Enhanced Raman spectroscopy of molecules adsorbed on carbon-doped TiO₂ obtained from titanium carbide: a visible-light-assisted renewable substrate.
Titanium carbide (TiC) is an electrically conducting material with favorable electrochemical properties. In the present studies, carbon-doped TiO(2) (C-TiO(2)) has been synthesized from TiC particles, as well as TiC films coated on stainless steel substrate via thermal annealing under various conditions. Several C-TiO(2) substrates are synthesized by varying experimental conditions and characterized by UV-visible spectroscopy, photoluminescence, X-ray diffraction, and X-ray photoelectron spectroscopic techniques. C-TiO(2) in the dry state (in powder form as well as in film form) is subsequently used as a substrate for enhancing Raman signals corresponding to 4-mercaptobenzoic acid and 4-nitrothiophenol by utilizing chemical enhancement based on charge-transfer interactions. Carbon, a nonmetal dopant in TiO(2), improves the intensities of Raman signals, compared to undoped TiO(2). Significant dependence of Raman intensity on carbon doping is observed. Ameliorated performance obtained using C-TiO(2) is attributed to the presence of surface defects that originate due to carbon as a dopant, which, in turn, triggers charge transfer between TiO(2) and analyte. The C-TiO(2) substrates are subsequently regenerated for repetitive use by illuminating an analyte-adsorbed substrate with visible light for a period of 5 h.
Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India.
Vankayala
V
Kiran
Srinivasan
S
Sampath
D000327:Adsorption; D001565:Benzoates / Q000737:chemistry; D002244:Carbon / Q000737:chemistry*; D002384:Catalysis; D006358:Hot Temperature; D008027:Light; D036103:Nanotechnology / Q000379:methods*; D010777:Photochemistry / Q000379:methods; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013379:Substrate Specificity; D013438:Sulfhydryl Compounds / Q000737:chemistry; D013499:Surface Properties; D013696:Temperature; D014025:Titanium / Q000737:chemistry*
D001565:Benzoates; D013438:Sulfhydryl Compounds; C013594:4-mercaptobenzoate; C096521:titanium carbide; C009495:titanium dioxide; C014712:4-nitrothiophenolate; D002244:Carbon; D014025:Titanium