Scientists study growth pathway of catalyst using X-rays, according to a report published on December 26, 2018.
Although hydrogen fuel cells are a promising technology for the production of clean and renewable energy, commercialization is challenging due to its cost and activity of cathode materials. Most of the fuel cells require expensive platinum-based catalysts for the conversion of renewable fuels into electrical energy.
A new method was developed by the researchers at the University of Akron to synthesize catalysts from a combination of metals—platinum and nickel—that form octahedral (eight-sided) shaped nanoparticles. Scientists identified this catalyst as one of the most efficient replacements for pure platinum. However, they did not understand its growth process in an octahedral shape. Therefore, to better understand the growth process, the researchers collaborated with multiple institutions, including Brookhaven and its NSLS-II.
Researchers used the ultrabright x-rays at NSLS-II and the advanced capabilities of NSLS-II’s In situ and Operando Soft X-ray Spectroscopy (IOS) beamline to reveal the chemical characterization of the catalyst’s growth pathway in real time. Moreover, the results of their study was published in Nature Communications.
A technique called ambient-pressure X-ray photoelectron spectroscopy (AP-XPS) was used by the research team to study the surface composition and chemical state of the metals in the nanoparticles during the growth reaction. Due to the advanced capabilities of IOS, they were able to carry out experiments at gas pressures higher than what is usually possible in conventional XPS experiments. Additional X-ray and electron imaging studies completed at the Advanced Photon Source (APS) at DOE’s Argonne National Laboratory—another DOE Office of Science User Facility—and University of California-Irvine, respectively, complemented the work at NSLS-II.
Zhenmeng Peng, principal investigator of the catalysis lab at the University of Akron said, “This fundamental work highlights the significant role of segregated nickel in forming the octahedral-shaped catalyst. We have achieved more insight into shape control of catalyst nanoparticles. Our next step is to study catalytic properties of the faceted nanoparticles to understand the structure-property correlation.”