Shultz-Johnson, L.R.; Rahmani, A.; Frisch, J.; Hsieh, T.E.; Hu, L.; Sosa, J.; Davy, M.; Xie, S.; Beazley, M.J.; Gao, Z.; Golvari, P.; Wang, T.H.; Ong, T.G.; Rudawski, N.G.; Liu, F.; Banerjee, P.; Feng, X.; Bär, M.; Jurca, T.: Modifying the Substrate-Dependent Pd/Fe2O3 Catalyst-Support Synergism with ZnO Atomic Layer Deposition. ACS Applied Materials & Interfaces 16 (2024), p. 39387-39398
10.1021/acsami.4c01528
Abstract:
Low-loading Pd supported on Fe2O3 nanoparticles was synthesized. A common nanocatalyst system with previously reported synergistic enhancement of reactivity that is attributed to the electronic interactions between Pd and the Fe2O3 support. Fe2O3-selective precoalescence overcoating with ZnO atomic layer deposition (ALD), using Zn(CH2CH3)2 and H2O as precursors, dampens competitive hydrogenation reactivity at Fe2O3-based sites. The result is enhanced efficiency at the low-loading but high reactivity Pd sites. While this increases catalyst efficiency toward most aqueous redox reactions tested, it suppresses reactivity toward polyaromatic core substrates. X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS) show minimal electronic impacts for the ZnO overcoat on the Pd particles, implying a predominantly physical site blocking effect as the reason for the modified reactivity. This serves as a proof-ofconcept of not only stabilizing supported nanocatalysts but also altering reactivity with ultrathin ALD overcoats. The results point to a facile ALD route for selective enhancement of reactivity for low-loading Pd-based supported nanocatalysts.