Pacific Northwest National Laboratory

About: Pacific Northwest National Laboratory is a facility organization based out in Richland, Washington, United States. It is known for research contribution in the topics: Catalysis & Aerosol. The organization has 11581 authors who have published 27934 publications receiving 1120489 citations. The organization is also known as: PNL & PNNL.

Low-temperature carbon monoxide oxidation catalysed by regenerable atomically dispersed palladium on alumina

Abstract: Catalysis by single isolated atoms of precious metals has attracted much recent interest, as it promises the ultimate in atom efficiency. Most previous reports are on reducible oxide supports. Here we show that isolated palladium atoms can be catalytically active on industrially relevant γ-alumina supports. The addition of lanthanum oxide to the alumina, long known for its ability to improve alumina stability, is found to also help in the stabilization of isolated palladium atoms. Aberration-corrected scanning transmission electron microscopy and operando X-ray absorption spectroscopy confirm the presence of intermingled palladium and lanthanum on the γ-alumina surface. Carbon monoxide oxidation reactivity measurements show onset of catalytic activity at 40 °C. The catalyst activity can be regenerated by oxidation at 700 °C in air. The high-temperature stability and regenerability of these ionic palladium species make this catalyst system of potential interest for low-temperature exhaust treatment catalysts.

The effect of young biochar on soil respiration

Abstract: The low temperature pyrolysis of organic material produces biochar, a charcoal like substance. Biochar is being promoted as a soil amendment to enhance soil quality, it is also seen as a mechanism of long-term sequestration of carbon. Our experiments tested the hypothesis that biochar is inert in soil. However, we measured an increase in CO2 production from soils after biochar amendment which increased with increasing rates of biochar. The ∂13C signature of the CO2 evolved in the first several days of the incubation was the same as the ∂13C signature of the biochar, confirming that biochar contributed to the CO2 flux. This effect diminished by day 6 of the incubation suggesting that most of the biochar C is slowly decomposing. Thus, aside from this short-term mineralization increasing soil C with young biochar may indeed be a long-term C storage mechanism.

Electrochemically Induced High Capacity Displacement Reaction of PEO/MoS2/Graphene Nanocomposites with Lithium

Abstract: MoS2/PEO/graphene composite is successfully prepared and the discharge mechanism of MoS2 as an anode material for Li-ion batteries has been investigated systematically in this work The simultaneous formation of Li2S and Mo at deep discharge depth has been shown for the first time The deposition of Mo metal with Li residing on the defects after the first discharge increases the intrinsic electronic conductivity of the electrode leading to a superior cycling stability for over 185 cycles After the first discharge the amorphous Mo matrix allows a large amount of Li+ ions to repeatedly deposit and being oxidized during cycling while the transition between Li2S and S contribute to the capacity above 20 V The interactions between as-formed Mo and S prevents the dissolution of the intermediate polysulfide thus providing clues to immobilize the soluble species in a Li-S battery Excellent rate performances are achieved in this MoS2/PEO/graphene composite indicating a fast diffusion path of Li+ ions existing not only in the bulk material but also in the interface between the electrode and the electrolyte

Making Li‐Air Batteries Rechargeable: Material Challenges

Abstract: A Li-air battery could potentially provide three to five times higher energy density/specific energy than conventional batteries and, thus, enable the driving range of an electric vehicle to be comparable to gasoline vehicles. However, making Li-air batteries rechargeable presents significant challenges, mostly related to the materials. Here, the key factors that influence the rechargeability of Li-air batteries are discussed with a focus on nonaqueous systems. The status and materials challenges for nonaqueous rechargeable Li-air batteries are reviewed. These include electrolytes, cathode (electrocatalysts), lithium metal anodes, and oxygen-selective membranes (oxygen supply from air). A perspective for the future of rechargeable Li-air batteries is provided.