Sta 449c instrument

To verify the results obtained from the Raman analysis, the well-established TG analysis was employed to assess the CaCO₃ quantity. A NETZSCH STA 449C instrument (NETZSCH, Selb, Germany), which worked under an inert environment (N₂) with a flow rate of 1 mL/min, was used. The samples were placed in an alumina (Al₂O₃) crucible and heated from room temperature to 1000 °C at a heating rate of 20 °C/min. The derivative thermogravimetric curves (DTG) were also recorded simultaneously. The CaCO₃ quantity was calculated by following its decomposition to CaO and CO₂ at a temperature of around 470 °C~820 °C.

Fourier transform infrared spectroscopy (FTIR) measurements were performed on a Nicolet 6700 spectrometer equipped with an MCT detector. Thermogravimetric analysis (TGA) was undertaken with a NETZSCH STA 449C instrument, and measurements were performed from 25 °C to 700 °C, at a heating rate of 20 °C/min in N₂. Differential scanning calorimetry (DSC) was performed on a NETZSCH DSC 200 PC unit from –50 °C to 300 °C, at a heating rate of 10 °C/min in N₂. Raman spectra were obtained with a laser confocal microscope spectrometer (American Thermoelectric Corporation). The surface morphologies of the XMPC were visualized by SEM (SSX-550, Shimadzu, Kyoto, Japan). An X-ray diffraction (XRD) study of the samples was carried out on a Bruker D8 Focus +X-ray diffractometer operating at 30 kV and 20 mA with a copper target (l = 1.54 Å) and at a scanning rate of 1° min⁻¹. The surface areas were determined by Brunauer–Emmett–Teller (BET) analysis (AUTOSORBiQ2, Quantachrome, Boynton Beach, FL, USA). Metal ion concentrations were determined by atomic absorption spectroscopy (SSX-550, Shimadzu, Kyoto, Japan).

Thermogravimetric analysis (TGA) was performed on initial pre-extracted lignite, HDPE, and their mixture in the mass ratio of 1:1 using a Netzsch STA 449C instrument (Netzsch-Gerätebau GmbH, Selb, Germany). Samples were heated from 27 °C to 900 °C at a heating rate of 10 °C/min. The heating rate of 10 °C/min was chosen because, at high heating rates, especially for endothermic reactions, the furnace temperature increases faster than the sample temperature, resulting in error of measurement, particularly when analysis is carried-out in non-isothermal mode [46 (link)]. Nitrogen was used as the purge gas with the flow rate of 60 cm³/min. The flow rate of nitrogen was chosen to optimize the analysis of gases. Fourier transform infrared spectroscopy (FTIR) was applied for qualitative identification of generated gases, using ATI MATSON Infinity Series FTIR instrument (Labx, Midland, ON, Canada). TGA-FTIR analysis was done at the Montanuniversität Leoben, Department of Product Engineering.

The as-prepared LCNT was further treated in 5 % H₂/Ar for 4 h at 400 ^oC, 600 ^oC and 800 ^oC in a tube furnace to obtain the reduced perovskite samples. The preparation of Pt-LCNT reduced samples was carried out by treating the samples at three different temperatures, denoted as LCNT_0.5Pt800R, LCNT_Pt600R and LCNT_Pt400R, respectively.
TGA measurements were performed on a NETZSCH STA 449 C instrument using Proteus thermal analysis software. The initial weight of the sample is about 40 mg. The mass was recorded when heated to 800 ^oC under flowing 5% H₂/Ar (30 ml·min⁻¹), with a heating rate of 5 °C·min⁻¹. Thereafter, an isothermal procedure was carried out for 10 h at 800 ^oC. The blank with an empty crucible was recorded under the same conditions and subtracted from the sample data. The raw data were numerically differentiated to obtain differential thermogravimetry curves.
TPR was carried out using a Micromeritics AutoChem II 2920 instrument with about 100 mg samples. The sample was loaded in the quartz glass reactor and purged with He at 50 ml·min⁻¹ flow rate, at 400 °C for 1 h and cooling down to 50 °C to remove any trace of adsorbates. Then, TPR was conducted in 10 % H₂/Ar at a flow rate of 50 ml·min⁻¹. The temperature raised from room temperature to 1000 °C with a heating rate as 10 °C·min⁻¹.

The scanning electron microscopy (SEM) images were obtained by JEOL JSM-7800F with an energy dispersive spectrometer (EDS). The transmission electron microscopy (TEM) images and selected area electron diffraction (SAED) patterns were recorded by JEOL JEM-F200. The aberration-corrected high angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) images were collected by JEOL JEM-ARM200F. The X-ray photoelectron spectroscopy (XPS) analysis was performed on Kratos Axis Ultra DLD spectrometer. Raman spectra were recorded with Horiba LabRam HR Evolution spectrometer. Nitrogen adsorption-desorption isotherm measurement was conducted using Micromeritics ASAP 2460 system. The thermogravimetric analysis (TGA) was investigated by using NETZSCH STA 449 C instrument. The ultraviolet-visible (UV-vis) spectra were performed by Shimadzu UV-2700 spectrophotometer. The in-situ X-ray diffraction (XRD) patterns were performed using Bruker D8 Advance with Cu Kα radiation (λ = 0.15406 nm) at 40 kV and 40 mA. The X-ray absorption structure (XAS) spectra (W L-edge) were measured in Shanghai Synchrotron Radiation Facility (SSRF).

FTIR spectra were recorded on a Perkin-Elmer GX spectrometer (Perkin-Elmer, USA) on KBr discs. ¹H NMR and ¹³C NMR spectra were obtained with an Avance-500 NMR spectrometer (Bruker, Switzerland) in deuterated chloroform (CDCl₃) by using tetramethylsilane as an internal standard. Elemental analysis was carried out on a Vario EL III elemental analysis instrument (Elementary, Germany) through ICP–atomic emission spectroscopy. TG/DSC analysis was performed on an STA449C instrument (Netzsch, Germany) under an argon atmosphere at a heating rate of 10°C min⁻¹.