TY - JOUR
T1 - Comparative study of thermal and photo-induced reactions of NO on particulate and flat silver surfaces
AU - Kim, Ki Hyun
AU - Watanabe, Kazuo
AU - Menzel, Dietrich
AU - Freund, Hans Joachim
N1 - Funding Information:
We thank Walter Wachsmann for very able technical assistance. We acknowledge financial support from the Deutsche Forschungsgemeinschaft within priority program SPP1093 (Dynamik von Elektronentransferprozessen an Grenzflächen), the German–Israeli Foundation (Dynamics of Electronic Processes in a Confined Environment), the Fonds der Chemischen Industrie , and the NEDO International Joint Research Grant on Photon and Electron Controlled Surface Processes .
PY - 2012/8
Y1 - 2012/8
N2 - Adsorption states, thermal reactions, and photoreactions at photon energies 2.3-4.7 eV of NO dimers and monomers have been compared between 8-nm silver nanoparticles (Ag NPs) formed on an Al 2O 3/NiAl(110) substrate and flat Ag(111) surfaces, by thermal desorption (TPD) and by photodesorption using mass selected time-of flight measurements. On the Ag NPs, the (NO) 2 and NO species are bound more weakly and with broader variation of adsorption states, compared to Ag(111). For (NO) 2 excitation of the Mie plasmon of the Ag NPs with p-polarized 3.5-eV photons enhances the photodesorption cross section (PCS) of NO from (NO) 2 by a factor 15 compared to Ag(111); even off the plasmon resonance up to 3-fold PCS enhancement is obtained which we ascribe to hot electron confinement. However, since translational energy distributions of photodesorbed NO are roughly the same on Ag NPs and on Ag(111), common mechanisms of photoexcitation and photoreactions apply on both types of surfaces, and neither enhancement modifies the photoinduced dynamics. Stronger particle-induced influences are observed for the photoinduced NO monomer by changes in its properties, chemical environments, and formation/decay kinetics. Our results show that NPs can lead to considerable changes of efficiency and, under favorable cases, also of branching of photoinduced surface reactions.
AB - Adsorption states, thermal reactions, and photoreactions at photon energies 2.3-4.7 eV of NO dimers and monomers have been compared between 8-nm silver nanoparticles (Ag NPs) formed on an Al 2O 3/NiAl(110) substrate and flat Ag(111) surfaces, by thermal desorption (TPD) and by photodesorption using mass selected time-of flight measurements. On the Ag NPs, the (NO) 2 and NO species are bound more weakly and with broader variation of adsorption states, compared to Ag(111). For (NO) 2 excitation of the Mie plasmon of the Ag NPs with p-polarized 3.5-eV photons enhances the photodesorption cross section (PCS) of NO from (NO) 2 by a factor 15 compared to Ag(111); even off the plasmon resonance up to 3-fold PCS enhancement is obtained which we ascribe to hot electron confinement. However, since translational energy distributions of photodesorbed NO are roughly the same on Ag NPs and on Ag(111), common mechanisms of photoexcitation and photoreactions apply on both types of surfaces, and neither enhancement modifies the photoinduced dynamics. Stronger particle-induced influences are observed for the photoinduced NO monomer by changes in its properties, chemical environments, and formation/decay kinetics. Our results show that NPs can lead to considerable changes of efficiency and, under favorable cases, also of branching of photoinduced surface reactions.
KW - Confinement of excitations
KW - Nitric oxide
KW - Photon stimulated desorption
KW - Plasmon excitation
KW - Silver nanoparticles
UR - https://www.scopus.com/pages/publications/84861900625
U2 - 10.1016/j.susc.2012.02.005
DO - 10.1016/j.susc.2012.02.005
M3 - Article
AN - SCOPUS:84861900625
SN - 0039-6028
VL - 606
SP - 1142
EP - 1151
JO - Surface Science
JF - Surface Science
IS - 15-16
ER -