O2-Induced Segregation as an Efficient Tool for Fine-Tuning the Intermetallic Pd-In/HOPG Surface Structure
Bimetallic catalysts often demonstrate improved catalytic selectivity, activi-ty and stability in comparison with monometallic ones. The formation of the specific surface composition of bimetallic particles plays a crucial role in the synergistic effects. The chemical composition and structure of active sites are determined at the preparation step. However, it can be deliberately modified by specific treatment of the surface sample in the reactive gas atmosphere for fine surface composition tuning and consequent optimization of catalytic properties in low temperature reactions [1, 2].
Model bimetallic Pd-In/HOPG catalysts with size-selected particles and different metal atomic ratios have been prepared using the successive thermal vacuum metal deposition. Intermetallic Pd-In nanoparticles formation and their post-synthesis transformation upon oxidative treatments have been investigated by the combination of synchrotron radiation-based X-ray photoelectron spectroscopy and scanning tunneling microscopy. It was shown that the reversible RedOx transformation Pd-Inintermet ↔ Pd° + InOx can be efficiently used to deliberately tune the nanoparticles surface composition/structure and respective catalytic characteristics.
We are grateful to the German-Russian Interdisciplinary Scientific Center (G-RISC) funded by the Federal Ministry of Foreign Affairs of Germany via the German Academic Exchange Service (DAAD).
The authors would like to thank the Russian Science Foundation (Grant No. 19-13-00285) for the financial support of this work.