Facile synthesis of ZnO nanorod arrays and hierarchical nanostructures for photocatalysis and gas sensor applications

► Orderly aligned ZnO nanorods can be grown on various substrates without catalysts and seeds through a simple one-step hydrothermal route. ► The prepared ZnO nanostructures exhibited superior photocatalytic activity for decomposing Methyl orange. ► The obtained ZnO nanostructures exhibited excellent sensing performance towards some flammable gases.