Enhanced Photocatalytic Activity Of Diamond Thin Films Using Embedded Ag Nanoparticles

Silver nanoparticles embedded into the diamond thin-'filnis enhance the optical absorption and the photocatalytic activity toward the solvated electron-initiated reduction of N2 to NH3 in water. Here, we demonstrate the formation of diamond films with embedded Ag nanoparticles" <100 nm in diameter. Cross-sectional scanning electron microscopy (SEM), energy-dependent SEM, and,energy-. dispersive X-ray analysis demonstrate the formation of encapsulated nanoparticles. Optical absorption measurements in the visible and Ultraviolet region show that the :resulting films exhibit plasmonic resonances in the visible and near-ultraviolet region. Measurements of photocatalytic activity using suprabafid gap (.lambda < 225 nm.) and sub-band gap (lambda > 225 nm) excitation show significantly enhanced ability to convert N-2 to NH3. corporation of Ag nanoparticles induces a nearly 5-fold increase in activity using-a, sub-band gap excitation with 2 > 226 nm. Our results suggest that internal photoemission, in which electrons are excited from Ag into diamond's conduction band, is an impottant prOceSS that extends the wavelength region-beyond diamond's band gap. Other factors, including Ag-induced optical scattering and formation of graphitic impurities are also discussed.