Reduced graphene oxide coupled with g-C3N4 nanodots as 2D/0D nanocomposites for enhanced photocatalytic activity

Abstract

Photocatalytic degradation of organic pollutants requires photocatalysts with superior separation/transfer efficiency of photo-generated electron-hole pairs charge separation ability and broad visible-light adsorption region. 2D Reduced graphene oxide (RGO) coupled with 0D g-C3N4 nanodots (CNDs) as a 2D/0D type of heterojunction photocatalysts were successfully fabricated via a hydrothermal approach. The ultrasmall CNDs were uniformly dispersed on the RGO nanosheets which induced a point contact region in the heterojunction interface, resulting in quicker diffusion from the interior to the surface. In addition, the introduction of RGO narrowed the band gap from 2.8 eV (CND) to 2.6 eV (composite), which showed good photo-response in visible light region. The as-obtained nanocomposites of RGO-CNDs exhibited significantly enhanced visible-light-driven photocatalytic performance (4.5 fold times higher than pure CNDs) during the Methylene blue (MB) degradation. What is more, excellent photostability could be achieved by the composite (nearly 90% after 5 cycles). The enhanced photocatalytic activity was attributed to the enhanced surface area (by RGO), increased active sites (2D/0D structure), enhanced visible light absorption and effective charge separation.