Ultra dld

LEED embodied in Kratos Ultra DLD was used for tracking the crystallinity of the samples. The distortion of the image, clearly seen from the imperfection of the hexagons formed in the diffraction pattern of the graphene, is caused by the form of the lens, non‐flat samples’ surface and edge effects of the signal capturing camera.

UPS spectra were obtained from an AXIS ULTRA DLD (Kratos) with He I (21.22 eV) excitation lines and a sample bias of –9 V under a vacuum of 3.0 × 10^–8 Torr. Radiation damage from the light source on the organic films was carefully examined and no damage was detected. All measurements were carried out in the dark.

XRD patterns were supplied by Bruker D8 Advance. TEM image and EDS images were captured by Tecnai G2 F20 with EDS Inca X–Max (Oxford). Scanning electron microscopy (SEM) images were given by Gemini SEM 300. In-situ XPS measurement was operated on a Kratos-Axis Ultra DLD instrument using a xenon lamp as the light source. The binding energy of C1s at 284.8 eV was used for energy calibration. VB XPS spectra and UPS of the samples were collected by Escalab Xi+ (Thermo Scientific), and UV–vis DRS was determined by the UV-2600 system (Shimadzu). The content of K and Li was obtained from ICP-OES (PE Avio 200) and the content of H was obtained from O, N, and H co-meter (LECO ONH836). AFM images and KPFM images were captured by Bruker MultiMode 8, and the probe used was a silicon probe. During the measurement, a xenon lamp was used as the light source, and the light irradiation time was 15 min. In this case, the powder sample was dispersed in an ethanol solution and then dropped onto the silicon wafer to form a uniform film for testing.
In-situ DRIFTS characterization was operated on a Nicolet iS50 FTIR spectrometer. ¹³C isotope tracing experiment was performed by mass spectrometry (Finnigan MAT 271). The O₂ generated during the CO₂ photoreduction process was detected by a gas chromatograph (GC14C, Shimadzu) with a TCD detector.

SEM (S-3400, HITACHI, Japan) was used to examine the surface morphologies of the four groups. The surface chemical composition was examined with XPS (AXIS UltraDLD, Kratos, Japan). The release kinetics of Mg were evaluated by using a previously described method17 (link). In brief, the samples (2 cm squares) were immersed in 10 mL phosphate buffer solution (PBS) for various durations at 37 °C without agitation. The resultant solutions were analysed by using ICP-AES. The surface wettability of the samples was evaluated on the basis of contact angle measurements (Automatic Contact Angle Meter Model SL200B, Solon, China). Data were collected after a 2 μL deionized water droplet was dropped onto the sample surface and stabilized at room temperature. Three samples in each group were tested for statistical analysis.