Microperoxidase-11@PCN-333 (Al)/three-dimensional macroporous carbon electrode for sensing hydrogen peroxide

In this work, a novel hydrogen peroxide (H 2 O 2 ) biosensor was developed based on the microperoxidase-11 (MP-11) encapsulated in metal-organic frameworks, PCN-333 (Al) (PCN stands for porous coordination network), which was grown on the three-dimensional (3D) kenaf stem-derived porous carbon (3D-KSC) firmly and uniformly. The ball-flower-like PCN-333 (Al) with mesopores of 5.5   nm was especially suitable for encapsulating MP-11 (1.1   ×   1.7   ×   3.3   nm). Scanning electron microscopy and energy dispersive X-ray spectroscopy were used to characterize the 3D-KSC electrode and the 3D-KSC/PCN-333 (Al)@MP-11 electrode. UV–vis spectroscopy was used for characterizing the encapsulation of MP-11 in the 3D-KSC/PCN-333 (Al) electrode. Cyclic voltammetry and differential pulse voltammetry were used to characterize the electrochemical behaviors and performance of the biosensor. The results showed that the encapsulated MP-11 molecules showed a better performance than free enzyme. Under the optimized experimental conditions, the resulted H 2 O 2 biosensor exhibited a wide linear range from 0.387   μM to 1.725   mM and a low detection limit of 0.127   μM with good stability and high selectivity, which was superior to some H 2 O 2 biosensors.