Preparation and electrochemical properties of nano-diamond/vertical graphene composite three-dimensional electrodes

Abstract

Diamond/graphene composite three-dimensional electrode has attracted extensive attention because of its low background current, wide potential window from diamond component, and high electrochemical activity from graphite component. In this work, by using the hot wire chemical vapor deposition method, nano diamonds are embedded in the vertical graphene sheet on the surface of single particle layer of nano diamond by regulating the short-term growth time to form a composite three-dimensional electrode. The results show that the electrode exhibits a wide potential window (3.59 V) and a very low background current (1.27 mA/cm<sup>2</sup>) when nano-diamond crystals grow on the top of the vertical graphene sheet. The composite structure of nano-diamond crystals coated with graphite on the top of the graphene sheet is the key to broadening the potential window and reducing the background current. With the increase of growth time, the vertical graphene sheet grows and nano-diamond grains are embedded into the lamellae, and a novel nano-diamond/graphene composite vertical lamellae structure is constructed. The ordered graphite structure increases the electrochemical active area to 677.19 μC/cm<sup>2</sup> and the specific capacitance to 627.34 μF/cm<sup>2</sup>. The increase of graphite components makes the potential window narrow, and the embedded nano-diamond crystals effectively reduce the background current. This study provides a new method for preparing three-dimensional nanodiamond/graphene composite electrodes by hot wire chemical vapor deposition, and provides a new idea for fully exploiting the synergistic effect of diamond/graphene composite films.