Light-Driven Electron-Transfer Catalysis on Earth-Abundant CuFeS2 Nanocrystals Probed by Operando SERS
Year: 2026
Type: preprint
Abstract: Plasmonic nanoparticles possess a strong optical absorption but suffer from low catalytic activity and limited sustainability. Here, we demonstrate that earth-abundant chalcopyrite CuFeS2 nanocrystals (NCs) can serve as a dual-functional platform benefitting from a strong polaritonic absorption enabling surfaceenhanced Raman scattering (SERS), and providing at the same time high activity for light-induced electrontransfer catalysis. The nanocrystals exhibit a prominent optical resonance at 500 nm, originating from interband transitions into a Fe 3d derived intermediate band that drives the dielectric function toward the Fröhlich condition. This localized resonance yields a SERS analytical enhancement factor of ~ 3×103 for 1,2-bis(4-pyridyl)ethylene (BPE), validated by Discontinuous Galerkin Time-Domain (DGTD) electrodynamic simulations and Density Functional Theory (DFT) calculations that motivates synergistic near-field and charge transfer contributions. In addition, the CuFeS2 NCs efficiently drive the selective photoconversion of p-nitrothiophenol (NTP) to 4,4′-dimercaptoazobenzene (DMAB). Crucially, wavelength-dependent SERS and kinetic measurements prove that both Raman amplification and surface reactivity follow the optical resonance profile. Power-dependent and substrate-heating controls further confirm that this reactivity is mediated by photoexcited electron transfer into adsorbate orbitals rather than photothermal heating. By integrating a polaritonic optical enhancement with long excited state lifetimes provided by the intermediate band electronic structure in a single earth-abundant material, this work establishes CuFeS2 nanocrystals as a versatile architecture for SERS diagnostics and non-thermal photochemistry.
Source: ChemRxiv
Language: English
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7204819418