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.