Landscapes give latitude to 2-D material designers

Rice, Oak Ridge scientists show growing atom-thin sheets on cones allows control of defects

Hands of Henry” (Nitant Gupta, c. 2017; WS2 on conical canvas)

Rice University researchers have learned to manipulate two-dimensional materials to design in defects that enhance the materials’ properties.

The Rice lab of theoretical physicist Boris Yakobson and colleagues at Oak Ridge National Laboratory are combining theory and experimentation to prove it’s possible to give 2-D materials specific defects, especially atomic-scale seams called grain boundaries. These boundaries may be used to enhance the materials’ electronic, magnetic, mechanical, catalytic and optical properties.

The key is introducing curvature to the landscape that constrains the way defects propagate. The researchers call this “tilt grain boundary topology,” and they achieve it by growing their materials onto a topographically curved substrate — in this case, a cone. The angle of the cone dictates if, what kind and where the boundaries appear.

The research is the subject of a paper in the American Chemical Society journal ACS Nano.

– See more at Rice News

Self-optimizing catalysts for hydrogen evolution on the cover of Nature Energy

Rice, Lawrence Livermore scientists replace expensive platinum for efficient hydrogen production

Scientists at Rice University and the Lawrence Livermore National Laboratory have predicted and created new two-dimensional electrocatalysts to extract hydrogen from water with high performance and low cost.

In the process, they also created a simple model to screen materials for catalytic activity.

Several catalysts were modeled by Rice theoretical physicist Boris Yakobson and lead author Yuanyue Liu, a former graduate student in his lab, and made and tested by Rice materials scientists led by Pulickel Ajayan and Jun Lou. They found the new dichalcogenide catalysts matched the efficiency of platinum — the most common hydrogen evolution reaction (HER) catalyst in water-splitting cells — and can be made at a fraction of the cost.

The study is a cover story in the September issue of Nature Energy.

– See more at Rice News