Transition metal oxide (TMO)-based semiconductor nanomaterials (NMs) have been progressively explored as promising substrates for surface-enhanced Raman scattering (SERS). The design and synthesis of highly stable, extremely sensitive, exceptionally selective SERS substrates, solely based on defects engineered in TMO-based NMs, have gained significant interest. This work demonstrates a simple hydrothermal route to synthesize substoichiometric V2O5-x flexible nanobelts without the use of surfactants, stabilizing agents, reducing agents, or structure-directing agents. Furthermore, the V2O5-x nanobelts proved to be highly effective as a SERS substrate for the sensitive detection of methylene blue (MB), achieving a remarkable maximum enhancement factor of up to 6.75 × 109 and a detection limit as low as the picomolar level. This performance is the best among metal oxide semiconductors and is comparable to that of noble metals, even without the presence of a “hot spot.” Additionally, the V2O5-x nanobelts demonstrate excellent selectivity as a “SERS Tweezer,” enabling the precise detection of MB even in the presence of interfering analytes across binary, ternary, and quinary mixtures. Notably, V2O5-x nanobelts successfully detected melamine and ethephon for the first time using a TMO-based SERS substrate. In addition, the detection limit for SERS using a V2O5-x substrate reached 3 ppm of melamine in liquid milk. Thus, our results clearly demonstrate that metal oxide semiconductors can be transformed into cost-effective, SERS-active substrates through defect engineering. These engineered substrates exhibit high sensitivity, selectivity, stability, recyclability, and biocompatibility?comparable to or even surpassing those of noble metal nanomaterial-based SERS substrates. This advancement could enable their effective use in detecting contaminants in foods and food ingredients.

https://doi.org/10.1016/j.eurpolymj.2026.114762

This manuscript presents a novel electrocatalyst for direct ammonia fuel cells that integrates atomic-scale bimetallic-skin engineering with a 3D nanoporous carbon support to optimize active site accessibility and mass transport. The study demonstrates significant scientific merit by utilizing lattice strain and electronic tuning to mitigate catalyst poisoning and shift the reaction pathways, providing a comprehensive strategy for advancing high-performance electrocatalysts in sustainable energy applications.

Equal Contribution from the first two authors

Equal Contribution from the first two authors

https://doi.org/10.1002/slct.202507548