Browsing by Author "Zhang, Zixin"
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Item Open Access 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, DapingConventional 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.Item Open Access 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, DapingGraphene 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.