Nickel selenide/g-C3N4 heterojunction photocatalyst promotes CC coupling for photocatalytic CO2 reduction to ethane.

Photocatalytic CO2 reduction to generate high value-added and renewable chemicals is of great potential in facilitating the realization of closed-loop and carbon-neutral hydrogen economy. Stabilizing and accelerating the formation of COCO* intermediate is crucial to achieve high-selectivity ethane production. Herein, a novel 3D/2D NiSe2/g-C3N4 heterostructure that mesoscale hedgehog nickel selenide (NiSe2) grown on the ultrathin g-C3N4 nanosheets were synthesized via a successively high temperature calcination process and in-situ thermal injection method for the first time. The optimum 2.7 % NiSe2/g-C3N4 heterostructure achieved moderate C2H6 generation rate of 46.1 µmol·g-1·h-1 and selectivity of 97.5 % without any additional photosensitizers and sacrificial agents under light illumination. Based on the results of the theoretical calculations and experiments, the improvement of photocatalytic CO2 to C2H6 production and selectivity should be ascribed to the increased visible light absorption ability, unique 3D/2D heterostructures with promoted adsorption of CO2 molecules on the Ni active sites, the type II heterojunction with improved charge transfer dynamics and lowered interfacial transfer resistance, as well as the formation of COCO* key intermediate. This work provides an inspiration to construct efficient photocatalysts for the direct transformation of CO2 to multicarbon products (C2+).

Electrochemical and Capacitive Properties of Carbon Dots/Reduced Graphene Oxide Supercapacitors.

There is much recent interest in graphene-based composite electrode materials because of their excellent mechanical strengths, high electron mobilities, and large specific surface areas. These materials are good candidates for applications in supercapacitors. In this work, a new graphene-based electrode material for supercapacitors was fabricated by anchoring carbon dots (CDs) on reduced graphene oxide (rGO). The capacitive properties of electrodes in aqueous electrolytes were systematically studied by galvanostatic charge-discharge measurements, cyclic voltammetry, and electrochemical impedance spectroscopy. The capacitance of rGO was improved when an appropriate amount of CDs were added to the material. The CD/rGO electrode exhibited a good reversibility, excellent rate capability, fast charge transfer, and high specific capacitance in 1 M H2SO4. Its capacitance was as high as 211.9 F/g at a current density of 0.5 A/g. This capacitance was 74.3% higher than that of a pristine rGO electrode (121.6 F/g), and the capacitance of the CD/rGO electrode retained 92.8% of its original value after 1000 cycles at a CDs-to-rGO ratio of 5:1.

Hydrostatic pressure effects on the fluorescence and FRET behavior of Cy3-labeled phycocyanin system.

FRET has been used as a powerful tool in biological fields as biosensors, bioimaging, protein folding/unfolding monitoring, biomolecular interactions, and so on. It is also important to applying FRET to high hydrostatic pressure studies on biosystems or biorelated systems. Herein, we construct a FRET system by labeling Cy3 on C-phycocyanin (C-PC) to investigate the effect of hydrostatic pressure on the fluorescence and FRET behavior between them. The fluorescence spectra of individual Cy3, C-PC, and integrated Cy3/C-PC system are measured separately under compression. An enhanced FRET efficiency under compression is concluded based on fluorescence behavior differences between them. To further reveal the origination of the enhanced FRET efficiency with pressure, the overlap integral between Cy3 emission and C-PC absorption is also calculated, and several possible explanations are proposed.

Construction of a supramolecular Förster resonance energy transfer system and its application based on the interaction between Cy3-labeled melittin and phosphocholine encapsulated quantum dots.

Due to possessing unique optical properties, semiconductor quantum dots (QDs) have been applied to construct bioconjugates. Using QDs as donors, the Förster resonance energy transfer (FRET) system can be developed and applied to biological imaging and sensing, and various construction strategies have been reported. To provide a new practicable method, we introduce a protocol with two routes to construct a supramolecular FRET system based on the high-affinity interaction between melittin and phosphocholine. Melittin exists with a random coil structure in aqueous environments but will adopt a bent helix when inserted into natural or artificial membranes. Such specific and high affinity protein-membrane interaction makes it possible to construct a QDs-based FRET system. The strategy applying protein-membrane interaction to construct a QDs-based FRET system can be applied to the investigation on the protein-membrane interaction through distance-depended FRET and further proteolysis of trypsin. Because of the existence of various protein-membrane interactions in real life, the system has the potential to be expanded to other related systems.

Honeycomb micropatterning of proteins on polymer films through the inverse microemulsion approach.

Here we report the rapid and convenient patterning of proteins on porous polymer film using the inverse microemulsion approach. Following this method, proteins, which were dissolved in water, were transferred into dichloromethane solution of polymers through the formation of inverse microemulsion by mixing the two solutions. The protein-containing microemulsion droplets accumulated automatically into large and stable ones on the surface of organic solution casting on solid substrates, and formed tightly packed microemulsion droplet arrays driven by surface tension. With the evaporation of organic solvent and water, the microemulsion droplet arrays, which act as the template, turn to honeycomb patterned pores bearing proteins in them. The formed protein patterns can be locally applied for the detection of other proteins through specific recognition. The generality and reproducibility for the formation of BSA/PS microporous film and protein patterning by using different polymers and solvents were demonstrated by investigating surfactant addition, polymer and solvent types, and casting volume on the morphology of the microporous films. A preliminary mechanism for the protein patterning is discussed based on the analysis of the experimental results.

A unique protein labeling system based on melittin and the non-covalent binding-induced pyrene excimer.

We report a unique protein labeling system based on melittin and a pyrene derivative (1). The specific region of the C-terminal in melittin efficiently induced the formation of the pyrene eximer, which can be used as a tag to target proteins and for further detection.

An easily prepared hypersensitive water-soluble fluorescent probe for mercury(II) ions.

A hypersensitive water-soluble fluorescent probe, dansyl-L-tryptophan methyl ester (1), was easily prepared for the detection of Hg(2+) with a significantly improved detection limit (5 nM vs. 500 nM) in buffered aqueous solution.

Selective detection of trace Cr3+ in aqueous solution by using 5,5'-dithiobis (2-nitrobenzoic acid)-modified gold nanoparticles.

A simply prepared gold nanoparticle-based sensor, 5,5'-dithiobis (2-nitrobenzoic acid) (DTNBA)-modified gold nanoparticles, was prepared to explore the sensitive and selective detection of metal ions using a colorimetric technique. The selective detection of trace levels (93.6 ppb) Cr3+ in aqueous solution was achieved over 15 other metal ions. The functionalized gold nanoparticles became aggregated in solution in the presence of Cr3+ by an ion-templated chelation process, which caused an easily measurable change in the extinction spectrum of the particles and provided an inherently sensitive method for Cr3+ detection in aqueous solution.