X pert powder x ray diffractometer

The X’PERT POWDER X-ray diffractometer (PANalytical, Holland) was used to collect the powder X-ray diffraction (PXRD) of samples in the θ/2θ scanning mode with Cu-Kα radiation (λ = 1.540598Å). The measurements were performed at room temperature, at a scan rate of 2°/min over a 2θ range of 4° to 50°. Silicon was used as an external calibrator. The PXRD of cocrystals were simulated by Mercury 4.3.0 at λ = 1.54056 Å, at a scan rate of 2°/min over a 2θ range of 5° to 50°.

XRD was carried out using a Panalytical X’Pert powder X-ray diffractometer with Cu Kα radiation (λ = 0.15418 nm). SEM images were obtained using a Quanta 400 FEG microscope (FEI Company). TEM images were carried out on a JEOL JEM-2010 (JEOL Ltd.). XPS measurements were performed in an ESCALAB 250 spectrometer. The ratio of Pd and Co₃O₄ was tested by ICP-OES (PerkinElmer, USA). Nitrogen adsorption isotherms were measured with a Beckman Coulter sorption analysis at 77 K in liquid nitrogen. Prior to measurements, the samples were degassed at 473 K for 10 h. Brunauer-Emmett-Teller (BET) surface area was calculated using experimented points at a relative pressure of p/p₀ = 0.05–0.25. Pore size distribution (PSD) curve was calculated by the BJH (Barrett-Joyner-Halenda) method from desorption branch. Total pore volume was estimated by nitrogen amount adsorbed at a relative pressure (p/p₀) of 0.99. All electrochemical measurements were carried out in 0.1 mol L⁻¹ KOH solution using a standard three-electrode cell at 298 K by Solartron 1287. A platinum foil (3.0 cm²) was used as counter electrode, while a saturated calomel electrode with a salt bridge (SCE, 0.241 V versus SHE) was used as reference electrode.

XRD was carried out using a Panalytical X’Pert powder X-ray diffractometer with Cu Kα radiation (λ = 0.15418 nm). SEM images were obtained using a Quanta 400 FEG microscope (FEI Company). Transmission electron microscopy (TEM) images were carried out on a JEOL JEM-2010 (JEOL Ltd.). Raman spectroscopic measurements were carried out on a Raman spectrometer (Renishaw Corp., UK) using a He–Ne laser with a wavelength of 514.5 nm. XPS measurements were performed in an ESCALAB 250 spectrometer under vacuum (about 2 × 10⁻⁹ mbar). All electrochemical measurements were carried out in 0.1 mol L⁻¹ KOH solution by using the solartron 1287 electrochemical work station using a standard three-electrode cell at 298 K. Solutions were freshly prepared before each experiment. A platinum foil (3.0 cm²) was used as counter electrode. All the potentials were measured versus a saturated calomel electrode (SCE, 0.241 V versus SHE) electrode. A salt bridge was used between the cell and the reference electrode.