Lü Sihua

Screening the emission sources of volatile organic compounds (VOCs) in China by multi-effects evaluation

Volatile organic compounds (VOCs) play important roles in the atmosphere via three main pathways: photochemical ozone formation, secondary organic aerosol production, and direct toxicity to humans. Few studies have integrated these effects to prioritize control measures for VOCs sources. In this study, we developed a multi-effects evaluation methodology based on updated emission inventories and source profiles, by combining the ozone formation potential (OFP), secondary organic aerosol potential (SOAP), and VOC toxicity data. We derived species-specific emission inventories for 152 sources. The OFPs, SOAPs, and toxicity of each source were estimated, the contribution and sharing of source to each of these adverse effects were calculated. Weightings were given to the three adverse effects by expert scoring, and then the integrated effect was determined. Taking 2012 as the base year, solvent use and industrial process were found to be the most important anthropogenic sources, accounting for 24.2% and 23.1% of the integrated effect, respectively, followed by biomass burning, transportation, and fossil fuel combustion, each had a similar contribution ranging from 16.7% to 18.6%. The top five industrial sources, including plastic products, rubber products, chemical fiber products, the chemical industry, and oil refining, accounted for nearly 70.0% of industrial emissions. Beijing, Chongqing, Shanghai, Jiangsu, and Guangdong were the five provinces contributing the largest integrated effects. For the VOC species from emissions showed the largest contributions were styrene, toluene, ethylene, benzene, and m/p-xylene.Graphical abstract

Electronic structure of Sn-doped C60 film

Abstract The Sn-doped C 60 film was obtained by annealing a 100A˚thick C 60 film with 6A˚thick Sn overlayer at 200°C. Photoelectron spectra show that the ration of Sn atoms to C 60 molecules in the film is about 3:1. The valence band and C 1s core level spectra of the Sn-doped C 60 film are similar to that of C 60 film. In contrast with the expectation of the reported superconductive phase of Sn- doped C 60 , no metallic conduction band with a distinct Fermi level cutoff has been observed in the valence bands portion.

Plasmon Excitation in 2D and 3D C60 Studied by Photoemission

For near monolayer (ML) C60 condensed on Sn substrate, x-ray photoemission studies of C1s level reveal a feature centered about 22eV below the main peak. Analyses show that the feature is caused by the plasmon loss of the two dimensional C60 film. Bulk plasmon loss peak (similar 28eV blow the main peak), which has been observed on thick C60 films, was not observed on the C60 films with coverage θ < 2 ML. It indicates that the 28eV energy loss feature is due to a bulk plasmon associated with the solid C60 but not a single C60 molecule.

Surface State at bar K Point of Surface Brillouin Zone on Cu{111} Surface

Electronic structure of Cu{111} surface along - line of surface Brillouin zone (SBZ) was studied using synchrotron radiation angle-resolved photoemission. A surface state located at 3.0 eV below Fermi level, near point of SBZ was observed for the first time. It is described by localized d-electron Tamm surface state.

Electron Band Structure of C60 Single Crystal Using Synchrotron Radiation

Electron band structure of C60 single crystal has been investigated using synchrotron radiation. On the cleaved (111) surface of the C60 single crystal the angle-resolved ultraviolet photoelectron spectra were measured at normal emission with varying photon energy from 12.7 to 28.2 eV. The valence band dispersions in L-Γ-L direction were successfully observed. The dispersions are 0.14 and 0.17 eV for the highest occupied molecular orbitals (HOMO) and HOMO-1 derived band respectively.

Development of Valence Bands of C60 from Submonolayer to Two and Three Dimensionality

For submonolayer amounts of C60 condensed on Sn substrate, the peaks derived from top two occupied molecular orbitals were broadened by 0.3 eV in comparison with solid C60. For coverage θ < 1 monolayer, the broadenings are independent of the coverage. It indicates that the delocalizations of electrons in valence bands of C60 are weak and the widths do not reflect the true band dispersions.

Adsorption of Oxygen on KxC60 Studied by Photoelectron Spectroscopy

Photoemission spectra of vacuum deposited K-incorporated C60–KxC60 (x ≈ 6), before and after exposure to oxygen, show that the interaction between oxygen and potassium forms an overlayer of 40 A K-O complex with stoichiometry near to that of potassium peroxide K2O2 on the surface. In contrary to the oxidation of potassium film, no potassium oxide K2O has been observed.

Photoemission Evidence for Dilute K-doped Phase KxC60 with x<0.2

A shift about 0.3eV to higher binding energy is reported in the valence band and C 1s core level of KxC60(x<0.2). Analysis shows that the result could not be interpreted by a mixture of C60 and K3C60. A dulite K-doped phase and fermi level pinning near the lowest unoccupied molecular orbital derived band caused by K-doping are proposed.

Dissociation of CO on Oxygen Contaminated Ni{001}c(2×2)-Al Surface at Room Temperature

The dissociation of CO on oxygen contaminated Ni{001}c(2×2)-Al surface at room temperature has been observed by electron energy loss spectroscopy. The CO dissociation rate is proportional to the oxygen contamination on the surface.

CO on Cu{001}c(2 × 2)-Pd Studied by High Resolution Electron Energy Loss Spectroscopy

The adsorption of CO on Cu{001}c(2 × 2)-Pd surface has been studies by electron energy loss spectroscopy. At 240 K, CO molecules are linearly bonded on the top of Pd atoms only. At 135 K, CO adsorbed both on the top position of Pd and Cu atoms which occupied preferably on Pd top position. Another possible dissociative adsorption phase of CO, which exists at room temperature, has been discussed also.