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

Facile Estimation of Surface Oxygen Vacancies in Co3O4 Catalysts with a Colorimetric Method

“…At the same time, we also measured the Raman spectra of these Co 3 O 4 samples (Figure B). The peaks near 190, 450, 500, 600, and 660 cm –1 correspond to the F 29 , E g , F 2g , F 29 , and A 1g modes of Co 3 O 4 , respectively. , The change in A 1g is due to the surface Ov concentration . The A 1g peak of Co 3 O 4 -6 showed an obvious red shift, and it had a maximum half-width value due to the presence of more Ov .…”

“…Then, the obtained ZIF-67 was pyrolyzed under an oxygen atmosphere at 500 °C to generate Co 3 O 4 nanoparticles (Co 3 O 4 -1). Finally, the Co 3 O 4 nanoparticles were treated with NaBH 4 (a reducing agent) at room temperature (25 °C) to form Ov in Co 3 O 4 nanoparticles. , Through changing the amount of the used NaBH 4 , we obtained five Co 3 O 4 nanoparticles with different surface Ov concentrations (Co 3 O 4 -2, Co 3 O 4 -3, Co 3 O 4 -4, Co 3 O 4 -5, and Co 3 O 4 -6) . The morphology of these obtained Co 3 O 4 samples was observed through TEM.…”

“…Furthermore, XPS was conducted to analyze the surface element composition and the surface oxygen state of the Co 3 O 4 samples. The full-scan XPS results (Figure S3) indicated that these samples contained Co atom, O atom, and C atom (due to absorbing CO 2 in air , ). As shown in Figure A–F, the high-resolution XPS spectra of Co 3 O 4 nanoparticles were fitted into three bands with peaks at 529.6, 530.8, and 531.7 eV, respectively.…”