Chi 660e electrochemical analyzer

The Mott-Schottky plots and electrochemical impedance spectroscopy (EIS) were obtained on a CHI-660E electrochemical analyzer (CH Instruments, Shanghai, China) in a standard three electrode configuration. The Ag/AgCl and Pt sheet were used as the reference electrode and the counter electrode, respectively. The working electrode was prepared on indium doped tin oxide (ITO) substrates. The 1 mg sample was dispersed in a mixture containing 0.98 mL of anhydrous ethanol and 0.02 mL of Nafion solution by ultrasonication for 30 min. The obtained slurry was dropped onto the surface of the ITO glass with a size of 1 × 1 cm², and then dried at room temperature. 0.5 M Na₂SO₄ was employed as the electrolyte. The Mott-Schottky plot was obtained through measurement of the capacitance as a function of potentials at 1 kHz. The EIS measurements were carried out in the frequency range of 10⁻² to 10⁵ Hz with a 10 mV amplitude.

Tyrosinase (TYR, EC1.14.18.1) from mushroom, l-3,4-dihydroxyphenylalanine (l-DOPA), kojic acid (KA), catechin, ECG, and EGCG were purchased from Sigma-Aldrich. Nitric acid and dimethyl formamide (DMF) were purchased from Beijing Chemical Works. Multiwalled carbon nanotubes (MWCNTs) were purchased from the Nanotech Port Co. Ltd (Shenzhen, China). Before use, the MWCNTs were acidified by Nitric acid.^{23 (link)}Spectrophotometer reader (BioTek Instruments Inc., USA) and High Performance Liquid Chromatograph (HPLC: Shimadzu Instruments Inc., Japan) were used to measure the inhibitory activity of the Tyrosinase inhibitors. CV experiments were performed in a standard three-electrode electrochemical cell with a CHI 660E electrochemical analyzer (CH Instruments, Chenhua Co., Shanghai, China). Oxygen consumptions of Tyrosinase interacting with TPs were monitored with YSI 5000 dissolved oxygen meter (YSI Inc., American).

Electrochemical tests were evaluated by assembling CR2032 coin type half-cells in an argon-filled glove box (O₂ < 0.1 ppm, H₂O < 0.1 ppm). The working electrodes were fabricated by mixing 70 wt% of as-prepared active materials, 20 wt% acetylene black and 10 wt% polyvinylidene fluoride (PVDF) binder using N-methyl pyrrolidone as solvent and the mass loading of an electrode of 0.62 mg/cm². Sodium disks were cut into a round shape with 13 mm and employed as the counter electrode and glass fiber was used as the separator. The obtained homogeneous slurry was coated onto the current collector (Al foil) and dried in a vacuum oven at 60 °C overnight. In the cells, 1 M NaClO₄ in ethylene carbonate/diethyl carbonate (EC/DEC, 1:1 v/v), ethylene carbonate/dimethyl carbonate (EC/DMC, 1:1 v/v) with the addition of 5% fluoroethylene carbonate, and tetraethylene glycol dimethyl ether (TEGDME) were used as the electrolytes for SIBs. Galvanostatic discharge/charge tests were collected on a Neware multichannel battery system between 0.1 V and 2.5 V. Cyclic voltammetry (CV) profiles were carried out using a CHI660E electrochemical analyzer (CH Instruments Inc., Shanghai, China) and electrochemical impedance spectroscopy (EIS) was performed on an Autolab electrochemical workstation.

Electrochemical measurements were performed with a CHI 660E electrochemical analyzer (CH Instruments, Inc., Shanghai). All electrochemical tests adopt the traditional three-electrode system, and the experimental results were obtained under normal temperature and pressure.