Is graphene a combustible material? Various sources such as https://news.ycombinator.com/item?id=7679154 speculate that graphene will combust at higher temperatures.

Is this true? Is the flash point/ temperature of combustion for graphene known?
Graphene combusts at 620 K. See http://pubs.acs.org/doi/abs/10.1021/jp410044v.

It is postulated that it burns at this temperature "because of a large interlayer spacing of graphene sheets (i.e., 5.1 Å)".