Asap 2020 apparatus

The pore characteristics and surface area of the mesoporous silica specimens were investigated using a N₂ sorption experiment at 77 K by using a Micrometrics ASAP 2020 apparatus (Norcross, GA, USA). The surface functional groups of the amino-modified SBA-15 samples were inspected by a Shimadzu FTIR-8300 analyzer (Nakagyo-ku, Kyoto, Japan). The mesophases and crystalline phases of the silica specimens were assembled on an X’pert pro system X-ray diffractometer (XRD, PANalytical, Malvern, UK) equipped with Cu-kα radiation. The mesoporous structure of the functionalized and unfunctionalized silica materials was inspected by a JEM-2100 (JEOL, Akishima, Tokyo, Japan) transmission electron microscope (TEM). The surface morphologies of the silica specimens were observed through an S-3400N (HITCHI, Chiyoda, Tokyo, Japan) field-emission scanning electron microscope (SEM). The thermal decomposition path of the uncalcined SBA-15 was observed through a thermogravimetric analyzer (TGA, Mettler Toledo, OH, USA, model TGA/SDTA851e). W/W₀ represented the remaining mass of the sample.

The structures and properties of GO, RGO-Zr and Zr(OC₃H₇)₄ were characterized by various methods. X-ray diffraction (XRD) patterns were obtained on a D/MAX-RBX-ray diffractometer (Rigaku, Japan) with Cu Kα radiation (λ = 0.15418 nm). Transmission electron microscope (TEM, HT-7700, Hitachi, Japan) was used to analyze the morphology along with Field Emission Scanning Electron Microscopy (FESEM, S-4800, Hitachi, Japan). X-ray photoelectron spectroscopy (XPS) measurements were obtained on an ESCALAB 250Xi (Thermo Fisher) system with Al, Kα sources and all the binding energies were referenced to the C1s peak at 284.8 eV for the surface adventitious carbon. The binding properties were analyzed by Fourier Transform Infrared Nexus spectrophotometer (FTIR, Thermo Nicolet, America). Raman spectra were collected using an INVIA spectrophotometer (Renishaw, UK). The nitrogen adsorption–desorption isotherms were obtained on a Micrometrics ASAP 2020 apparatus at −196 °C. Finally, the surface zeta potentials of the samples were measured using a Zetasizer Nano ZS (Malvern, UK).