Chi 660d electrochemical workstation

All electrochemical experiments were performed with a conventional three-electrode system using a CHI 660D electrochemical workstation (Shanghai CH Instruments, Shanghai, China). An Ag/AgCl (sat. KCl) electrode, a platinum wire electrode (1 mm diameter) and a GCE were used as the reference electrode, the counter electrode, and the working electrode, respectively. CV and constant potential amperometry were carried out by using a deoxygenated (N₂-saturated) 0.1 M phosphate buffer (10 mL). Deoxygenated electrolyte solutions were prepared by bubbling high purity grade nitrogen gas through the solution at least 20 min prior to the electrochemical measurements. EIS measurements were performed with 0.1 M KCl solution containing 5 mM [Fe(CN)₆]^3−/4− under applied potential of 170 mV with the frequency range from 0.01 to 100,000 Hz with the amplitude of 8 mV. All measurements were done at room temperature.

Electrochemical measurements were performed with a CHI 660D electrochemical workstation (CH Instruments, Austin, TX) and a typical one-component three-electrode cell was used, including a working electrode, a saturated calomel electrode (SCE) as the reference electrode, and a glassy carbon counter electrode in the presence of 0.5 M H₂SO₄ as the electrolyte. The reference electrode was calibrated with respect to an in situ reverse hydrogen electrode (RHE), by using two platinum wire electrodes as the working and counter electrodes, which yields the relation E (V vs. RHE) = E (V vs. SCE) + 0.245 V. A glassy carbon electrode decorated with catalyst samples was used as the working electrode. In a typical procedure for the fabrication of the working electrode, 4 mg of CoP catalyst and 20 μL of 5% Nafion solution were dispersed in 1 mL of de-ionized water by sonication to generate a homogeneous ink. Then 5 μL of the dispersion (containing 20 μg catalyst) was transferred onto a glassy carbon electrode with a diameter of 3 mm (loading amount: 0.28 mg cm^–2). The as-prepared catalyst film was dried at room temperature. Polarization data were collected at a sweep rate of 2 mV s^–1. Electrochemical impedance spectroscopy (EIS) measurements were carried out in the same configuration at η = 56 mV or j = 10 mA cm^–2 from 100 kHz to 0.1 Hz.

UV absorption spectrum of displayed phage solution was performed on UV-1800 spectrophotometer (Shimadzu, Kyoto, Japan). Electrochemical measurements including EIS and CV were performed on a CHI 660D electrochemical workstation (CH Instruments, Chenhua, Shanghai, China) with a conventional three-electrode system composed of a modified electrode as a working electrode, a platinum wire as an auxiliary electrode and saturated calomel electrode (SCE) as reference electrode. All electrochemical measurements were carried out in [Fe(CN)₆]^3−/4− solution. The EIS spectra were recorded at 0.2 V within the frequency range of 10⁻¹−10⁵ Hz and the amplitude of 5.0 mV. AFM measurement was conducted in air at ambient pressure and humidity on the Agilent 5400 AFM system with tapping mode at scan rate of 0.5 line/s. Data analysis was performed with the Agilent technologies Picoview software 1.8.

The electrochemical measurements were performed with a CHI 660D electrochemical workstation (CH Instruments, Inc., Austin, TX, USA). A conventional three-electrode cell was used at room temperature, including glassy carbon electrode (GCE) as working electrode, Pt wire as counter electrode, and Ag/AgCl electrode as reference electrode, respectively. Electrochemical impedance spectroscopy (EIS) was performed in 2.0 mM K₃Fe(CN)₆ with 0.1 M KCl as supporting electrolyte. The morphology of the modified electrode was examined using scanning electron microscopy (SEM) system (JEOL, JSM 5600 LV, Tokyo, Japan). Contact angle images were taken on a PHOENIX-MINI (SEO Co. Ltd., Suwon, Korea) system. Raman spectroscopy was performed using a EnSpectr R532 Raman spectrometer (Enhanced Spectrometry, Inc., Torrance, CA, USA).