We describe the direct electro-chemical reduction of graphene oxide to graphene from aqueous suspension by applying reduction voltages exceeding —1.0 to —1.2 V. The conductivity of the deposition medium is of crucial importance and only values between 4-25 mS cm~(-1) result in deposition. Above 25 mS cm~(-1) the suspension de-stabilises while conductivities below 4 mS cm~(-1) do not show a measurable deposition rate. Furthermore, we show that deposition can be carried out over a wide pH region ranging from 1.5 to 12.5. The electro-deposition process is characterised in terms of electro-chemical methods including cyclic voltammetry, quartz crystal microbalance, impedance spectroscopy, constant amperometry and potentiometric titrations, while the deposits are analysed via Raman spectroscopy, infra-red spectroscopy, X-ray photoelectron spectroscopy and X-ray diffractometry. The determined oxygen contents are similar to those of chemically reduced graphene oxide, and the conductivity of the deposits was found to be ～20 S cm~(-1).
展开▼
机译：我们描述了通过施加超过-1.0至-1.2 V的还原电压将环氧乙烷从水悬浮液中直接电化学还原为石墨烯。沉积介质的电导率至关重要，其介电常数只有4-25 mS cm〜（- 1）导致沉积。高于25 mS cm〜（-1）时，悬浮液失稳，而低于4 mS cm〜（-1）的电导率则无法显示可测量的沉积速率。此外，我们表明可以在1.5至12.5的宽pH范围内进行沉积。电沉积过程的特征在于电化学方法，包括循环伏安法，石英晶体微天平，阻抗谱，恒定安培法和电位滴定法，同时通过拉曼光谱，红外光谱，X射线光电子能谱分析沉积物。和X射线衍射仪。测定的氧含量与化学还原的氧化石墨烯的氧含量相似，沉积物的电导率约为20 S cm〜（-1）。
展开▼
