Layer-by-layer growth of ultralong ZnO vertical wire arrays for enhanced photoelectrocatalytic activity

We have developed a vapor–liquid–phase combined, layer-by-layer epitaxial growth strategy for fabricating ultralong ZnO one-dimensional vertical arrays. A key point is the activation of the second top epitaxial growth by treating shorter arrays in a growth solution. By alternating solution- and VS-growth steps for three times, we can tune the length of the 1D arrays from 41 to 150 μm. The arrays were found to show an excellent photoelectrocatalytic activity under UV irradiation, higher than that of high-performance TiO2 nanotube arrays.

► We have developed a novel strategy via an alternating VS and solution-growth process for fabricating ultralong ZnO wire arrays with length up to 150 μm. ► ZnO wire arrays show excellent photoelectrocatalytic activity, and the decomposition rate increases with increasing layer number or wire length higher than that of high-performance TiO2 nanotube arrays.