Browsing by Author "Zhang, Zixin"

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    Flexible, scalable hierarchical graphene foam decorated with nickel layer for highly sensitive enzyme-free glucose sensing
    (Elsevier, 2024-11-05) Ji, Xiaodong; Jin, Huihui; Qian, Wei; Wang, Zhe; Zhang, Zixin; Yang, Zhugen; He, Daping
    Developing functional electrode materials for enzyme-free glucose electrochemical sensing is indispensable and challenging for rapid detection and instant diagnosis. Optimizing the microstructure of electrodes to enhance molecule accessibility, facilitate rapid mass transfer, and enlarge electrochemical active surface area is critical prerequisite for improving the electrochemical analytical performance. Herein, we develop a flexible graphene foam electrode with high conductivity and multilayer channel structure achieving efficient enzyme-free glucose sensor through one-step electrodeposition of nickel. The almost defect-free graphitic structure and layered multi-channel configuration enable the graphene foam to exhibit high conductivity, large specific surface area, and excellent mechanical performance. These properties result in efficient electron transmission and mass transfer, enabling the graphene foam to function as an excellent electrode substrate material in electrochemical sensors. Thus, the detecting electrode (Ni/GF) produced by electrodepositing nickel on graphene foam, demonstrates elevated sensitivity (1719.4 μA mM−1 cm−2), low limit of detection (0.2 μM), exceptional stability, and excellent flexibility for glucose detection. More importantly, the prepared electrode has been successfully applied to artificial sweat and tea, indicating its practical utility. The attractive analytical outcomes suggest that our layered multi-channel graphene foam has the potential to serve as a crucial foundational working electrode for designing efficient electrochemical sensor.
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    Scalable fabrication of graphene-assembled multifunctional electrode with efficient electrochemical detection of dopamine and glucose
    (Springer, 2023-02-22) Ji, Xiaodong; Zhao, Xin; Zhang, Zixin; Si, Yunfa; Qian, Wei; Fu, Huaqiang; Chen, Zibo; Wang, Zhe; Jin, Zhugen; He, Daping
    Conventional glassy carbon electrodes (GCE) cannot meet the requirements of future electrodes for wider use due to low conductivity, high cost, non-portability, and lack of flexibility. Therefore, cost-effective and wearable electrode enabling rapid and versatile molecule detection is becoming important, especially with the ever-increasing demand for health monitoring and point-of-care diagnosis. Graphene is considered as an ideal electrode due to its excellent physicochemical properties. Here, we prepare graphene film with ultra-high conductivity and customize the 3-electrode system via a facile and highly controllable laser engraving approach. Benefiting from the ultra-high conductivity (5.65 × 105 Sm−1), the 3-electrode system can be used as multifunctional electrode for direct detection of dopamine (DA) and enzyme-based detection of glucose without further metal deposition. The dynamic ranges from 1–200 µM to 0.5–8.0 mM were observed for DA and glucose, respectively, with a limit of detection (LOD) of 0.6 µM and 0.41 mM. Overall, the excellent target detection capability caused by the ultra-high conductivity and ease modification of graphene films, together with their superb mechanical properties and ease of mass-produced, provides clear potential not only for replacing GCE for various electrochemical studies but also for the development of portable and highperformance electrochemical wearable medical devices.
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    Well-structured 3D channels within GO-based membranes enable ultrafast wastewater treatment
    (Springer, 2022-09-03) Fu, Huaqiang; Wang, Zhe; Li, Peng; Qian, Wei; Zhang, Zixin; Zhao, Xin; Feng, Hao; Yang, Zhugen; Kou, Zongkui; He, Daping
    Graphene oxide (GO)-based membranes have been widely studied for realizing efficient wastewater treatment, due to their easily functionalizeable surfaces and tunable interlayer structures. However, the irregular structure of water channels within GO-based membrane has largely confined water permeance and prevented the simultaneously improvement of purification performance. Herein, we purposely construct the well-structured three-dimensional (3D) water channels featuring regular and negatively-charged properties in the GO/SiO2 composite membrane via in situ close-packing assembly of SiO2 nanoparticles onto GO nanosheets. Such regular 3D channels can improve the water permeance to a record-high value of 33,431.5 ± 559.9 L·m−2·h−1 (LMH) bar−1, which is several-fold higher than those of current state-of-the-art GO-based membranes. We further demonstrate that benefiting from negative charges on both GO and SiO2, these negatively-charged 3D channels enable the charge selectivity well toward dye in wastewater where the rejection for positive-charged and negative-charged dye molecules is 99.6% vs. 7.2%, respectively. The 3D channels can also accelerate oil/water (O/W) separation process, in which the O/W permeance and oil rejection can reach 19,589.2 ± 1,189.7 LMH bar−1 and 98.2%, respectively. The present work unveils the positive role of well-structured 3D channels on synchronizing the remarkable improvement of both water permeance and purification performance for highly efficient wastewater treatment.