Electronic Supporting Material on the Microchimica Acta publication
3D nitrogen-doped graphite foam@Prussian blue: an electrochemical sensing platform for highly sensitive determination of H2O2 and glucose
Yu Zhang 1, Bintong Huang 1,Feng Yu 3, Qunhui Yuan 4, Meng Gu5, Junyi Ji 6, Yang Zhang 2,7, *, Yingchun Li 2, *
1Key Laboratory of Xinjiang Plant Resources and Utilization, Ministry of Education, School of Pharmacy, Shihezi University, Shihezi, 832000 China
2 College of Science, Harbin Institute of Technology, Shenzhen, 518055, China.
3 Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan, School of Chemistry and Chemical Engineering, Shihezi University, Shihezi, 832003, China
4School of Materials Science and Engineering, Harbin Institute of Technology, Shenzhen, 518055, China
5Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
6Collage of Chemical Engineering, Sichuan University, Chengdu, 610000, China
7Harbin Institute of Technology (Shenzhen), Shenzhen Key Laboratory of Organic Pollution Prevention and Control, Shenzhen, Guangdong, 518055, China
* Corresponding authors
Yingchun Li
E-mail address:
Tel/Fax: +86-755-86239466
Yang Zhang,
E-mail address:
** Correspondence to: Y. Li, College of Science, Harbin Institute of Technology, Shenzhen, 518055, China.
- Preparation of GF
Graphite foam (GF) was prepared by chemical vapor deposition (CVD) method similar to the previous report[1]. Briefly, nickel foam, used as the template, was exposed to CH4 at 1050 °C for 1 h. Afterwards, the system was slowly cooled to room temperature, during which most of the carbon atoms precipitated at nickel surface, eventually forming a continuous graphite coating with a wall thickness of tens of nanometers. Then the nickel foam was completely removed by submerging the material in solution consisting of 1 M FeCl3 and 2 M HCl for 5 h [2]. The GF was carefully washed by distilled water and dried for subsequent use.
- Effect of working gas and doping time on N-GF fabrication
The plasma power supply used in the experiment is of high frequency and high voltage, which can provide sinusoidal AC voltage of 0~30 kV and 9~16 kHz. DBD plasma treatment was performed in a system including a quartz disk as vacuum chamber, a mechanical vacuum pump, a 13.56 MHz RF power supply and a gas flow-rate control system.Two kinds of working gases, i.e. pure N2and mixture of NH3 (0.125 vol.%) and N2, were employed as nitrogen source. RF power was set to be 120 W. Dried GF was placed at the center of a quartz disk. Before discharge, working gas passed through gas tubes for 15 min at the rate of 40 mL/min to expulse the air in reaction chamber.
Table S1 summarizes atomic fraction of C, N, and O in different samples obtained from XPS analysis. Before doping process, no nitrogen atom was found (GF). When N2 was used and the discharge time was 5 min, N atom was still not detected (N-GF1). Increasing the time to 10 min resulted in nitrogen percentage of 0.36% in GF (N-GF2). In comparison, mixture of NH3 and N2 as the source led to improved nitrogen doping, where the sample N-GF3and N-GF4showed N percentage of 1.32% and 1.49%, with treatment time of 5 min and 10 min, respectively. Higher doping efficiency of NH3-N2 mixture may be ascribed to the fact that under plasma condition, NH3 molecules can be easily ionized into highly reactive N and H free radicals, and the ionized N can dope into graphene. As for N2molecules, they has more difficulty to be ionized under the same condition [3]. Longer treatment time naturally produces more reactive N free radicals and hydrogen free radicals for more N doping in GF [4].
The above results indicated the successful doping whenNH3-N2 was employed as the working gas. Therefore, considering the practical energy consumption and doping efficiency,we choseNH3-N2 and treatment time of 10 min for succeeding experiments.
Table S1 Atomic concentration of C, N, and O of GF grown via CVD method and N-GF under different N doping conditionsa.
Sample / Working gas / Doping time (min) / C 1s(%) / N 1s (%) / O 1s (%)GF / - / - / 97.96 / - / 2.04
N-GF1 / N2 / 5 / 94.32 / - / 5.68
N-GF2 / N2 / 10 / 93.01 / 0.36 / 6.63
N-GF3 / NH3-N2 / 5 / 85.87 / 1.32 / 12.81
N-GF4 / NH3-N2 / 10 / 80.67 / 1.49 / 17.84
aN doping was achieved by individually utilizing two working gases (N2 or N2/NH3) at different discharge times. Each sample was tested two different parts and shown with the average percentage value of each element.
Fig. S1is EDS spectra of NGF and PB/NGF. In Fig. S1A, peaks of C, N and O are observed, displaying that NGF is successfully prepared. After PB deposition, Fe, Cl and K are found (Fig. S1B), which confirms the presence of PB particles.
Fig. S1.EDS spectra of NGF(A) and PB/NGF(B).
Fig.S2 displays general overview for an oxidase and PB modified electrode, in which GOx catalyzes oxidation of glucose and the produced H2O2 is then reduced by PW.
Fig. S2. Working principle of the proposed biosensor based on PB and GOx towards glucose sensing.
References
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2. Zhai X, Ding Y (2017) Nanoporous Metal Electrocatalysts for Oxygen Reduction Reactions. Acta Phys-Chim Sin
3. Zhou Q, Zhao Z, Chen Y, Hu H, Qiu J (2012) Low temperature plasma-mediated synthesis of graphene nanosheets for supercapacitor electrodes. JMaterChem 22 (13):6061-6066
4. Flynn, Cormac (2013) Atmospheric Pressure Plasma Modification of Biomaterials in Air and NH3/N2 gas mixtures. University of Ulster