Interfaces in Nanocrystalline Oxide Materials: From Powders Toward Ceramics

<p>Layered Li<i><sub>x</sub></i>MO<sub>2</sub> materials, a new class of high-entropy oxides, have been synthesized by nebulized spray pyrolysis. Specifically, the lattice structure of Li(Ni<sub>1/3</sub>Mn<sub>1/3</sub>Co<sub>1/3</sub>)O<sub>2</sub> (NCM111) cathode material has been replicated successfully while increasing the number of cations in equimolar proportions, thereby allowing transition to high-entropy oxide materials.</p>

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Towards a Design of Active Oxygen Evolution Catalysts: Insights from Automated Density Functional Theory Calculations and Machine Learning

10.26434/chemrxiv.7926869 ◽

2019 ◽

Author(s):

Seoin Back ◽

Kevin Tran ◽

Zachary Ulissi

Keyword(s):

Machine Learning ◽

Oxygen Evolution ◽

Active Sites ◽

Density Functional ◽

Chemical Space ◽

Density Functional Theory Calculations ◽

Catalyst Design ◽

Transition Metal Catalysts ◽

Oxide Materials ◽

Design Strategies

<div> <div> <div> <div><p>Developing active and stable oxygen evolution catalysts is a key to enabling various future energy technologies and the state-of-the-art catalyst is Ir-containing oxide materials. Understanding oxygen chemistry on oxide materials is significantly more complicated than studying transition metal catalysts for two reasons: the most stable surface coverage under reaction conditions is extremely important but difficult to understand without many detailed calculations, and there are many possible active sites and configurations on O* or OH* covered surfaces. We have developed an automated and high-throughput approach to solve this problem and predict OER overpotentials for arbitrary oxide surfaces. We demonstrate this for a number of previously-unstudied IrO2 and IrO3 polymorphs and their facets. We discovered that low index surfaces of IrO2 other than rutile (110) are more active than the most stable rutile (110), and we identified promising active sites of IrO2 and IrO3 that outperform rutile (110) by 0.2 V in theoretical overpotential. Based on findings from DFT calculations, we pro- vide catalyst design strategies to improve catalytic activity of Ir based catalysts and demonstrate a machine learning model capable of predicting surface coverages and site activity. This work highlights the importance of investigating unexplored chemical space to design promising catalysts.<br></p></div></div></div></div><div><div><div> </div> </div> </div>

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Processing and Deposition of Nanocrystalline Oxide Composites for Thermal Barrier Coatings

10.21236/ada383370 ◽

2000 ◽

Author(s):

Jackie Y. Ying

Keyword(s):

Thermal Barrier Coatings ◽

Thermal Barrier ◽

Barrier Coatings ◽

Oxide Composites ◽

Nanocrystalline Oxide

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