Su8020

The surface morphologies and elemental compositions of the catalysts were analyzed using field-emission SEM (FE-SEM; Hitachi, Tokyo, Japan, SU8020) and TEM (JEOL Ltd., Tokyo, Japan, JEM-2100F), respectively. Raman spectroscopy (WITec, Ulm, Germany, alpha300s) was performed to identify the changes in the defects in srGO; the wavelength of the incident light was 532 nm. The electrical characteristics of the catalysts were evaluated using a source measure unit (Tektronix, Beaverton, OR, USA, Keithley 2400) in a pressure cell (M&S Vacuum, Goyang-si, Korea) under a uniaxial pressure of 5 MPa at room temperature. The crystallinities of the catalysts were determined using X-ray diffraction (XRD) analysis (Rigaku, Tokyo, Japan, Ultima IV/Rigaku), which was performed using Cu-Kα (λ = 0.15406 nm) radiation in the 2θ range of 10–85° at a scan rate of 1°/min. The Pt (wt%) concentration of the catalysts was measured using thermogravimetric analysis (Mettler Toledo, Greifensee, Switzerland, TGA/DSC1), which was performed in an air flow. The samples were heated from 3 °C to 850 °C at 10 °C/min and held at 200 °C for 2 h.

The morphologies and elemental components of the samples were characterized by SEM (Hitachi SU8020) and TEM (JEOL JEM‐2100F) equipped with energy dispersive spectrometry (EDS) at an acceleration voltage of 200 kV, respectively. The XRD patterns were recorded on an X‐ray diffractometer at 40 kV and 40 mA using Cu Kα radiation (Bruker D8 Advance). XPS spectra were collected on the ESCALAB 250Xi, (Thermo Fisher Scientific Inc., USA) equipped with Ar ion etching (2 kV; 2 µA). To obtain Brunauer–Emmett–Teller (BET) specific surface areas of the materials, nitrogen adsorption–desorption isotherms were recorded by nitrogen adsorption apparatus (ASAP2020, Micromeritics). FTIR characterization was carried out on a Bruker Vertex V70 spectrometer in the diffuse reflection mode with a Spectra Tech Collector II accessory. Depth profiling and chemical analysis data of the sample were collected on a TOF‐SIMS instrument (IONTOF GmbH, Germany 2010). The data were recorded in ultrahigh vacuum at a pressure of 10⁻⁹ Torr in a negative model.

The crystal structure of as-prepared structured catalysts was characterized by X-ray diffraction (XRD) (Japan, D/max 2500) with Cu-Kα radiation (2θ = 5–90°) at 40 kV and 30 mA.
The pore size distribution, pore volume and the Brunauer–Emmett–Teller (BET) surface areas of as-prepared structured catalysts were measured by using a Micromeritics ASAP2020 at −196 °C. Before the tests, all structured catalysts were degassed at 120 °C for 2.5 h.
The surface morphology and microstructure of as-prepared structured catalysts were carried out by using scanning electron microscopy (SEM, SU-8020) and transmission electron microscope (TEM, JEOL 2100F), respectively.
The H₂ temperature programmed reduction (H₂-TPR) measurements were carried out on an Automated Catalyst Characterization System (Autochem 2920, MICROMERITICS). Prior to H₂-TPR, the structured catalyst (1 cm × 3 cm) were heated under a gas flow of 5% O₂/He (25 mL min⁻¹) from indoor temperature to 300 °C. After cooling to room temperature, the structured catalyst was reduced under a gas flow of 10% H₂/Ar (30 mL min⁻¹) with at a heating rate of 10 °C min⁻¹.
X-ray photoelectron spectroscopy (XPS) measurements were recorded by using an XLESCALAB 250Xi electron spectrometer from VG Scientific with monochromatic Al Kα (1486.6 eV) radiation, and the peak positions were calibrated by the C 1s peaks at 284.6 eV.