Chemistry Division, U.S. Naval Research Laboratory , Washington, D.C. 20375, United States.
Electronic Science and Technology Division, U.S. Naval Research Laboratory , Washington, D.C. 20375, United States.
Langmuir. 2017 Dec 5;33(48):13749-13756. doi: 10.1021/acs.langmuir.7b03596. Epub 2017 Nov 17.
We show that dehydrogenation of hydrogenated graphene proceeds much more slowly for bilayer systems than for single layer systems. We observe that an underlayer of either pristine or hydrogenated graphene will protect an overlayer of hydrogenated graphene against a number of chemical oxidants, thermal dehydrogenation, and degradation in an ambient environment over extended periods of time. Chemical protection depends on the ease of oxidant intercalation, with good intercalants such as Br demonstrating much higher reactivity than poor intercalants such as 1,2-dichloro-4,5-dicyanonbenzoquinone (DDQ). Additionally, the rate of dehydrogenation of hydrogenated graphene at 300 °C in H/Ar was reduced by a factor of roughly 10 in the presence of a protective underlayer of graphene or hydrogenated graphene. Finally, the slow dehydrogenation of hydrogenated graphene in air at room temperature, which is normally apparent after a week, could be completely eliminated in samples with protective underlayers over the course of 39 days. Such protection will be critical for ensuring the long-term stability of devices made from functionalized graphene.
我们发现，对于双层体系，氢化石墨烯的脱氢过程比单层体系慢得多。我们观察到，无论是原始石墨烯还是氢化石墨烯的底层都会保护覆盖层的氢化石墨烯免受多种化学氧化剂、热脱氢和在环境中的降解，这种保护作用可以持续很长时间。化学保护取决于氧化剂插入的容易程度，具有良好插入能力的试剂，如 Br，比具有较差插入能力的试剂，如 1,2-二氯-4,5-二氰基苯醌 (DDQ)，表现出更高的反应性。此外，在保护性石墨烯或氢化石墨烯底层的存在下，氢化石墨烯在 300°C 的 H/Ar 中的脱氢速率降低了约 10 倍。最后，在室温下空气中氢化石墨烯的缓慢脱氢，通常在一周后就会出现，但在具有保护性底层的样品中，可以在 39 天的时间内完全消除。这种保护对于确保由功能化石墨烯制成的器件的长期稳定性至关重要。
