Researchers have found a new technique that can be used to characterize individual noble-metal-free nanoparticle catalysts. The particles can be an inexpensive replacement for precious metal catalysts to obtain hydrogen from water through the process of electrolysis, but because they are so small, it becomes challenging to determine their properties. Professor Wolfgang Schuhmann, Center for Electrochemistry, Ruhr-Universität Bochum, says that to develop efficient nanoparticles, it is important to decipher how the activity and structure of individual particles and small particle groups are connected. The team included the researchers Tsvetan Tarnev and Dr. Harshitha Barike Ayappa from Bochum, along with Professor Corina Andronescu, University of Duisburg-Essen, and other colleagues. The team’s paper has been published in the journal Angewandte Chemie.
There exist just a few techniques that can be used to measure the catalytic activity of single or multiple nanoparticles. Schuhmann adds that the currents that have to be measured are diminutive, and to correctly measure them, it is necessary to have at least a single or a few nanoparticles. The team successfully demonstrated that such analyses are also achievable with high throughput, for instance, with scanning electrochemical cell microscopy. Until now, this method had not been employed for this purpose as the nanoparticles needed to be tested under severe chemical conditions, which gave way to significant measurement inaccuracies. This made it possible to get a reliable interpretation of the results. In the latest study, the researchers fabricated a new reference system for scanning electrochemical cell microscopy. With a stable internal standard, the team eliminated the measurement inaccuracies, enabling long-lasting measurements according to the given conditions with high throughput.
The team made carbon particles using nitrogen and cobalt inclusions on glassy carbon, wherein the particles were present on the surface either as individual particles or a few particles together. With a single experiment, the team was able to use scanning electrochemical cell microscopy to determine the electrochemical activity of the individual as well as the group of particles.