MAX phase-derived woolen ball-like K2Ti8O17 with excellent surface-enhanced Raman scattering property

Abstract

In surface-enhanced Raman scattering (SERS) applications, the MAX phase is typically acid etched to address deficiencies, while the more accessible alkali corrosion products are neglected. The woolen ball-like K2Ti8O17 (KTO) nanomaterial is synthesized via an efficient hydrothermal surface corrosion reaction between KOH solution and MAX phase Ti2AlN, which exhibits excellent SERS capabilities to the contaminating dyes. The enhancement factors are 2.33 × 105, 1.04 × 105 and 2.22 × 105 with lowest limits of detection of 10−7 M, 10−6 M and 10−7 M for crystal violet, rhodamine 6G and methylene blue, respectively, indicating that KTO is a highly desired candidate of SERS substrate material. Meanwhile, KTO shows excellent SERS performance for chrysoidine in simulated seawater, which proves its practical application value. The excellent SERS performance of KTO is attributed to the charge transfer mechanism, which is made possible by the appropriate energy band structure and the robust adsorption capacity. In conclusion, a novel method for the synthesis of KTO is investigated and its reaction process and enhancement mechanism are exhaustively characterized and described. The woolen ball-like KTO exhibits remarkable SERS properties and potential applications.