High-index crystal plane of ZnO nanopyramidal structures: Stabilization, growth, and improved photocatalytic performance

While the low-index planes of Wurtzite ZnO, such as {0001} and {10 (1) over bar0} are well-understood, the high-index crystal surfaces have not yet been thoroughly researched despite possessing structural characteristics that make them suitable for many important surface chemistry processes. The high surface energy of high-index ZnO crystal surfaces makes synthesis challenging to achieve due to their instability during crystal growth. In this work, we present a combined experimental and theoretical analysis of growth and photocatalytic activity of ZnO high-index crystal facets. Density functional theory calculations are performed to determine the thermodynamic conditions necessary to stabilize the high-energy semi-polar {11 (2) over bar2} facets of pyramidal ZnO nanostructures grown via chemical vapor deposition (CVD). The photocatalytic properties of as-synthesized nanopyramidal structures for water splitting applications showed a 73% improved photocatalytic performance compared to CVD-grown hexagonal ZnO nanorods with dominating low-index {10 (1) over bar0} facets.

Automated summary

The high-index crystal surfaces of ZnO have structural characteristics suitable for important surface chemistry processes, and density functional theory calculations can determine the thermodynamic conditions necessary for their stabilization. Synthesized ZnO nanopyramidal structures show significantly improved photocatalytic performance for water splitting applications compared to CVD-grown hexagonal ZnO nanorods with low-index facets.