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A sulfur-mediated photodeposition method is used to accurate modulate NiS cocatalyst at photoelectron transfer sites of BiVO4, which markedly boosts photocatalytic activity of interfacial O2 reduction to H2O2 for BiVO4.

Detection mechanism and effect of SSAPA for Tb3+ and ATP detection.

A lucigenin and riboflavin chemiluminescence system was utilized for the first to achieve “turn-on” detection of tyrosinase activity via the in situ generation of dopamine.

An electrochemiluminescence (ECL) dual “turn-on” strategy is first designed to detect alkaline phosphatase (ALP) using a dual quenching Ru(bpy)32+ encapsulated zeolite imidazole metal organic framework (Ru(bpy)32+@ZIF-90).

Although intensive efforts have been made and great progress has been achieved relating to the electrocatalytic hydrogen evolution reaction (HER), an advanced synthesis strategy for an efficient electrocatalyst is still the most significant goal. In this paper, we introduce PdFeCoNiCu high-entropy alloy (HEA) nanoparticles as an efficient electrocatalyst for the HER, which has been prepared in an oil phase under facile conditions for the first time. PdFeCoNiCu/C shows excellent alkaline HER catalytic performance with an overpotential of only 18 mV and a Tafel slope of 39 mV dec−1. Meanwhile, we achieved the highest mass activity (6.51 A mgPd−1 at −0.07 V vs. RHE) in the alkaline HER among all non-Pt electrocatalysts. PdFeCoNiCu/C also shows surprisingly stable catalytic properties for over 15 days without notable decay. Based on theoretical calculations, the HEA surface demonstrates the optimization of electronic structures based on a synergistic effect between all metals. Pd and Co are confirmed to be the dominant electroactive sites for both H2 formation and initial water splitting, which are assisted by Ni, Fe, and Cu promotion, enhancing electron transfer and optimizing the binding energies of hydrogen intermediates. This work has supplied significant insight into the design of an efficient electrocatalyst based on HEA materials.

A fluorescent probe with high selectivity for the detection of copper ions (Cu2+) is synthesized using 4-hydroxyhypoxidone, paraformaldehyde and proline via a one-step Mannich reaction. This Cu2+ fluorescent probe with large Stokes shift (129 nm) has good water solubility and could coordinate with Cu2+. It achieves fluorescence of this probe to be quenched linearly with the increasing concentration of Cu2+ from 10 to 800 nM. Since Cu2+ and pyrophosphate (PPi) have a stronger coordination ability, it promotes Cu2+ to coordinate with PPi preferentially and results in the fluorescence of the system being enhanced again. In this way, a novel fluorescence “turn-on” detection of PPi in the range from 2 to 40 μM within 2 min is developed using this Cu2+ fluorescent probe. It exhibits high selectivity in PPi detection towards other anions such as Cl−, NO3−, CO32−, PO43− and SO42−. It is worth noting that PPi can be hydrolyzed into phosphate (Pi) by alkaline phosphatase (ALP), and the coordination between Cu2+ and Pi is not as strong as that with the probe. Herein the fluorescence of the system can be quenched again after the addition of ALP. A fluorescence “turn-off” detection of ALP from 10 to 90 mU L−1 is achieved using this Cu2+ fluorescent probe. When it is used to detect ALP in serum samples, recoveries from 98.5% to 104.2% are obtained.

Herein, highly efficient electrochemiluminescence (ECL) of novel Au–Ag bimetallic nanocluster @CNTs–TiO2 nanocomposites (Au–Ag NCs@CNTs–TiO2 NPs) with a unique “pearl necklace” structure was achieved. An ECL immunosensor was fabricated for simple, label-free and ultra-sensitive detection of cancer embryo antigen (CEA). The functionalized CNTs–TiO2 was used as a light-emitting carrier of Au–Ag NCs, TiO2 NPs were used as the co-reaction accelerator and dissolved O2 as the intrinsic co-reactant for the in situ generation of the strong oxidizing intermediate radical OH˙. OH˙ significantly influenced the ECL properties of metal NCs. Carbon nanotubes (CNTs) acted as conductors, enabling faster electron transfer and more effective energy transmission in the Au–Ag NCs@CNTs–TiO2 NP nanostructure. Compared with the ECL of pure Ag NCs, the ECL of Au–Ag NCs on the TiO2 NP surface was significantly enhanced due to the synergistic effect of bimetallic NCs. The experimental results showed that Au–Ag NCs@CNTs–TiO2 NPs achieved excellent ECL performance, and decreased the detection limit of the immunosensor for measuring CEA to 0.03 pg mL−1 in the absence of any additional signal amplification assay. The proposed ECL immunosensor is expected to be promising for applications in diagnostics and bioanalysis using other biomolecules.

