The direct growth of a WO3 nanosheet array on a transparent conducting substrate for highly efficient electrochromic and electrocatalytic applications

A vertically aligned hierarchical WO3 nanosheet array on a transparent conducting substrate is produced via a template-free and capping-agent-free hydrothermal method. Due to its high porosity among the nanosheets and good contact with the conductive substrate, the WO3 nanosheet film exhibits advantageous electrochemical abilities. For example, fast switching speed (5.2 and 2.2 s for coloration and bleaching, respectively), significant optical modulation (62% at 633 nm and 67% at 2000 nm), high coloration efficiency of 55.6 cm(2) C-1 at 700 nm and excellent cycling stability (95.4% after 3000 cycles) are achieved for the WO3 nanosheet array film in electrochromic application. In addition, the nanosheet film also shows outstanding electrocatalytic ability for chemical reduction of H2O2.