D max 2500pc diffractometer

The morphology and structure of SrHA were characterized by transmission electron microscopy (TEM, JEM-2100 ​F, Jeol Ltd., Japan) at 200 ​kV. The average length of nanoparticles was calculated using ImageJ 1.34 software (National Institutes of Health, USA) from the TEM images. The scaffolds were sputtered with gold at 10 ​mA current for 30 ​s and the morphology was observed by scanning electron microscope (SEM, Phenom ProX, Phenom-World, Netherlands) at 10 ​kV. The average pore diameter was obtained from SEM images with ImageJ 1.34 software, where at least 50 measurements were randomly selected. The elements distribution was qualitatively analyzed with a Quantax 400 energy dispersive X-ray spectroscope (EDS, Bruker, Germany). Attenuated total reflectance–Fourier transform infrared (ATR–FTIR) spectra were performed with a PerkinElmer Spectrum Two spectrometer (Waltham, MA, USA) at a resolution of 4 ​cm⁻¹ in the range of 400–4000 ​cm⁻¹. X-ray diffraction (XRD) patterns were recorded on a D/max-2500 ​P ​C diffractometer (Rigaku Co., Japan) using Cu/Ka radiation at 2θ range of 5–70°. Three specimens were tested for each sample.

X-ray diffraction (Rigaku D/MAX 2500/PC diffractometer) was performed with Cu Kα radiation. The lattice constant a₀ and the preferred orientation factors F of (111) faces of samples were calculated by the extended Bragg equation and Lotgering method (eqn (S1) and (S2)†).^55,56 The specific calculation methods were displayed in ESI.† The microstructure morphologies of nanocomposite ribbons and powders were investigated by a scanning electron microscope (SEM, Zeiss SUPRA 55) and a transmission electron microscope (TEM, JEOL JEM-2100) with selected-area electron diffraction (SAED) patterns. Some TEM specimens were also observed using high-resolution TEM (HRTEM). A Horiba Jobin-YNON co-focal laser Raman system was used to obtain the Raman spectra, equipping a He–Ne laser with an excitation wavelength of 532 nm. Thermogravimetric analysis (TGA) was performed on a Mettler-Toledo TGA/SDTA851e Thermo Analyzer from room temperature to 800 °C at a rate of 5 °C min⁻¹.

The crystallinity of corncob was measured with X-ray diffractometer (XRD), using a D/max 2500 PC diffractometer with Cu/Ka radiation source (Rigaku Corporation, Tokyo, Japan). It was operated at a voltage of 60 kV and a current of 300 Ma with a scanning speed of 0.02°/min and the 2θ range from 5° to 40°. Crystallinity index (CrI) was calculated as following. $$\text{CrI}(\%)=\frac{I_{002}-I_{\text{am}}}{I_{002}}\times 100\%.$$ I₀₀₂ and I_am imply the intensities of the peaks at near 21.4° and 16.0°, respectively.

The chemical structure and morphological features of samples was characterized by FT-IR spectrometer (Nicolet, United States) and SEM (Sigma 300, ZEISS, Germany). The hydrophobicity and enzyme accessibility of different pretreatment substrates was estimated by Rose Bengal dye and DR 28 absorption experiment using an ultraviolet-visible spectrophotometer (Tang et al., 2021 (link)). The degree of polymerization of different samples was measured by copper ethylenediamine method (Lin et al., 2020 (link)). XRD analysis was recorded by a D/MAX 2500PC diffractometer (Rigaku Corporation, Japan). Crystallinity index (CrI) was obtained by the ratio of the crystalline peak area to the crystalline peak and the amorphous peak area (Alam et al., 2020 (link)). Specific surface area was performed on Brunauer Emmett Teller (BET) assay with nitrogen gas adsorption (Micromeritics Instru-ment Corp., Norcross, United States). X-ray spectroscopy spectra were obtained with an Escalab 250Xi spectrometer (Thermo Fisher Scientific Inc., US), with nonmonochromatic Al K alph (15 kV, 300 W, 1486.8 eV). The surface coverage of lignin and carbohydrates on the surface of the samples before and after pretreatment was calculated as follows (Wan et al., 2023 (link)): ${\mathrm{S}}_{\text{lignin}}\left(\%\right)=\frac{\mathrm{O}/{\mathrm{C}}_{\text{pretreated}}-\mathrm{O}/{\mathrm{C}}_{\text{carbohydrate}}}{\mathrm{O}/{\mathrm{C}}_{\text{lignin}}-\mathrm{O}/{\mathrm{C}}_{\text{carbohydrate}}}\times 100$
${\mathrm{S}}_{\text{carbohydrate}}=1-{\mathrm{S}}_{\text{lignin}}$
$\mathrm{O}/{\mathrm{C}}_{\text{carbohydrate}}=0.83\mathrm{O}/{\mathrm{C}}_{\text{lignin}}=0.3$

The chemical compositions (%, w/w) of the substrates were measured by the NREL standard analytical method [13 ]. Analyses of the carbohydrates of the substrates were assessed by HPLC under the same conditions as enzymatic hydrolysates. CP/MAS ¹³C-NMR spectra of the substrates were conducted using a Bruker AV-III 400 M spectrometer (Germany) [19 (link)]. XRD analysis of the substrates was recorded by a D/MAX 2500PC diffractometer (Rigaku Corporation, Japan). The crystallinity indexes (CrIs) of the substrates were determined from the ratio of the crystalline peak area to the total area of crystalline and amorphous peaks. SEM images of the substrates were performed with a Phenom XL (Phenom-World, Netherlands) instrument at 10 kV. BET surface areas of the substrates were measure by analyzing of the nitrogen adsorption using an SSA-7000 surface area analyzer (Beijing Bi’aode Electronic Technology Co., Ltd., Beijing, China) after 8 h of degassing at 120 °C and 1 h of degassing at 150 °C. The measurements (chemical compositions and BET surface areas) were conducted in triplicate, and the relative standard deviation was below 5.0%. The data represented are the averages obtained from experiments.

The chemical compositions (%, w/w) of the resulting residues collected via different MTHF/H₂O system processes were also assessed by the NREL method [28 ]. SEM images of RM and resulting residues were recorded by a JSM 6700F NT (Tokyo, Japan). FT-IR of RM and resulting residues were carried out using a FT-IR microscope (Thermo Nicolet Corporation, Madison, WI, USA) equipped. XRD of RM and resulting residues were performed via a D/MAX 2500PC diffractometer (Rigaku Corporation, Tokyo, Japan). The crystallinity indexes (CrIs) of the RM and resulting residues were measured from the ratio of the crystalline area to the total area of crystalline and amorphous peaks [19 (link)].