United States Department of Energy

About: United States Department of Energy is a government organization based out in Washington D.C., District of Columbia, United States. It is known for research contribution in the topics: Catalysis & Coal. The organization has 13656 authors who have published 14177 publications receiving 556962 citations. The organization is also known as: DOE & Department of Energy.

Solidification microstructures: A conceptual approach

Abstract: Detailed theoretical models have been developed in the literature to correlate microstructural characteristics as a function of processing parameters. These results are examined with a broad perspective to show that various laws for microstructural transitions and microstructural spacings can be represented in terms of three simple characteristic lengths of the important physical processes. Initially, the important physical processes of solute and thermal transport and capillarity effect are considered, and they are related to the microstructural lengths such as dendrite tip radius, primary and secondary spacing, and eutectic spacing. It is shown that these microstructural lengths are simply given by the geometric mean of the characteristic lengths of physical processes that are important in a given problem. New characteristic lengths that become important under rapid solidification are then developed, and how these characteristic lengths influence microstructural transition and microstructural scales is also discussed.

Defect-Rich 2D Material Networks for Advanced Oxygen Evolution Catalysts

Abstract: A versatile and straightforward room-temperature strategy is demonstrated to synthesize boundary defect-rich ultrathin transition metal hydroxide nanosheet networks by in situ etching of a cobalt metal–organic framework (Co-MOF, ZIF-L-Co). The resultant defect-rich ultrathin Co(OH)2 (D-U-Co(OH)2) nanoarray is one of the most active monometal-based oxygen evolution catalysts to date. Its activity is 3–4 times higher than that of the commercial RuO2 and superior to that of the reported exfoliated bimetallic catalysts. Co-MOF can also be grown on various substrates, and the chemical composition of the defect-rich 2D materials is tunable by changing the metal ions in the etchants. Owing to these merits of the unique synthesis route, our work provides an opportunity for synthesizing advanced nanomaterials that are difficult to get access to by conventional methods.