Investigation of Sulfur Doping in Mn-Co Oxide Nanotubes onSurface-Enhanced Raman Scattering Properties

:doping engineering is an efficient strategy tomanipulate the optoelectronic properties of metal oxides forsensing, catalysis, and energy applications. Herein, we havedemonstrated the fabrication of sulfur (S)-doped Mn-Co oxidesto regulate their band and surface electronic structures, which isbeneficial to enhancing the charge transfer (CT) between the metaloxides and their adsorbed molecules. As expected, significantlyenhanced SERS signals are achieved on S-doped Mn-Co oxidenanotubes, and the minimum detection concentration can reach aslow as 10-8M. Furthermore, the change in the electronic structurecaused by S-doping provides different microelectricfields toinfluence the orientation of the interaction between the probemolecules and the substrate. Additionally, the evaluation of theoxidase-like catalytic activity of the substrate proved that, with an increase in the ratio of Co2+/Co3+content, the number of electronson the substrate increases, which promotes the CT process and further increases the degree of CT. The nonmetallic doping route insemiconducting metal oxides can provide effective and stable SERS activity; moreover, it provides a new strategy for exploring therelationship between CT in catalysis and SERS performance of semiconductors.

Automated summary

Doping engineering can manipulate the optoelectronic properties of metal oxides for various applications such as sensing, catalysis, and energy. By fabricating sulfur-doped Mn-Co oxides, the band and surface electronic structures can be regulated, leading to enhanced charge transfer and improved SERS signals. The change in the electronic structure caused by sulfur doping also influences the orientation of the interaction between molecules and the substrate.