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Nanosized materials acting as substitutes of natural enzymes are currently attracting significant research due to their stable enzyme-like characteristics, but some flaws of these nanozymes, including their limited catalytic rate and efficiency, need to be remedied to enable their wider applications. In this work, we verify for the first time the catalytic behavior of uncapped nanobranch-based CuS clews as a peroxidase mimic. XRD, XPS, SEM, and TEM proofs demonstrate that high-purity CuS clews composed of intertwined wires with abundant nanodendrites outside are successfully produced via a facile one-pot hydrothermal synthesis approach, with thiourea as both the sulfion source and the structure-directing agent. The synthesized CuS can catalytically oxidize 3,3',5,5'-tetramethylbenzidine (TMB) by H 2 O 2 to trigger a visible color reaction with rapid response (reaching a maximum change within 5 min). The proposed CuS nanozyme exhibits preferable catalytic kinetics over natural horseradish peroxidase (HRP). This outstanding activity primarily results from the large surface area and rich sites exposed by the uncapped unique structure. Under optimized conditions, the fabricated sensing system provides linear absorbance (652 nm) changes in the H 2 O 2 concentration range of 0.2˜130 μM, with a detection limit of as low as 63 nM. When coupled with glucose oxidase (GOD), the system is demonstrated to be capable of monitoring glucose in blood samples with excellent performance., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Enzyme-free electrochemical detection of glucose in alkaline media with favorable properties has been acquired by fabricating a robust and large-surface sensing platform, which is composed of anneal-shrinked Cu 2 O dendrites grown on porous Cu foam. On the one hand, the good compatibility of electrodeposited Cu 2 O architectures and Cu foam substrate, together with a post-deposition anneal at 200°C, offers a mechanically stable interface for glucose determination. On the other hand, the macropores of Cu foam that is decorated with unique Cu 2 O dendrites provide large active surface for electrocatalytic reaction and mass transport. As a result, selective sensing of glucose in the linear concentration range of 0.001-1.4mM was achieved on the fabricated sensor, with a sensitivity of as high as 5.04mAcm -2 mM -1 and a detection limit of 0.13μM. Desired long-term performance stability was obtained, partially due to the strong adhesion of Cu 2 O microstructures to the Cu foam support after annealing. Practical monitoring of glucose in serum samples was also demonstrated on the proposed sensor., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Abstract: The performance of electrochemical sensors is mainly limited by the intrinsic properties of electrocatalysts fabricated on the electrode. Introducing a p‐n heterojunction into semiconducing electrocatalysts is an effective strategy to enhance the sensing performance. In this paper, p‐n‐heterojunction‐based CuO/CeO2 nanocomposites were synthesized by a simple hydrothermal process, and the effect of different Cu/Ce molar ratios was explored. p‐CuO/n‐CeO2 was found to exhibit higher conductivity and electrocatalytic activity toward the target superoxide anion (O2.−) when compared to both bare CuO and CeO2. Characterization shows that different Cu/Ce ratios in p‐CuO/n‐CeO2 materials result in a considerable variation in the Ce3+/Ce4+ level, and energy band gap of CeO2, greatly affecting the electrochemical performance of p‐CuO/n‐CeO2. Under optimized conditions, these sensors exhibit high sensitivity and low detection limit toward O2.−. These results demonstrate that the performance of semiconductor‐based electrochemical sensors may be enhanced by the electron‐transfer process of p‐n junction interfaces. [ABSTRACT FROM AUTHOR]

Whereas metal-organic frameworks (MOFs) are being widely explored in the application of electrocatalysis, the electro-inert organic ligands in MOFs have negative effects on electron transfer. Here, we suggest a facile electrochemical cathodization treatment for the controllable evolution of a Cu-MOF to improve its electrocatalytic performance. When a cathodic potential was applied, Cu-based structures evolving from Cu-MOF with different crystal phases, surface compositions, and morphologies were harvested by controlling the cathodization time. The obtained copper-based structures were found to have much higher activities than the as-synthesized Cu-MOF for glucose electrocatalysis in alkaline media. A 60 second cathodization treatment resulted in the largest sensitivity for glucose electrocatalytic sensing. [ABSTRACT FROM AUTHOR]

In this work, we applied metal-organic frameworks (MOFs) as a porous matrix to encapsulate Cu nanoparticles (NPs) for nonenzymatic glucose sensing in alkaline media. SEM and TEM confirmed that the size of the encapsulated Cu NPs ranges from 2.5 to 5 nm. The hybrid of Cu NPs encapsulated in ZIF-8 (Cu-in-ZIF-8) was further modified onto screen-printed electrodes for nonenzymatic sensing of glucose in alkaline medium. The porous structure of ZIF-8 are beneficial for the unimpeded diffusion of glucose and reaction product. And as a matrix for encapsulating Cu NPs, ZIF-8 also protect the Cu NPs from dissolution and agglomeration during the electrocatalytic process. For comparison, the electrochemical performance of Cu NPs loaded on ZIF-8 (Cu-on-ZIF-8) was also investigated and it is found that Cu-in-ZIF-8 exhibited higher activity and better stability for cyclic test toward the oxidation of glucose in alkaline media. Additionally, Cu-in-ZIF-8 based glucose sensor also shows a favorable sensitivity and selectivity. [ABSTRACT FROM AUTHOR]

The Inside Back Cover picture shows that the cathodization treatment on Cu–MOF results in the evolution of a structure with improved electrocatalytic activity for glucose oxidation. More information can be found in the Communication by H. Zhao, M. Lan and co‐workers on page 246 in Issue 2, 2017 (DOI: 10.1002/celc.201600625). [ABSTRACT FROM AUTHOR]