Superoxide-Triggered Luminol Electrochemiluminescence for Detection of Oxygen Vacancy in Oxides

Abstract

Oxygen vacancy is known to act as a reactive center in oxides to produce radicals. Currently, X-ray photoelectron spectra (XPS) become a unique spectral tool for analyzing oxygen vacancy based on the differences in atomic number ratios between metal ions and lattice oxygen. In this work, it was found that the superoxide radical (O2 •–)-luminol electrochemiluminescence (ECL) intensity linearly increases with increasing the oxygen vacancy concentrations of TiO2 samples coated on the electrodes. An experimental study of the mechanism demonstrates that an increase in oxygen vacancy concentrations could lead to an increase in the generation of O2 •–, resulting in an increase in the O2 •–-related luminol ECL signals. Accordingly, we have developed a rapid and simple O2 •–-luminol ECL platform to detect oxygen vacancy in TiO2 samples, based on the relationship between O2 •– generation and oxygen vacancy. The proposed ECL platform exhibits good reproducibility and stability through the parallel ECL measurements. Moreover, the feasibility is verified by analyzing the oxygen vacancy concentrations in different TiO2 samples with varying the Co, Cr, Fe, and N doping concentrations. The oxygen vacancy concentrations obtained by the proposed ECL method could match well with those obtained by conventional XPS measurements. Our successful construction of the ECL platform will significantly promote the development of the oxygen vacancy detection in oxides and deepen the understanding of the relationship between oxygen vacancy and radicals.

Self-Supply of H2O2 and O2 by Hydrolyzing CaO2 to Enhance the Electrochemiluminescence of Luminol Based on a Closed Bipolar Electrode

“…We can see that the superoxide anion radical (O 2 •– ) played an important role during the process of luminol ECL reaction. Nitroblue tetrazolium, as a typical O 2 •– capture agent, was added to the anodic cell containing glucose and luminol. After electrochemistry scanning for 20 cycles through CV, blue precipitates were deposited on the sides of the driving electrode.…”

“…•− capture agent, 26 was added to the anodic cell containing glucose and luminol. After electrochemistry scanning for 20 cycles through CV, blue precipitates were deposited on the sides of the driving electrode.…”

Developing a population-state decision system for intelligently reprogramming extracellular electron transfer in Shewanella oneidensis

“…Moreover, the X-ray photoelectron spectroscopy (XPS) analysis shows the strong peaks with binding energies of 577.70 and 587.65 eV ( SI Appendix , Fig. S8 ), attributed to the 2p 3/2 and 2p 1/2 orbitals of the Cr(III) shell, respectively ( 32 ). These results demonstrate the efficient reduction of Cr(VI) by the PSD-EET strain.…”

Rapid evaluation of oxygen vacancies-enhanced photogeneration of the superoxide radical in nano-TiO2 suspensions

“…27,29 The oxygen vacancy content of TiO 2 nanoparticles were calculated using the approximate formula (1), where V O represents the oxygen vacancies and s is the elemental sensitivity factor. 27,29,45 The calculation results indicate that the oxygen vacancies of TiO 2 samples decreased from 32.71% to 5.17% with the increase in the annealing temperature (Table S2 † Based on the above, to further investigate whether the CL was dependent on the oxygen vacancies, the nano-TiO 2 suspension with various heat-treated nano-TiO 2 were mixed with the luminol solution, and the CL was detected. As seen in Fig.…”

“…However, oxygen vacancies are elusive species, and are also oen highly diluted and therefore difficult to detect. 27,29 The presence of oxygen vacancies can be demonstrated by changing the spectral response (e.g., the Raman spectrum) as a function of the number of oxygen vacancies in the sample, [30][31][32][33][34] or by several complex techniques such as X-ray photoelectron spectroscopy (XPS), 27,35 electron spin resonance (ESR), 22 and high-resolution transmission electron microscopy (HRTEM). 20,26,30 Density functional theory (DFT) calculations have also been carried out to detect oxygen vacancies.…”