Au₉ nanocluster adsorption and agglomeration control through sulfur modification of mesoporous TiO₂

In the present work phenyl phosphine-protected Au₉ nanoclusters were deposited onto (3-mercaptopropyl) trimethoxysilane (MPTMS) modified and unmodified mesoporous screen printed TiO₂. The removal of the cluster ligands by annealing was applied to enhance the interaction between Au cluster cores and semiconductor surfaces in the creation of efficient photocatalytic systems. The heat treatment could lead to undesired agglomeration of Au clusters, affecting their unique properties as size specific clusters. To address this challenge, the semiconductor surfaces were modified by MPTMS. Characterization techniques confirm the effectiveness of the modification processes, and XPS demonstrates that S functionalized MTiO₂ is more efficient than MTiO₂ in increasing Au₉ NCs adsorption by a factor of 10 and preventing Au cluster agglomeration even after annealing. Overall, this work contributes valuable insights into photocatalytic systems through controlled modification of semiconductor surfaces and Au nanocluster deposition.