Oxygen Vacancy‐Mediated Catalysts toward Selective H₂O₂ Reduction in Cellular Environment

Abstract

Abnormal hydrogen peroxide (H 2 O 2 ) levels in the cellular environment are closely related to cell dysfunction and serious diseases. Thus, selective and sensitive H 2 O 2 detections are urgently needed for clinical diagnosis and therapy. Herein, via surface defect engineering, an oxygen-tolerant electrocatalyst based on tin oxide for selective H 2 O 2 reduction and detection with exceptional stability and activity is designed and developed. When introduced at an appropriate level (≈5.3%), surface oxygen vacancies help lower the charge transfer resistance for enhancing the H 2 O 2 reduction reaction, while maintain the weak oxygen (O 2 ) adsorption, which enables a constant H 2 O 2 reduction (sensing) response in the electrolyte at variable oxygen levels. Moreover, the tin oxide-based assay system exhibits outstanding stability over a wide pH range of 4-9, as well as selectivity in the presence of interferent endogenous and exogenous electroactive species, which is suitable for trace H 2 O 2 monitoring secreted from NB4 cells, a model cancer cell. The oxygen vacancy-mediated tin oxide achieves the highest stability as well as high selectivity compared to reported electrochemical probes for specific H 2 O 2 detection in biological environments, with the potential for biological and biomedical applications.

Surface Oxygen Vacancy-Rich Co3O4 Nanowires as an Effective Catalyst of Luminol–H2O2 Chemiluminescence for Sensitive Immunoassay

“…Oxygen vacancy can modify the electron structure of materials and strengthen molecule adsorption on the surface, thus regulating the catalytic activity of metal oxides. ,, According to the literatures, surface oxygen vacancy as a binding site can strengthen the adsorption of H 2 O 2 and then accelerate the cleavage of the O–O bond for generation of • OH. , Because the oxygen-related species can transform into each other, • OH can convert into 1 O 2 or O 2 •– . In this work, Vo-Co 3 O 4 -4 contained abundant surface oxygen vacancies (Vo % = 51.30%), and the surface oxygen vacancies served as active sites for the adsorption and activation of H 2 O 2 to generate massive hydroxyl radicals ( • OH).…”

“…Oxygen vacancy can modify the electron structure of materials and strengthen molecule adsorption on the surface, thus regulating the catalytic activity of metal oxides. 32,35,36 According to the literatures, surface oxygen vacancy as a binding site can strengthen the adsorption of H 2 O 2 37 and then accelerate the cleavage of the O−O bond for generation of • OH. 20,38 Because the oxygen-related species can transform into each other,…”

Simultaneous Activation of Peroxydisulfate and Hydrogen Peroxide by Sulfidated Nanoscale Zero-Valent Iron for Efficient MTBE Degradation: Significant Role of Oxygen Vacancy

“…The adsorption and activation of H 2 O 2 by oxygen vacancies are regarded as thermodynamically favorable processes. ,, Since surface oxygen vacancies are electron-rich sites, hydrophilic H 2 O 2 is inclined to adsorb on them, and O–O bond of H 2 O 2 is subsequently elongated and cleaved. Thus, oxygen vacancies serve as the active sites for the generation of adsorbed radicals ( · OH ads ) over the surface of activators. , It can explain the altered conversion of H 2 O 2 and improved H 2 O 2 utilization in the S-nZVI@BC/Bi-ox system.…”

Oxygen Vacancy Engineering of FeOx toward Oxygen-Tolerant Hydrogen Peroxide Reduction for Reliable Bioassays

“…As an alternative, the cathodic reduction method for H 2 O 2 detection can alleviate this drawback, but it may introduce another problem in that oxygen is reduced at the same potential as H 2 O 2 . Because the oxygen level in aqueous solution is relatively low and easily fluctuates with temperature or pressure changes, the related reduction current will not be stabilized and will affect the accuracy of the current output, which in turn limits the applicability of this method. , Therefore, it is important to develop a catalyst with high activity, selectivity, and stability to improve the accuracy of H 2 O 2 detection by using the cathodic reduction approach.…”