Nonconventional nucleation and growth of Au nanoparticles with improved adhesion on oxygen-excessive oxide surfaces

Controlling the number and size of nanoparticles on oxides is essential for manipulating the chemical and physical properties of Au to manifest its catalytic and sensing activities. This task requires a drastic deviation from the current understanding of the inherent nucleation behavior of Au nanoparticles weakly adhered on oxides. Herein, we report experimental and computational evidence supporting the effectiveness of incorporating excessive atomic O at ZnO surfaces on enhancing the adhesion of Au - ZnO. This result is highly contrary to current beliefs, emphasizing the advantage of O-deficient oxide surfaces for enhancing the nucleation. The use of atomic O-excessive ZnO surfaces facilitated the implementation of extremely high nucleation densities (>4 ? 1012 cm- 2) of Au nanoparticles, primarily with reduced diameters of 2?3 nm. These structural features were primarily attributed to the reduction in the free energy at the Au - ZnO interface due to the diffusion and participation of atomic O in Au oxidation. This result offers new insights into the crucial role played by atomic O in enhancing the adhesion of Au with oxides and the development of unique structural features of Au nanoparticles.