Direct growth of graphene nanowalls on silica for high-performance photo-electrochemical anode

Recently, graphene-like nanofilm materials have attracted extensive attention as the fundamental building blocks for potential applications in optoelectronic devices. Here, we developed a simple and versatile technique to directly produce high-quality graphene nanowalls on silica substrate without any catalyst and post-transfer. It shows that the entire surface of silica substrate is fully covered with continuous graphene nanowalls with well-connected network. Moreover, the prepared optical films exhibit excellent optical absorption with a high absorbance of 95% at a wide range of waveband from visible to near infrared. Such a three dimensional film material with super-large surfaces and outstanding optical properties is further decorated with CdTe nanofilm and used as a photo-electrochemical working electrode. The prepared electrode exhibits a fast photo-responsive behavior with high photo-current density up to 3 mA/cm2. Our study identifies that graphene nanowalls served as an excellent transfer black body can enhance the photo-electrochemical performance of electrode when it is sensitized with semiconductor nanofilms.