Photoelectrochemical properties of bare fluorine doped tin oxide and its electrocatalysis and photoelectrocatalysis toward cysteine oxidation

A Dual-emitting Two-dimensional Nickel-based Metal-organic Framework Nanosheets: Eu3+/Ag+ Functionalization Synthesis and Ratiometric Sensing in Aqueous Solution

Using two-dimensional (2D) nickel-based metal organic framework (Ni-MOF) nanosheets as a matrix, Eu³⁺ and Ag⁺ were incorporated to synthesize Ag/Eu@Ni-MOF with double luminescence centers of Eu³⁺ ion (615 nm) and organic ligand (524 nm). And a ratiometric luminescence sensor is constructed based on Ag/Eu@Ni-MOF for sensitive detection of biothiols in aqueous solutions. The dual-emissive fluorescence properties can be tuned by changing the amounts of Ag⁺ ions doping. The results of temperature and pH effects on the fluorescence of Ag/Eu@Ni-MOF indicates that the Ag/Eu@Ni-MOF is a temperature-sensitive material and the fluorescence of Ag/Eu@Ni-MOF can keep stable over a wide pH range. Due to the binding of -SH in cysteine (Cys) and glutathione (GSH) with Ag⁺, the ligand luminescence was significantly inhibited by weakening the Ag + influence on the energy transfer process in the MOFs. Therefore, ratiometric fluorescent sensing of biomolecular thiols was realized based on the dual-emission Ag/Eu@Ni-MOF. More importantly, the fluorescence color change can be observed with naked eyes to realize visual detection. The ratiometric fluorescent sensor exhibits high performance for Cys and GSH detection with a wide linear range of 5-250 µM and a relatively low detection limit of 0.20 µM and 0.17 µM, respectively. Furthermore, the biothiols content in human serum was determined with satisfactory results. It proves the Ni-MOF nanosheets can be used as a stable matrix for construction luminescent MOFs for the first time, and validate the great potential of Ag/Eu@Ni-MOF as a ratiometric fluorescent probe for point-of-care testing (POCT) in disease diagnosis.

What Fluorine Can Do in CO2 Chemistry: Applications from Homogeneous to Heterogeneous Systems

CO₂ chemistry including capture and fixation has attracted great attention towards the aim of reducing the consumption of fossil fuels and CO₂ accumulation in the atmosphere. "CO₂ -philic" materials are required to achieve good performance owing to the intrinsic properties of the CO₂ molecule, that is, thermodynamic stability and kinetic inertness. In this respect, fluorinated materials have been deployed in CO₂ capture (physical and chemical pathway) or fixation (thermo- and electrocatalytic procedure) with good performances, including homogeneous (e. g., ionic liquids and small organic molecules) and heterogeneous counterparts (e. g., carbons, porous organic polymers, covalent triazine frameworks, metal-organic frameworks, and membranes). In this Minireview, these works are summarized and analyzed from the aspects of (1) the strategy used for fluorine introduction, (2) characterization of the targeted materials, (3) performance of the fluorinated systems in CO₂ chemistry, and comparison with the nonfluorinated counterparts, (4) the role of fluorinated functionalities in the working procedure, and (5) the relationship between performance and structural/electronic properties of the materials. The systematic summary in this Minireview will open new opportunities in guiding the design of "CO₂ -philic" materials and pave the way to stimulate further progress in this field.

A dual mode photoelectrochemical sensor for nitrobenzene and L-cysteine based on 3D flower-like Cu2SnS3@SnS2 double interfacial heterojunction photoelectrode

In this work, 3D hierarchical Cu₂SnS₃@SnS₂ flower assembled from nanopetals with sandwich-like Cu₂SnS₃-SnS₂-Cu₂SnS₃ double interfacial heterojunction was successfully designed and synthesized on fluoride doped tin oxide (FTO) for photoelectrochemical (PEC) sensor by in situ electrodeposition p-type Cu₂SnS₃ nanoparticles on both inner and outer surfaces of n-type SnS₂ nanopetals. The unique double interfacial heterojunction simultaneously combines 3D flower-like architectures to drastically increase the light trapping and absorption in visible-near infrared range (Vis-NIR), and dramatically inhibites the charge carrier recombination, which is crucial for boosting the PEC activity. Benefitting from the shape and compositional merits, the Cu₂SnS₃@SnS₂ heterojunction possess dual-mode signal by controlling the electrodeposition time to manipulate the composition ratio of Cu₂SnS₃ and SnS₂. The Cu₂SnS₃@SnS₂/FTO electrode not only exhibits excellent photoeletro-reduction capacity for ultra-sensitive sensing trace persistent organic pollutant (nitrobenzene, NB), but also presents photoeletro-oxidization activity for high selective detection of L-cysteine (L-Cys) without any auxiliary enzyme under the light illumination. Dual mode sensor displayed superb performance for the detection of NB/L-Cys, showing a wide linear range from 100 pM to 300 μM/10 nM to 100 μM and a low detection limit (3S/N) of 68 pM/8.5 nM, respectively. Such a tunable double interfacial heterojunction design opened up new avenue for constructing multifunction PEC sensing platform.

Tin oxide nanostructured materials: an overview of recent developments in synthesis, modifications and potential applications

Various structural modifications of tin oxide nanostructures leading to multidimensional applications.