Zhelin Liu

PdCu alloy nanospheres with hollow interiors and rough surfaces were employed as electrocatalysts for the oxygen reduction reaction and alcohol oxidation reaction, exhibiting excellent performance.

A P ₂ W ₁₈ -assisted photoreduction method was proposed to fabricate the rGO-supported P ₂ W ₁₈ and PdPt alloy nanoparticles, which showed excellent electrocatalytic performance towards methanol, ethanol, and glycerol oxidation.

A PB@CD/SiO₂ composite can switch between fluorescence “ON” and “OFF” states, achieving the detection of hydrazine and hydrogen peroxide.

As a new type of artificial enzyme, a nanozyme is an ideal substitute for natural enzymes and has been successfully applied in many fields. However, in the application of biomolecular detection, most nanozymes have the disadvantages of long reaction times or high detection limits, prompting researchers to search for new efficient nanozymes. In this work, the enzyme-like activities of three polyoxometalate-based iron-organic complexes ([Fe(bpp)₂](Mo₆O₁₉), [Fe(bpp)₂]₂(Mo₈O₂₆)·2CH₃OH, and [Fe(bpp)₂]₄H[Na(Mo₈O₂₆)]₃), namely, FeMo₆, Fe₂Mo₈, and Fe₄Mo₈Na, were analyzed. All three polyoxometalate-based iron-organic complexes were found to be capable of catalyzing hydrogen peroxide (H₂O₂) to oxidize 3,3′,5,5′-tetramethylbenzidine and o-phenylenediamine, resulting in visible color changes, further exhibiting peroxidase-like activity. Results showed that Fe₄Mo₈Na had more active sites due to its long chain structure, endowing more prominent peroxidase-like activity compared with Fe₂Mo₈ and FeMo₆. A colorimetric sensing platform for H₂O₂ and ascorbic acid detection based on Fe₄Mo₈Na was established. The linear response range for H₂O₂ detection was 0.5–100 μM, and the detection limit was 0.143 μM. The linear response for ascorbic acid detection ranges from 0 to 750 μM with a detection limit of 1.07 μM. This study provides a new perspective for developing new nanozymes and expanding the sensing and detection application of nanozymes. Graphical abstract

Raspberry-like Pd₃Pb nanoparticles are prepared and employed as electrocatalyst towards ethylene glycol and glycerol oxidation.

Herein, a fluorescence “turn ON-OFF” switch model [email protected]/SiO2 [email protected] composite is designed and fabricated by coating EuW10-containing silica layer on the Prussian blue (PB) nanoparticles via a facile method. It is found that the presence of PB can quench the photoluminescence of the composite which arises from EuW10. When hydrazine is mixed with the composite dispersion, PB can be reduced to Prussian white (PW), resulting in the decrease of UV absorption and the appearance of photoluminescence (turn ON). In addition, PW can also be converted back to PB, which is achieved by adding hydrogen peroxide, and the photoluminescence of the composite is quenched again (turn OFF). Thus, the composite is applied for N2H4 and H2O2 detection by fluorescence spectroscopy and UV-vis absorption spectroscopy. Wide linear ranges for N2H4 and H2O2 detection with low detection limits are found for both detection methods on the [email protected]/SiO2 [email protected] composite. Besides, the color from light blue to colorless of the detection dispersion can also indicate the “turn ON-OFF” switch for fluorescence. Furthermore, the proposed model can also be extended for other composites.

Herein, Ni-MOF sheet incorporated with polypyrrole is fabricated via a simple wet-chemical approach, and the obtained PPy-MOF composite is investigated as an electrode material for supercapacitors. The composite is systematically investigated by a series of characterization studies including X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. Besides that, the electrochemical capacitive behaviors of the products are examined by electrochemical measurements. Electrochemical results show varying the ingredient ratio can lead to different electrocapacitive behavior, and PPy-MOF-0.2 is proved to possess the best performance in the investigated recipes. Furthermore, an asymmetric supercapacitor employing PPy-MOF and activated carbon as positive and negative electrodes is also assembled, which exhibits high energy density.