▎ 摘　　要

Using solid CO2 (dry ice) as the carbon source, few layer graphene sheets were synthesized by reduction of CO2 with calcium hydride under shock wave loading. In addition, by adding ammonium nitrate to the reaction system, nitrogen-doped graphene material was formed in this one-step shock treatment. The recovered samples were characterized using various techniques such as transmission electron micro-scopy, scanning electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy, and therein the nitrogen-doped graphene was demonstrated to act as a metal-free electrode with an efficient electrocatalytic activity toward oxygen reduction reaction in alkaline solution. This work provides an innovative route for producing one of the most promising carbon nanostructures by employing CO2 as a raw material which is popularly known as the greenhouse gas. (C) 2017 Elsevier Ltd. All rights reserved.