纳米金刚石/竖立石墨烯复合三维电极的制备及电化学性能研究

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

金刚石/石墨烯复合电极因能发挥金刚石组分的低背景电流和宽电势窗口,且兼具石墨组分的高电化学活性,引起了人们的广泛关注.本文采用热丝化学气相沉积方法,通过调控短时生长时间,在纳米金刚石单颗粒层表面的竖立石墨烯片中嵌入纳米金刚石,形成复合三维电极.结果表明,当竖立石墨烯片顶部生长了纳米金刚石时,电极显示较宽的电势窗口(3.59 V)和极低的背景电流(1.27 mA/cm^(2)),片层顶部少层石墨包覆纳米金刚石晶粒的复合结构是拓宽电势窗口和降低背景电流的关键.随着生长时间延长,竖立片层长大,纳米金刚石晶粒嵌入到片层中,构建了新型的纳米金刚石/石墨烯复合竖立片层结构;有序的石墨结构使得电化学活性面积增大为677.19μC/cm^(2)和比电容增至627.34μF/cm^(2),石墨组分增多使得电势窗口变窄,嵌入片层中的纳米金刚石有效地降低背景电流.本研究提供了一种热丝化学气相沉积方法制备纳米金刚石/石墨烯复合三维电极的新方法,并为充分发挥金刚石/石墨烯复合薄膜的协同效应提供了一种新思路.

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^(2))when nano-diamond crystals grow on the top of the vertical graphene sheet.The composite structure of nanodiamond 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^(2) and the specific capacitance to 627.34 μF/cm^(2).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.