Environmental Molecular Sciences Laboratory

About: Environmental Molecular Sciences Laboratory is a facility organization based out in Richland, Washington, United States. It is known for research contribution in the topics: Mass spectrometry & Ion. The organization has 1471 authors who have published 3010 publications receiving 169961 citations.

Characterization of ambient aerosols in Mexico City during the MCMA-2003 campaign with Aerosol Mass Spectrometry: results from the CENICA Supersite

Abstract: An Aerodyne Aerosol Mass Spectrometer (AMS) was deployed at the CENICA Supersite, during the Mexico City Metropolitan Area field study (MCMA-2003) from 31 March-4 May 2003 to investigate particle concentrations, sources, and processes The AMS provides real time in- formation on mass concentration and composition of the non-refractory species in particulate matter less than 1 µm (NR-PM1) with high time and size-resolution In order to account for the refractory material in the aerosol, we also present estimates of Black Carbon (BC) using an aethalome- ter and an estimate of the aerosol soil component obtained from Proton-Induced X-ray Emission Spectrometry (PIXE) analysis of impactor substrates Comparisons of AMS + BC + soil mass concentration with other collocated particle instruments (a LASAIR Optical Particle Counter, a PM25 Tapered Element Oscillating Microbalance (TEOM), and a PM25 DustTrak Aerosol Monitor) show that the AMS + BC + soil mass concentration is consistent with the total PM25 mass concentration during MCMA-2003 within the combined uncertainties In Mexico City, the organic fraction of the estimated PM25 at CENICA represents, on average, 546% (standard deviation =10%) of the mass, with the rest consisting of inorganic compounds (mainly ammonium ni- trate and sulfate/ammonium salts), BC, and soil Inorganic compounds represent 275% of PM25 ( =10%); BC mass concentration is about 11% ( =4%); while soil represents

Flexible Pillared Graphene-Paper Electrodes for High-Performance Electrochemical Supercapacitors

Abstract: Flexible graphene paper (GP) pillared by carbon black (CB) nanoparticles using a simple vacuum filtration method is developed as a high-performance electrode material for supercapacitors. Through the introduction of CB nanoparticles as spacers, the self-restacking of graphene sheets during the filtration process is mitigated to a great extent. The pillared GP-based supercapacitors exhibit excellent electrochemical performances and cyclic stabilities compared with GP without the addition of CB nanoparticles. At a scan rate of 10 mV s −1 , the specific capacitance of the pillared GP is 138 F g −1 and 83.2 F g −1 with negligible 3.85% and 4.35% capacitance degradation after 2000 cycles in aqueous and organic electrolytes, respectively. At an extremely fast scan rate of 500 mV s −1 , the specific capacitance can reach 80 F g −1 in aqueous electrolyte. No binder is needed for assembling the supercapacitor cells and the pillared GP itself may serve as a current collector due to its intrinsic high electrical conductivity. The pillared GP has great potential in the development of promising flexible and ultralight-weight supercapacitors for electrochemical energy storage.

High-Performance Rh2P Electrocatalyst for Efficient Water Splitting

Abstract: The search for active, stable, and cost-efficient electrocatalysts for hydrogen production via water splitting could make a substantial impact on energy technologies that do not rely on fossil fuels. Here we report the synthesis of rhodium phosphide electrocatalyst with low metal loading in the form of nanocubes (NCs) dispersed in high-surface-area carbon (Rh2P/C) by a facile solvo-thermal approach. The Rh2P/C NCs exhibit remarkable performance for hydrogen evolution reaction and oxygen evolution reaction compared to Rh/C and Pt/C catalysts. The atomic structure of the Rh2P NCs was directly observed by annular dark-field scanning transmission electron microscopy, which revealed a phosphorus-rich outermost atomic layer. Combined experimental and computational studies suggest that surface phosphorus plays a crucial role in determining the robust catalyst properties.

Utilizing Human Blood Plasma for Proteomic Biomarker Discovery

Abstract: Candidate proteomic biomarker discovery from human plasma holds both incredible clinical potential as well as significant challenges. The dynamic range of proteins within plasma is known to exceed 1010, and many potential biomarkers are likely present at lower protein abundances. At present, proteomic based MS analyses provide a dynamic range typically not exceeding ∼103 in a single spectrum, and ∼104−106 when combined with on-line separations (e.g., reversed-phase gradient liquid chromatography), and thus are generally insufficient for low level biomarker detection directly from human plasma. This limitation is providing an impetus for the development of experimental methodologies and strategies to increase the possible number of detections within this biofluid. Discussed is the diversity of available approaches currently used by our laboratory and others to utilize human plasma as a viable medium for biomarker discovery. Various separation, depletion, enrichment, and quantitative efforts as well as rece...

Experimental observation and confirmation of icosahedral W@Au12 and Mo@Au12 molecules.

Abstract: The recently predicted W@Au12 cluster has been observed and probed experimentally using anion photoelectron spectroscopy. It is shown that this unique molecule and its Mo congener indeed possess an icosahedral structure and a large HOMO-LUMO gap. Relativistic density functional theory is used to calculate their geometries, energetics, and energy spectra. The simulated density-of-states spectra are in good agreement with the photoelectron spectra, confirming the icosahedral structure of these complexes.