Raman spectrometer

Fourier-transform infrared (FT-IR) spectra were recorded using a KBr carrier containing the powder sample by employing an ENSOR spectrometer. A JSM-7610Fplus scanning electron microscope (SEM) with a primary electron energy of 5 kV was employed to examine the surface morphologies of the products. TEM images were obtained by applying a FEI Tecnai G2F30 transmission electron microscope with an accelerating voltage of 200 kV. X-ray diffraction (XRD) data were collected with a Rigaku D/Max-2500 X-ray diffractometer using a Cu target radiation source. The Raman spectrum in the range of 500–2000 cm⁻¹ was determined using a Raman spectrometer (HORIBA Scientific) with laser energy of 532 nm wavelength. Ultraviolet-visible (UV-Vis) spectra were acquired at room temperature using a SHIMADZU 3100 UV-Vis-near-IR spectrophotometer. X-ray photoelectron spectra (XPS) were collected using a VG ESCALAB MKII with Al Ka excitation (1361 eV). Binding energy calibration was based on the C 1s spectrum at 284.6 eV. The degradation intermediates of MB were analyzed using liquid chromatography–mass spectrometry (LC-MS, LTQ, Thermo Fisher Scientific, Waltham, MA, USA). All mass spectra were recorded in full scan mode over the range from 50 to 1000 m/z for qualitative analysis. Inductively coupled plasma (ICP) atomic emission spectroscopy measurements were performed on an Optima 7000 DV.

Room-temperature ADF-STEM imaging was performed using a JEOL ARM200F at 200 kV located at the David Cockayne Center for Electron Microscopy (DCCEM) within the Department of Materials at the University of Oxford. Imaging conditions used a 30-µm CL aperture with a convergence semi-angle of 22.5 mrad and a beam current of 35 pA. The acquisition angles for these images were 72.8–271 mrad. Dwell time per pixels was typically 32 µs.
The morphology of the MoS_2(1−x)Se_2x domains was characterized using scanning electron microscopy (SEM, FEI Scios, 15 kV), and the thickness was measured by AFM (Bruker Dimension Icon, tapping mode). X-ray photoelectron spectroscopy (XPS, Thermo Fisher ESCALAB 250Xi) was used to characterize the chemical composition of alloys. High-resolution transmission electron microscopy (HRTEM) imaging was performed on a field emission TEM (FEI Tecnai F20, 200 kV); selected-area electron diffraction (SAED) measurements were performed on a TEM operating at 120 kV (FEI Tecnai T12). Raman and micro-PL spectra/mapping were collected with a confocal Raman spectrometer (Horiba Jobin–Yvon HR Evolution) using a 532 nm laser as the excitation source. The laser spot size was 1 mm, and the laser power on the sample surface was kept below 60 mW.

In order to verify the particle size and topography of the working electrode, SEM images were obtained using a JEOL 5600 LV, with an accelerating voltage of 12–20 kV. Electron dispersive X-ray spectroscopy (EDS) was carried out using a solid state EDAX silicon drift detector (20,000×) on a SEM 6400. A Horiba Aramis Raman spectrometer with a 532-nm laser source was used to obtain Raman spectra. The Raman spectrometer settings for all samples also included a confocal hole of 100 nm with a 1–3% transmission filter (range from 400 to 3000), at 20 s per scan and 1× ad hoc averaging.

XRD patterns of the tin sulfide based samples were collected on a PANalytical Empyrean diffractometer with Cu K_α radiation at a scan rate of 2° min⁻¹. The surface morphologies of the samples were recorded on a SEM of JEOL JSM‐7500FA. TEM was carried out on a JEOL JEM‐2100F microscope. The XPS measurements were performed on the VG Multilab 2000 (VG Inc.) photoelectron spectrometer with the monochromatic Al K_α radiation under vacuum at 2 × 10⁻⁶ Pa. Raman analysis was performed with a Raman spectrometer of HORIBA Scientific with the laser line of 633 nm and the accumulations of 50.