ZrO₂-embedded nitrogen-doped carbon-derived MOF/COF for supercapacitors

Porous materials, including hybrid materials (e.g., metal-organic frameworks, MOFs) and pure organic materials (e.g., covalent organic frameworks, COFs), were investigated for electrochemical energy storage. This study produced a hybrid material composed of UiO-66 MOF and a COF, which was subsequently carbonized at different temperatures to yield ZrO₂-embedded nitrogen-doped carbon for supercapacitor applications. The materials were analyzed using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results confirmed the synthesis of UiO-66@COF and the generation of ZrO₂@N-doped carbon through post-carbonization. Electrochemical experiments revealed that the carbonized composite exhibits enhanced capacitance performance compared with UiO-66 and COF materials. The UiO-66@COF_700 electrode showed a specific capacitance of 195 F/g at 1 A/g, remarkable rate capability, and stable cycling performance over 5000 cycles. The energy storage mechanism includes both capacitive and diffusion components, with a primary emphasis on surface contributions following carbonization. The results demonstrate that carbon composites produced from MOF-COF are effective electrode materials for supercapacitors.