Duan group collaboration featured in ACS Central Science

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The team reported on a new on-chip “tool” that helps to “see” & identify the key process that hinders the performance of catalyst used in fuel cells.

The tool will help scientists find respective solutions more efficiently.

The work was led by Xiangfeng Duan, a UCLA professor of chemistry and biochemistry, and Yu Huang, a UCLA professor of materials science and engineering.

Mengnin DingThe lead author of the study is Mengning Ding (pictured right), a former UCLA CNSI postdoctoral fellow advised by Huang and Duan, now a professor of chemistry at Nanjing University, China. Other study authors are UCLA graduate students and postdoctoral researchers in Duan and Huang’s research groups and researchers from King Saud University, Saudi Arabia.

The study titled “On-Chip in Situ Monitoring of Competitive Interfacial Anionic Chemisorption as a Descriptor for Oxygen Reduction Kinetics” was published in the May 23, 2018 issue of ACS Central Science.

By Prof. Mengning Ding:

Research image

For many sustainable energy technologies, such as fuel cells, batteries, and artificial photo-synthesis, electrocatalysis plays a central role. It has become generally accepted that being able to “see” the electrochemical reactions at molecular level is key to help scientists and engineers better understand, and then achieve major breakthroughs in the development of next-generation energy technologies. This is yet extremely challenging due to the lack of in situ analytical tools (spectroscopic methods that can efficiently access the electrochemical interfaces between solid electrodes and liquid electrolytes while providing selective and accurate signals). 

A research team led by Prof. Xiangfeng Duan has spent several years working on the development of  an overall different tool,

using on-chip nano-electronic signaling approach, which is typically applied in semiconductor industry, to help “see” the specific electrochemical interfaces (a process that highly matters to the performance of the materials) while the catalytic process is in action. In this recent study, the UCLA team has used the strategy to visualize a classic interfacial process, anionic adsorptions on platinum surface, and hence identified it as a descriptor for the oxygen reduction kinetics. These findings provide the UCLA team with intriguing fundamental insights into the surface poisoning of reaction kinetics by trace anionic species, and with this efficient way of studying tool, researchers were able to find solutions to increase the poisoning resistance of the fuel cell catalyst (or impurity tolerance) of the fuel cell catalysts, which has been a serious issue for the real-world fuel cell devices (linked to device durability). With many successful applications, the researchers believe such nano-electronic method could further become a general approach to help uncover broader governing principles in the field of electrocatalysis.
A previous report of the development of our method was published in 

Nature Communications

 in 2015. 
The former work is the demonstration of the working principles of the newly developed tool, electrical transport spectroscopy (ETS), whereas the uniqueness of this work is  the use of the ETS tool to actually “see” a highly important, practically relevant, yet technically much more challenging interfacial process (anions like chloride do not generate much spectroscopic features, which makes the characterization of them on the surface very difficult), which lead us to find two ways that could potentially lead to more poisoning tolerant fuel cell devices with better durability.

To learn more about the Duan group’s research, visit their website.