High catalytic activity of amorphous/crystalline heterostructures in Au nanoparticles: A theoretical investigation

CH Zhang and ZW Zhang and K Meng and Y Lu and J Rong and Y Wei and YN Zhang and XH Yu and HY Hou, MATERIALS TODAY COMMUNICATIONS, 37, 107190 (2023).

DOI: 10.1016/j.mtcomm.2023.107190

The exploration of highly active and stable catalysts for hydrogen evolution reaction (HER) is the promising solution to the energy crisis, with increasing energy consumption and growing concern about environmental pollution. Recently, amorphous/crystalline (a/c) heterostructures have enabled the catalytic properties to be significantly enhanced due to the strong interfacial electron coupling, realizing the deep optimization of catalytic activity. However, the mechanism of the microscopic catalysis between the active sites and the surrounding ligand is not sufficiently clarified for a/c heterostructure catalysts. Here, Au nanoparticles (AuNPs) with coreshell a/c heterogeneously bound are rationally constructed, whereby the structure- reactivity relationship of AuNPs in the catalytic process and their electronic properties at the surface-active site are thoroughly inspected utilizing molecular dynamics and density-functional tight- binding. As the temperature increases, the size effect of 4 nm AuNPs gradually masks their electronic effect. And the formation free energy of H* reaches the highest catalytic performance of-0.41 eV at 900 K. The introduction of the amorphous phase makes it possible to increase the proportion of active sites with nine coordination numbers from 1 % to 22 %, decreasing the energy barrier of the reaction intermediate and increasing the catalytic activity. Furthermore, the synergy between the amorphous and crystalline phases lowers the D-band center due to the extension of the amorphization, and reaches the maximum change at 900 K, reducing the D-band center of the HER from-0.40 eV (0 K) to-0.48 eV. This investigation delivers explicit insights into the action of a/c heterostructures in optimizing catalytic activity and explores innovative ideas for devising efficient and stable nanoparticle catalysts.

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