A one-pot approach has been demonstrated for the synthesis of amorphous luminol–gallium (Ga) nanoassemblies, which are formed by small particles with big irregular spheres or network nanoassemblies. Moreover, luminol–Ga nanoassemblies exhibit peroxidase-mimetic activity toward the oxidation of peroxidase substrate 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H2O2) owing to its stimulating effect on the formation of reactive oxygen groups, such as hydroxyl radicals (OH˙). After the addition of luminol–Ga nanoassemblies to the TMB–H2O2 system, a remarkable color change is observed from colorless TMB to its blue product TMBox accompanied by an absorption peak at around 652 nm. Owing to the presence of reactive oxygen groups by luminol–Ga nanoassemblies, the peroxidase-mimetic activity is inhibited by PPi. Accordingly, the blue color fades away and the absorbance at 652 nm is decreased. Herein a novel sensitive colorimetric detection of PPi from 0.5 to 15 μM using luminol–Ga nanoassemblies is developed with the limit of detection (LOD) of 62.4 nM. The practicability of the assay toward the detection of PPi is also investigated in real water analysis such as lake water and tap water. Recoveries from 97.3% to 102.6% in local lake water and tap water samples are obtained. Therefore this cost-effective peroxidase-based analysis using luminol–Ga nanoassemblies is a potentially powerful tool for the quantitative determination of PPi in environmental samples.

The electrochemical N2 reduction reaction (NRR) under ambient conditions is highly attractive. However, it is still a challenge to achieve a high NH3 yield rate at low overpotential. Herein, we report RuO2 nanoparticles with different degrees of surface selenation, which show excellent NRR performance at low overpotential. The NH3 yield rate and FE of RuO2–Se0.18/C reach 12.97 μg h−1 cm−2 and 26.01% at −0.1 V vs. RHE, respectively, which is the highest NH3 yield rate reported at low overpotential. The RuO2–Se0.18/C catalyst also shows excellent stability. The related NH3 yield rate stays pretty constant after 50 h of electrolysis. The density functional theory (DFT) calculations show multiple promoted-synergism of surface selenation on the RuO2 catalyst. First, optimized surface selenization could drive the adsorption of N2 on RuO2 sites. Second, surface hydrogenation promoted by surface selenization can suppress the hydrogen evolution reaction (HER, competitive reaction), enabling high NRR performance at low potential. Third, optimizing the surface selenization on RuO2 can promote N2 activation (*N2 → *NNH). Fourth, surface selenization can promote NH3 desorption (the rate-limiting step).

Herein, the electrochemiluminescence (ECL) donor Ru(bpy)32+-doped silica nanoparticles (RuSiNPs) and acceptor methylene blue (MB) were combined to achieve electrochemiluminescence resonance energy transfer (ECRET) using the overlap of the ECL emission of RuSiNPs with the absorption of MB. Owing to the ECRET from RuSiNPs to MB, the ECL of RuSiNPs was quenched by MB. During the oxidation of glucose catalysed by MB only under an alkaline condition, MB with blue color is reduced to the colourless form methylene white by glucose; this is accompanied by the disappearance of absorbance at 650 nm. Accordingly, ECRET was inhibited after the addition of glucose to the RuSiNP and MB mixture. Therefore, the ECL “turn-on” detection of glucose was achieved via the proposed ECRET strategy. The proposed ECRET method exhibited high sensitivity for glucose detection with the limit of detection (LOD) of 85.4 nM, selectivity towards glucose in the presene of metal ions, anions, dopamine or uric acid, and fast response within 5 min; moreover, it was successfully applied for glucose detection in human serum samples, and the average recoveries of 99.33%, 99.73% and 100.07% were obtained. This widens the application of ECRET in bioanalysis.

An ultrasensitive sandwich-type electrochemiluminescent (ECL) immunosensor suitable for identifying carcinoembryonic antigens (CEAs) was developed, using a metal–organic framework nanomaterial (AuNP@NPCGO) as an ideal loading platform and Ru(phen)32+-doped silica nanoparticles (RuSiNPs) as ECL signaling units. The AuNP@NPCGO nanocomposites were synthesized via in situ deposition of AuNPs on NPCGO as this configuration exhibits high conductivity, strong fixed ability, and excellent stability. The use of RuSiNPs as signaling units provided numerous luminophores that enhanced the ECL signals. Besides the aminated RuSiNPs, which had a large specific surface area and good biocompatibility, functioned as a superior matrix for immobilizing numerous secondary antibodies (Ab2). The proposed ECL immunosensor demonstrated excellent performance for CEA detection at concentrations of 0.01 ng mL−1 to 80 ng mL−1 with a detection limit of 0.003 ng mL−1 at a signal-to-noise ratio of three.

Fe3O4@3-aminophenol–formaldehyde (Fe3O4@APF) core–shell resin polymer magnetic nanocomposites were synthesized using a straightforward surfactant-free methodology. The shell quickly formed within 5 min and could be easily size tunable in the range from 15 to 137 nm by changing the concentrations of 3-aminophenol and formaldehyde. The morphology, composition and magnetic properties of the resulting magnetic microspheres were characterized by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis measurements. The magnetic microspheres were uniform in morphology and can be converted into Fe3O4@carbon magnetic nanocomposites because of their excellent thermal stability. Moreover, Fe3O4@APF magnetic microspheres have excelling adsorption properties in the removal of methyl blue.

Luminol electrochemiluminescence is dramatically increased by about five hundred times by taking full advantage of both electrochemical reduction and electrochemical oxidation using simple linear sweep voltammetry, leading to sensitive detection.

A fluorescence resonance energy transfer (FRET) platform for the detection of ozone was developed by combining the overlap of the fluorescence spectrum of Ru(bpy)3(2+)-doped silica nanoparticles with the absorption spectrum of indigo carmine at around 600 nm. This FRET system can be used to detect ozone simply within 10 min. Simple qualitative ozone detection methods using cotton swabs or paper were also developed.