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Vital Progress in Multi-scale Design of Energy Materials

Achieved by Dr. Guo in School of Physics

 

In the fields of novel energy and environmental technology, great efforts have been focused on how to find and design highly active, cheap and environmentally friendly catalysts. Recently, core-shell nanoparticles of transition metal alloy have shown remarkable advantage over traditional metal catalysts in applications of photoelectrocatalysis and biomass energy conversion, etc. This is mainly owing to the unique modification of structures and electronic properties by mixing two metals in the nanoparticle. However, due to the complex microstructures of the core-shell nanoparticle, it is very challenging for material design in both experiment and theoretical calculation. Revealing the physical mechanism of the in-situ activity and the active sites in real experimental conditions shall provide notable insights into design and synthesis of catalytic materials.

Recently, Dr. Wei Guo, who is a member of Prof. Yugui Yao’s group in School of Physics, made a vital progress in multi-scale design of energy materials through cooperation with Prof.  Dionisios G. Vlachos in the University of Delaware, USA. By combining density functional theory and kinetic Monte Carlo simulation, they predicted a novel bimetallic multifunctional material, which has sub-monolayer patched atoms of a guest metal onto another host metal. The patched atoms serve as an effective modification of the metal nanoparticle, resulting in activity increased by 2~3 orders of magnitude. The results were just published in Nature Communications, 6, 8619 (2015) on October 7th. 

http://www.nature.com/ncomms/2015/151007/ncomms9619/full/ncomms9619.html

 

As an important industry feed stock, ammonia is often utilized for fertilizer. Meanwhile, ammonia can serve as a fuel provider of on-site COx free hydrogen for fuel cells. In addition, ammonia decomposition is a prototypical reaction of structure sensitivity and is ideal for understanding microstructure and active site in material design. The work by Dr. Guo and Prof. Vlachos indicates that, by depositing Ni patches on Pt nanoparticle, multifunctional catalysis is achieved as such: Ni terrace sites on Pt catalyze ammonia decomposition and Ni step edges catalyze N-N association after surface N spills over to Ni step edge. Actually, the patched bimetallic surface offers not only better performance, but also ease of synthesis. Their findings open up a brand new window for material design requiring multiple active sites: scientists may boost the performance of materials by purposely making use of the inevitable nonidealities in real materials to obtain multi-functionality for complicated reactions and applications.

Release date:2015-10-27