Co(OH)2/TiO2 heterojunction for selective SERS detection of anionic dyes

Co(OH) 2 modified TiO 2 (Co(OH) 2 /TiO 2 ) was fabricated by a simple precipitation method and applied as a surface enhanced Raman scattering (SERS) substrate. Using triphenylmethane dye acid blue 83 as the analyte, the SERS substrate showed high sensitivity with a detection limit of 1 × 10 –7  M and high signal reproducibility with a relative standard deviation of 8.9%. Moreover, the substrate can also be used to in situ monitor the catalytic degradation of Acid blue 83. In addition, compared with cationic triphenylmethane dye, the Co(OH) 2 /TiO 2 substrate presented stronger SERS activity towards anionic counterparts. The easy preparation and high sensitivity and selectivity towards anionic dyes of Co(OH) 2 /TiO 2 provides a robust alternative for promoting the practical application of semiconductor-based SERS substrate in selective detection.