Monash University, School of Chemistry, Clayton, 3800, Vic, Australia.
Phys Chem Chem Phys. 2012 Oct 28;14(40):14034-40. doi: 10.1039/c2cp42385e. Epub 2012 Sep 19.
We describe for the first time the electrochemical co-deposition of composites based on a reactive base metal and graphene directly from a one-pot aqueous mixture containing graphene oxide and Zn(2+). In order to overcome stability issues the Zn(2+) concentration was kept below a critical threshold concentration, ensuring stable graphene oxide suspensions in the presence of cationic base metal precursors. This approach ensures the compatibility between the cationic base metal precursor and graphene oxide, which is more challenging compared to previously reported anionic noble metal complexes. Spectroscopic evidence suggests that the reason for destabilisation is zinc complexation involving the carboxylate groups of graphene oxide. The composition of the electrodeposited co-composites can be tuned by adjusting the concentration of the precursors in the starting mixture. The nano-composites show zinc particles (<3 nm) being uniformly dispersed amongst the graphene sheets. It is also demonstrated that the composites are electrochemically active and suitable for energy storage and energy conversion applications. However, a factor limiting the discharge efficiency is the reactivity of the base metal (low reduction potential and small particle size) which undergoes rapid oxidation when exposed to aqueous electrolytes.
我们首次描述了基于反应性基础金属和石墨烯的复合材料的电化学共沉积，直接从含有氧化石墨烯和 Zn(2+)的一锅式水溶液混合物中进行。为了克服稳定性问题，将 Zn(2+)浓度保持在临界阈值浓度以下，以确保在阳离子基础金属前体存在的情况下氧化石墨烯悬浮液稳定。与以前报道的阴离子贵金属配合物相比，这种方法确保了阳离子基础金属前体与氧化石墨烯之间的兼容性，这更具挑战性。光谱证据表明，不稳定的原因是涉及氧化石墨烯的羧酸盐基团的锌络合。通过调整起始混合物中前体的浓度，可以调整共电沉积复合材料的组成。纳米复合材料显示锌颗粒（<3nm）均匀分散在石墨烯片之间。还证明了这些复合材料具有电化学活性，适用于储能和能量转换应用。然而，限制放电效率的一个因素是基础金属的反应性（还原电势低和颗粒尺寸小），当暴露于水基电解质时，基础金属会迅速氧化。
