A metallic molybdenum dioxide with high stability for surface enhanced Raman spectroscopy

Compared with noble metals, semiconductors with surface plasmon resonance effect are another type of SERS substrate materials. The main obstacles so far are that the semiconducting materials are often unstable and easy to be further oxidized or decomposed by laser irradiating or contacting with corrosive substances. Here, we report that metallic MoO 2 can be used as a SERS substrate to detect trace amounts of highly risk chemicals including bisphenol A (BPA), dichloropheno (DCP), pentachlorophenol (PCP) and so on. The minimum detectable concentration was 10 −7 M and the maximum enhancement factor is up to 3.75 × 10 6 . To the best of our knowledge, it may be the best among the metal oxides and even reaches or approaches to Au/Ag. The MoO 2 shows an unexpected high oxidation resistance, which can even withstand 300 °C in air without further oxidation. The MoO 2 material also can resist long etching of strong acid and alkali. Semiconducting materials are potential SERS substrates as alternatives to noble metals, but often suffer from poor stabilities and sensitivities. Here, the authors use molybdenum dioxide as a SERS material, showing high enhancement factors and stability to oxidation even at high temperatures.