Direct observation of highly effective hydrogen isotope separation at active metal sites by in situ DRIFT spectroscopy.

In situ diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy was developed for the first time to observe the hydrogen isotope separation behavior at active CuI sites within CuI-MFU-4l, and clear evidence of the preferential adsorption of D2 over H2 was directly captured. More importantly, our results show direct spectral proof to clarify the chemical affinity quantum sieving mechanism of hydrogen isotope separation within porous adsorbents.

The ratiometric detection of the biomarker Ap5A for dry eye disease and physiological temperature using a rare trinuclear lanthanide metal-organic framework.

Urgent demand for the prevention and diagnosis of physiological diseases is driving the development of biomarkers and physiological temperature fluorometric sensors. In this paper, a rare trinuclear lanthanide metal-organic framework (MOF), [(CH3)2NH2][Eu3(µ3-OH)(2,6-NDC)3(HCOO)3]·(solv)x (Eu(2,6-NDC), where 2,6-H2NDC = 2,6-naphthalenedicarboxylic acid) was synthesized using reticular chemistry via reducing the symmetry of the organic ligand from axisymmetric 1,4-naphthalenedicarboxylic acid (1,4-H2NDC) to non-axisymmetric 2,6-H2NDC. Eu(2,6-NDC) shows exceptional chemical and thermal stability in acid-base solutions, PBS solution, and boiling water, and even under an air atmosphere up to 300 °C. As-synthesized Eu(2,6-NDC) exhibits ratiometric detection abilities for P1,P5-di(adenosine-5') pentaphosphate (Ap5A), for use as a biomarker of dry eye disease, with a limit of detection (LOD) of 0.031 µM, as well as excellent anti-interference properties. As far as is known, it is the first Ap5A sensor based on MOFs. In addition, the results show that the ratiometric parameters of co-doped Eu0.001Gd0.999(2,6-NDC) deliver a good linear luminescence response to physiological temperatures (20-60 °C) with high sensitivity.

Tailoring the triplet level of isomorphic Eu/Tb mixed MOFs for sensitive temperature sensing.

Three different thermo-responsive fluorescent thermometers were constructed by regulating the triplet energy level of organic ligands in isostructural Eu/Tb mixed MOFs. Among them, a quite unusual and rarely reported temperature-dependent fluorescence behavior was observed in LnBDC-NH2, and Eu0.01Tb0.99NDC is effective in the physiological range with the maximum relative sensitivity of 7.32% °C-1.

Platinum Single Atoms Supported on Nanoarray-Structured Nitrogen-Doped Graphite Foil with Enhanced Catalytic Performance for Hydrogen Evolution Reaction.

Platinum-based single-atom catalysts (SACs) are among the most promising candidates for the practical applications of electrochemical hydrogen evolution reaction (HER), but their catalytic efficiency remains to be further enhanced. Herein, a well-designed nanoarray-structured nitrogen-doped graphite foil (NNGF) substrate is introduced to support Pt SACs in Pt-N4 construction (Pt1/NNGF) for HER. Within NNGF, the constructed nanoarray-structured surficial layer for supporting Pt SACs could enhance the exposure of active sites to the electrolyte and improve the reaction and diffusion kinetics; meanwhile, the retained graphite structures in bulk NNGF provide not only the required electrical conductivity but also the mechanical stability and flexibility. Because of such double-layer structures of NNGF, stable Pt-N4 construction, and binder-free advantages, the Pt1/NNGF electrode exhibits a low overpotential of 0.023 V at 10 mA cm-2 and a small Tafel slope of 29.1 mV dec-1 as well as an excellent long-term durability.

Separation and characterization of the active species in Ti-doped NaAlH4.

The catalytic mechanism of doped complex hydrides for hydrogen storage remains unconfirmed. Here, we report a simple method to separate the active species of Ti-based catalysts in NaAlH(4) by filtration using tetrahydrofuran (THF) as solvent. The results show that the average particle size of the obtained Al-Ti active species is 30-50 nm.