTRACT FROM AUTHOR]

For this research, three hydrophobically modified polyacrylamides, HPAAB, HPAAF, and HPAAS, with multiple hydrophobic monomers were designed, synthesized, and used as thickeners in aqueous ink for digital ink-jet printing. The structures were characterized by Fourier transform infrared (FTIR) analysis and nuclear magnetic resonance (NMR) spectroscopy. The viscosity–average molecular weight was determined by intrinsic viscosity determination and was adjusted according to hydrophobic content. The critical association concentration (CAC) of polymers was measured simultaneously using the apparent viscosity method and the fluorescence spectrum. The formation of a network structure and the mechanism of hydrophobic association are visualized dynamically with a scanning electron microscope (SEM) at different concentrations. Under the same conditions, HPAAB exhibited excellent thickening ability across different pH levels, temperatures, and shear rates, which is caused by the longer hydrophobic side chain and the stronger hydrophobic effect of the behenyl polyoxyethylene ether methacrylate (BEM) group. Furthermore, an aqueous ink using HPAAB as a thickener displays significant printability and stability, functioning much better than a corresponding aqueous ink that uses a commercial thickener. This is the first example of a hydrophobic associating polyacrylamide, incorporating both hydrophilic and hydrophobic units within a single hydrophobic chain, thereby serving as an efficient thickener for aqueous ink. [ABSTRACT FROM AUTHOR]

Three cone-calix[4]arene-based sensitizers ( Calix-1- Calix-3) with multiple donor-π-acceptor ( D-π-A) moieties are designed, synthesized, and applied in dye-sensitized solar cells (DSSCs). Their photophysical and electrochemical properties are characterized by measuring UV/Vis absorption and emission spectra, cyclic voltammetry, and density functional theory (DFT) calculations. Calix-3 has excellent thermo- and photostability, as illustrated by thermogravimetric analysis (TGA) and dye-aging tests, respectively. Importantly, a DSSC using the Calix-3 dye displays a conversion efficiency of 5.48 % in under standard AM 1.5 Global solar illumination conditions, much better than corresponding DSSCs that use the rod-shaped dye M-3 with a single D-π-A chain (3.56 %). The dyes offer advantages in terms of higher molar extinction coefficients, longer electron lifetimes, better stability, and stronger binding ability to TiO2 film. This is the first example of calixarene-based sensitizers for efficient dye-sensitized solar cells. [ABSTRACT FROM AUTHOR]

Invited for the cover of this issue is the group of Jun-Min Liu and Cheng-Yong Su at Sun Yat-Sen University. The image shows that cone-calix[4]arene-based dye flowers can develop in the field of dye-sensitized solar cells as sunflowers thrive under sunshine. The Full Paper itself is available at [ABSTRACT FROM AUTHOR]

Metal-free photosensitizers for the construction of low-cost and eco-friendly dye-sensitized photoelectrochemical cells (DSPECs) have recently been greatly improved, but the optimization of water oxidation catalysts (WOCs) used in DSPECs based on metal-free dyes has received little attention. Herein, a series of polymer networks (RuTPA, RuCz, RuPr and RuTz) assembled by ruthenium WOCs (RuCHO) with various organic donors are constructed and combined with calixarene dyes to prepare DSPEC devices. The FTO|TiO 2 |C4BTP+RuTPA photoanode shows the best performance with 85 % Faraday efficiency for oxygen production and 477 μA cm -2 photocurrent density after 200 s chopping irradiation at 0 V vs. Ag/AgCl, one of the highest records among other reported dye-sensitized photoanodes. Compared to monomeric RuCHO, Ru-based polymers with lower Ru content have higher activity and stability due to their rapid electron transfer and anti-aggregation ability. Meanwhile, RuTPA loaded electrodes show better performance due to the lower overpotential of the water oxidation reaction caused by the higher electron donating ability of its donor. This pioneering work incorporates Ru polymer networks as WOCs into the calixarene-sensitized DSPEC system, which has significant potential as a highly efficient and stable photoelectrochemical water splitting device., (© 2024 Wiley-VCH GmbH.)

Sulfur hexafluoride (SF 6 ) is widely used as an insulating gas, being an etchant and contrast agent in the electrical, semiconductor, and medical industries. However, due to its long lifetime and high global warming potential in the atmosphere, SF 6 must be carefully handled to prevent leakage during production and usage. Herein, we report a sod-net metal-azolate framework (MAF) named MAF-stu-111, which decorates methyl and aldehyde groups in the porous windows, showing high adsorption affinity for SF 6 at low pressure. Stability tests, gas adsorption, and breakthrough experiments demonstrated that MAF-stu-111 possesses excellent water and chemical stability, fully reversible SF 6 uptake, high SF 6 /N 2 separation selectivity (10:90, 285.2), good reusability, and high SF 6 recovery purity (99.03%). Theoretical calculations revealed that hydrogen atoms of methyl and aldehyde groups can form multiple hydrogen bonds with SF 6 molecules, which ensure that SF 6 molecules are firmly held within the MAF-stu-111 framework, playing a key role in the selective separation of SF 6 /N 2 .