Preparation of layered carbon nitride/titanium-based metal skeleton materials and study on their electrorheological properties

<i>Background</i>: as an intelligent material, electrorheological fluids (ERFs) comprise a suspension system consisting of dielectric particles and/or their composites dispersed in an insulating liquid. In this article, MOF/g-C₃N₄ composite nanoparticles were successfully synthesized and demonstrated an excellent ER effect. <i>Methods</i>: first, the precursor for g-C₃N₄ was synthesized using a high-temperature calcination method, followed by the <i>in situ</i> synthesis of MIL-125 (MOF-Ti) on the surface of layered graphitic carbon nitride using a solvothermal approach. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses were used to reveal the presence of numerous MOF particles deposited onto the surfaces of layered g-C₃N₄ nanosheets. X-ray powder diffraction confirmed the growth of MOF particles on the g-C₃N₄ precursor. The chemical composition and states were characterized through Fourier-transform infrared (FT-IR) spectroscopy and X-ray photoelectron (XPS) analyses. Additionally, BET analysis indicated the presence of abundant pore structures in the MOF/g-C₃N₄ composite nanoparticles. <i>Results</i>: lastly, rheological and dielectric properties were investigated. The ER behavior demonstrated their excellent performance, with a 10 wt% mass fraction suspension of the MOF/g-C₃N₄-0.4 based composite material and dimethyl silicone oil exhibiting a yield stress of 300 Pa at 2 kV mm^-1.