Tristar ii3020

The crystal structures of the synthesized samples were determined using an X-ray diffractometer (XRD, Smart Lab, Rigaku, Tokyo, Japan). XRD measurements were carried out using CuKα X-rays within a 2θ range of 5–90° at a scanning speed of 10.0°/min. X-ray photoelectron spectroscopy (XPS, JPS-9010MC, JEOL Ltd., Tokyo, Japan) was used to analyze the surface elemental composition and binding state. XPS measurements were carried out using MgKα X-rays at a voltage of 10 kV and a current of 25 mA. The specific surface area of the samples was measured using an automatic specific surface area/pore distribution measurement device (Tristar II 3020, Shimadzu, Kyoto, Japan). The samples were degassed at 100 °C for 24 h as a pretreatment. The crystallinity of the synthesized carbon was evaluated using a Raman spectrometer (NRS-5100, JEOL Ltd., Tokyo, Japan). Raman spectra were acquired using a laser with an excitation wavelength of 532.5 nm in the wavenumber range of 100–3000 cm⁻¹ with an exposure time of 10 s and an integration count of five. Morphological observation and elemental analysis of the synthesized carbon materials were performed using a transmission electron microscope (TEM, JEM-2100, JEOL, Ltd., Tokyo, Japan) equipped with an energy-dispersive X-ray spectroscope (EDS, JED-2300, JEOL, Ltd., Tokyo, Japan). The accelerating voltage was set to 200 kV.

Surface area and pore structures of carbon supports were analyzed using the nitrogen absorption-desorption method (BET Brunauer Emmett Teller; Shimadzu, TriStar-II3020). Morphology and chemical composition of the synthesized carbon materials were characterized using transmission electron microscopy (TEM; JEOL, TEM-2100/HR), X-ray diffraction (XRD; Rigaku, Ultima IV), scanning electron microscopy (SEM; JEOL, JSM-7100F), and X-ray photoelectron spectroscopy (XPS; JEOL, JPS-9010MC). Thermal stability was evaluated by thermal gravimetric analysis (TGA; Shimadzu, TA-60WS) from room temperature to 1300 °C at an elevation rate of 10 °C /min under an air atmosphere. Prior to the thermal stability test, Pt/BZ and Pt/TOAS were annealed at various temperatures (400, 500, and 600 °C) for 2 h under Ar flow.

The nitrogen absorption–desorption method (BET, Brunauer Emmett Teller; TriStar-II3020, Shimadzu, Tokyo, Japan,) was used for analyzing the surface area, pore volume and pore diameter of the synthesized metal-N/C powder. For morphology and chemical composition analysis, the samples were characterized by scanning electron microscopy (SEM; JEOL, JSM-7100F, Tokyo, Japan), X-ray diffraction (XRD; Rigaku, Ultima IV, Tokyo, Japan) and X-ray photoelectron spectroscopy (XPS; JEOL, JPS-9010MC, Tokyo, Kanto, Japan).