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In this work, glucose oxidase (GOx) cross‐linking to a single‐wall carbon nanotubes (SWCNTs)‐poly(ethylenimine) (PEI) matrix is investigated using cyclic voltammetry (CV) for its direct electrochemistry and kinetics with presence of glucose. The electrochemistry of the bound flavin cofactor, flavin adenine dinucleotide (FAD) of the GOx, is impeded by glucose and recovered at absence of glucose, whereas a non‐specific sugar (e. g. sucrose) has no such effect. The Faradaic current of the GOx in CV decreases when the concentration of glucose increases, while the calculated electron transfer (ET) rate constant (k0) of the GOx presents a monotonic increment manner up to 144 % at 70 mM glucose concentration vs. absence of glucose in a deaerated electrolyte solution. The k0 and Faradaic current changes demonstrate a strong linear relationship to logarithmic value of glucose concentration up to 20 mM. These results suggest that the entrapped GOx, when exposing to glucose, becomes deactivated in the direct electrochemistry. Further mechanistic analysis suggests the ET reaction of GOx shows a responsive correlation to the non‐ergodicity of those active GOx sites. A control experiment using pure FAD immobilized in the matrix doesn't show responses to glucose addition. [ABSTRACT FROM AUTHOR]

Abstract: The sluggish reaction kinetics of the oxygen reduction reaction (ORR) has been the limiting factor for fuel energy utilization, hence it is desirable to develop high‐performance electrocatalysts for a 4‐electron pathway ORR. A constant low‐current (50 μA) electrodeposition technique is used to realize the formation of a uniform Co3O4 film on well‐aligned electrospun carbon nanofibers (ECNFs) with a time‐dependent growth mechanism. This material also exhibits a new finding of mT magnetic field‐induced enhancement of the electron exchange number of the ORR at a glassy carbon electrode modified with the Co3O4/ECNFs catalyst. The magnetic susceptibility of the unpaired electrons in Co3O4 improves the kinetics and efficiency of electron transfer reactions in the ORR, which shows a 3.92‐electron pathway in the presence of a 1.32 mT magnetic field. This research presents a potential revolution of traditional electrocatalysis by simply applying an external magnetic field on metal oxides as a replacement for noble metals to reduce the risk of fuel‐cell degradation and maximize the energy output. [ABSTRACT FROM AUTHOR]