ZIF-8/Cu@Co-MOFs/TiO₂ Electrode Materials Based on Nickel Foam for High-Sensitivity Nonenzymatic Vitamin B2 Sensors and High-Performance Supercapacitors

Highly efficient electrode materials are essential in the advancement of electrochemical sensors and supercapacitors. Photoelectrochemical sensors provide exceptional sensitivity and selectivity for a broad measurement range and the simple design and cost effectiveness bode well for online analyses. Herein, the Cu@Co-MOFs and titanium dioxide (TiO2) composite are synthesized by a straightforward hydrothermal technique. ZIF-8 provides sufficient active sites for the growth of Cu@Co-MOFs and TiO2, while Cu@Co-MOF combines the advantages of Cu and Co to have more complex catalytic active sites and higher catalytic efficiency. The added TiO2 utilizes its photocatalytic performance to catalyze the entire reaction. The ZIF-8 and Cu@Co-MOFs materials are synthesized on the surface of a $1\times 1$ cm porous 3-D nickel foam at room temperature, and TiO2 is attached to the pores by annealing. The ZIF-8/Cu@Co-MOFs/TiO2 sensor exhibits an exceptional sensitivity of $598.48~\mu $ A $\cdot \mu $ M-1 cm-2 in the detection of vitamin B2. The ZIF-8/Cu@Co-MOFs/TiO2 electrode can also be used in supercapacitors due to the large energy density, high power density, extended lifespan, as well as rapid charging and discharging. The reliability and efficacy are highlighted. The multifunctional ZIF-8/Cu@Co-MOFs/TiO2 structure has great potential in different applications including electrochemical sensing and energy storage.