Isolating Single Sn Atoms in CuO Mesocrystal to Form Ordered Atomic Interfaces: An Effective Strategy for Designing Highly Efficient Mesocrystal Catalysts

Tuning the electronic structures of mesocrystals at the atomic level is an effective approach to obtaining unprecedented properties. Here, a lattice-confined strategy to obtain isolated single-site Sn atoms in CuO mesocrystals to improve catalytic performance is reported. The Sn/CuO mesocrystal composite (Sn/CuO MC) has ordered Sn-O-Cu atomic interfaces originated from the long-range ordering of the CuO mesocrystal itself. X-ray absorption fine structure measurements confirm that the positively charged Sn atoms can tune the electronic structure of the Cu atoms to some extent in Sn/CuO MC, quite different from that in the conventional single-atom Sn-modified CuO nanoparticles and nanoparticulate SnO₂ -modified CuO mesocrystal catalysts. When tested for the Si hydrochlorination reaction to produce trichlorosilane, Sn/CuO MC exhibits significantly better performances than the above two catalysts. Theoretical calculations further reveal the electronic modification to the active Cu component and the induced improvement in HCl adsorption, and thus enhance the catalytic performance. This work demonstrates how to design efficient metal oxide mesocrystal catalysts through an electronic structure modification approach.

Non-Enzymatic Glucose Sensors Involving Copper: An Electrochemical Perspective

Non-enzymatic glucose sensors based on the use of copper and its oxides have emerged as promising candidates to replace enzymatic glucose sensors owing to their stability, ease of fabrication, and superior sensitivity. This review explains the theories of the mechanism of glucose oxidation on copper transition metal electrodes. It also presents an overview on the development of among the best non-enzymatic copper-based glucose sensors in the past 10 years. A brief description of methods, interesting findings, and important performance parameters are provided to inspire the reader and researcher to create new improvements in sensor design. Finally, several important considerations that pertain to the nano-structuring of the electrode surface is provided.

Hierarchically porous CuO spindle-like nanosheets grown on a carbon cloth for sensitive non-enzymatic glucose sensoring

Herein, porous CuO spindle-like nanosheets were fabricated on a carbon cloth using a facile hydrothermal method, and surface morphology, microstructure, and glucose sensing performance were studied. The porous spindle-like nanosheets are constructed by nanoparticles and slit-like pores, exhibiting a hierarchical structure. When used for non-enzymatic glucose sensoring, the obtained CuO nanosheet electrode exhibits a wide linear range from 0.05 to 3.30 mM, a high sensitivity of 785.2 μA mM^-1 cm^-2 and a low detection limit of 0.22 μM (S/N = 3). Besides, good selectivity, stability, and reproducibility for glucose detection indicate a promising application of CuO nanosheet electrodes as non-enzymatic glucose sensors.

Fabrication of WO2/W@C core-shell nanospheres for voltammetric simultaneous determination of thymine and cytosine

Pomegranate-like multicore WO₂/W nanocrystals wrapped with layers of multiporous carbon were fabricated via carbonization of a copper(II)-organic framework host and a tungsten-based polyoxometalates guest, and subsequent etching off the metallic copper. The WO₂/W@C core-shell nanospheres were employed to modify an electrode for the analysis of the DNA bases thymine (T) and cytosine (C) by differential pulse voltammetry. The WO₂/W@C exhibited strongly increased oxidation signal of T and C. Under optimized conditions, the enhanced peak current represented excellent analytical performance for determination of T and C. This is attributed to the synergic effects of the porous multicore-shell microstructure and the use of tungsten-based materials with their excellent electrocatalytic activity for T and C, with typical peaks voltages near 1.26 V and 1.44 V. The calibration plots for T and C extend from 1 to 4000 μM and from 1 to 3000 μM, respectively, and both detection limits are 0.2 μM. The method was successfully applied to the determination of T and C in spiked blood and urine samples, and the recoveries are form 97.3 to 105.0%. Graphic abstractCore-shell nanospheres of type WO2/W-carbon were prepared for highly sensitive simultaneous voltammetric determination of thymine and cytosine.

Multiporous molybdenum carbide nanosphere as a new charming electrode material for highly sensitive simultaneous detection of guanine and adenine

By introduction of Mo metal species (molybdenum-based polyoxometalates) into the Cu-MOF as co-precursor, molybdenum carbide nanosphere (Mo_xC@C) was prepared via a simple calcining routine and a further etching the metallic Cu process. The obtained Mo_xC@C showed a unique structure where well-dispersed Mo_xC nanoparticles (NPs) were encapsulated in porous carbon matrix. As-fabricated novel 3D porous architecture Mo_xC@C nanosphere exhibited a potent and persistent electro-oxidation behavior followed by well-separated oxidation peaks (peak to peak voltage is about 350 mV) toward adenine (A) and guanine (G) by differential pulse voltammetry (DPV). This excellent electrochemical performance can be attributed to the unique structure and composition of 3D Mo_xC@C. Furthermore, 3D Mo_xC@C also revealed high selectivity and sensitivity, good reproducibility, excellent stability and anti-interference ability. The calibration curves for quantitive analysis of G and A were obtained: 0.03-122 µM, and 0.02-122 µM, respectively, the detection limits were 0.0085 µM, 0.008 µM, respectively. The proposed procedure was successfully applied to detect G and A in human urine and serum samples with satisfactory recovery, which manifests its viability application for practical analysis.

One-step synthesis of novel Cu@polymer nanocomposites through a self-activated route and their application as nonenzymatic glucose sensors

Novel core–shell Cu@polymer nanocomposites were synthesized through a one-step self-activated route and developed as nonenzymatic glucose sensor.