Influence of Lattice Ordering on the Catalytic Activity of Bimetallic Nanoparticles: Structure Matters!
With rising fossil fuel prices and worsening air quality, scientific research for alternative and sustainable energy conversion techniques has become an imminent necessity. Among these techniques, fuel cells that convert chemical energy into electricity have emerged as one of the most prominent options owing to high energy efficiency, low emissions and noise levels, as well as modular structure.1 Electrochemical oxidation of fuels such as methanol, ethanol, formic acid, etc. (referred to as small organic molecules or SOMs) needs a stable and highly active catalyst to lower the activation energy that is measured as “overpotential”. Precious metal based bimetallic or multi-metallic nanoparticles are one of the most effective class of catalysts in this respect. However, they suffer from a severe drawback known as “catalyst poisoning” caused by the strong metal-ligand binding with various reaction intermediates.2 Use of various catalyst support may alleviate this problem to a great extent, but homogeneous distribution of an active catalyst on a support may prove to be a challenging task at larger scale.3
In this seminar, I will talk about unsupported intermetallic nanoparticles that have high intrinsic catalytic activity owing to their ordered crystal structure. I will discuss the role of uniform surrounding of the active sites by catalytically “inactive” atoms in two different systems – Ag3In and Pd2Ge nanoparticles used respectively for reduction of an organic molecule and electrochemical oxidation of ethanol.4,5 I will also stress on the importance of lattice defects within the ordered crystal structure of the nanoparticles toward its catalytic activity.
1. Staffell, I., Scamman, D.; Velazquez, A. A.; Balcombe, P.; Dodds, P. E.; Ekins, P.; Shah, N.; Ward, K. R. Energy Environ. Sci. 2019, 12, 463-491
2. Zhou, M.; Li, C.; Fang, F. Chem. Rev. 2021 121 (2), 736-795
3. Ramani, S.; Sarkar, S.; Vemuri, V.; Peter S. C. J. Mater. Chem. A 2017,5, 11572-11576
4. Sarkar, S.; Balisetty, L.; Shanbogh, P. P.; Peter, S. C. J. catal. 2014, 318, 143-150
5. Sarkar, S.; Jana, R.; Suchitra; Waghmare, U. V.; Kuppan, B.; Sampath, S.; Peter. S. C. Chem. Mater. 2015, 27 (21), 7459-7467