Noble‐Metal Free Indium Oxide Nanofibers Heterojunctions Facilely Constructed for Markedly Enhanced Performance in Both SERS Detection and Photocatalysis

The construction of the cost-effective materials that are convenient to be used for sustainable detection and efficient removal of toxic pollutants is highlighted in practical application. Herein, a plug-and-play bifunctional fiber-like In₂O₃ heterojunction (ETI) is constructed by growing indium metal-organic frameworks directly onto an etched titanium sheet (ET) and subsequently annealed. The results show that the noble-metal free In₂O₃ nanofibers induced by ET can sensitively response to trace triphenylmethane pollutant-bright green (BG, as low as 1 × 10^-11 m, analysis enhanced factor (AEF) = 7.68 × 10⁵). In addition, excellent selectivity and repeatability for surface-enhanced Raman scattering (SERS) detection of BG can be achieved on the uniform ETI substrate. Moreover, the portable ETI substrate shows significant photocatalytic efficiency and maintains stability throughout cycles in degrading BG, which is greatly superior to some comparisons. The highly efficient SERS and photocatalytic activity of ETI can be mainly attributed to the confinement effect in the nanofibers and the strong internal electric field generated at multiple heterogeneous interfaces between TiO₂ nanoparticles "islands" and In₂O₃ nanofibers on the ET. This study will establish a new foundation for developing noble-metal-free substrates flexibly used in detecting and eliminating organic pollutants in wastewater.