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

Abstract

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 cm² 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.