A CeO2@MnO2 core–shell hollow heterojunction as glucose oxidase-like photoenzyme for photoelectrochemical sensing of glucose

Nanomaterial-based photoenzyme with bifunction is considered as promising mimetic enzyme in mimicking physiological processes. However, the synthesized design of the enzyme is still a significant challenge. Herein,CeO2@MnO2 core–shell hollow nanosphere was firstly fabricated by in situ growth of MnO2 nanolayer on the hollow CeO2 nanosphere. The prepared heterojunction exhibited excellent photoelectrochemical (PEC) performance because their two-phase interface could facilitate electron transfer under illumination. Meanwhile, the heterojunction had glucose oxidase (GOx)-like photoenzyme property and could catalyze the oxidation of glucose in O2-saturated PBS (pH 7.0) buffer solution at the bias potential of 0.50 V under visible-light irradiation. The result resulted in the decrease of the photocurrent of CeO2@MnO2 heterojunction/FTO electrode. Therefore, a novel non-enzymatic PEC sensor was constructed to detect glucose based on the PEC performance and GOx-like photoenzyme property of CeO2@MnO2 heterojunction under visible-light irradiation. Under the optimized conditions, the detection limit was down to 0.07 μM. Meanwhile, the proposed PEC sensor possessed acceptable selectivity, reproducibility and stability. Moreover, the non-enzymatic biosensor was successfully applied to detect glucose levels in human serum samples.