Maofa Ge

Heterogeneous Uptake of Hydrogen Peroxide on Mineral Oxides

The interaction of mineral oxides (α-Al2O3, MgO, Fe2O3, and SiO2) with hydrogen peroxide was investigated using the Knudsen cell reactor. The initial reactive uptake coefficients for the commercially available powders are measured as (1.00±0.11)×10−4 for α-Al2O3, (1.66±0.23)×10−4 for MgO, (9.70±1.95)×10−5 for Fe2O3, and (5.22±0.9)×10−5 for SiO2. These metal oxide powders exhibit some catalytic behavior toward the decomposition of hydrogen peroxide excluding SiO2. H2O2 can be destroyed on Fe2O3 surface and O2 is formed. The experimental results suggest that the heterogeneous loss on mineral surface can represent an important sink of hydrogen peroxide.

Reaction of Cationic Vanadium Oxide Clusters with Ethylene in a Flow Tube Reactor

A time of flight mass spectrometer coupled with a cluster formation and reaction source is employed to study the reactivity of cationic vanadium oxide clusters (VmOn +) toward ethylene (C2H4) in the gas phase. The cationic vanadium oxide clusters with m=1-10 and n=1-26 (depending on m) are generated by reaction of laser ablation created vanadium plasma with O2 in a supersonic expansion and then reacted with the ethylene in a flow tube reactor. Hydrogen atoms are attached in most of the oxygen saturated clusters (2n≥5m) in our experimental condition. The reactivity of VmOn + toward C2H4 is usually higher than that of hydrogen containing clusters, VmOnH2x +. Larger clusters show less reactivity than smaller ones. Most of the observed products are in the forms of VmOnC2H4 + and VmOnH2xC2H4 + due to direct association. C2H4 clustering products ((C2H4)n +, n=2-6) are also observed.

The uptake of 2-methyl-3-buten-2-ol into aqueous mixed solutions of sulfuric acid and hydrogen peroxide

Multiphase acid-catalyzed oxidation with hydrogen peroxide (H(2)O(2)) has been suggested recently to be a potential route to SOA formation from isoprene and its gas-phase oxidation products, the kinetics and chemical mechanism of this process have not been well-known yet. In this work, the uptake of 2-methyl-3-buten-2-ol (MBO), an important biogenic hydrocarbon and structurally similar to isoprene, into aqueous mixed solutions of H(2)O(2) and sulfuric acid (H(2)SO(4)) was performed using a rotated wetted-wall reactor coupled to a differentially pumped single-photon ionization time of flight mass spectrometer (RWW-SPI-TOFMS). The reactive uptake coefficients (γ) were acquired for the first time and the reaction pathways were deduced according to products information. The reactive uptake coefficients of MBO into H(2)SO(4)-H(2)O(2) mixed solutions are much greater than that into H(2)SO(4) solutions. Acetaldehyde, acetone and an on-line product, which transformed to isoprene readily in the duration of an off-line experiment, were suggested as products in this process. The further reactions of the carbonyl products can occur in acidic solution, which may play a role in SOA formation. Additionally, in real atmosphere the on-line product is apt to transform to isoprene, an acknowledged precursor of biogenic SOA. Thus, the multiphase acid-catalyzed oxidation of MBO with H(2)O(2) might be a potential contributor to SOA loading.