“…For the unreduced system, there is a major peak in the high-frequency region at 3700 cm –1 and a very broad intensity within the 3200–3500 cm –1 range with a minor peak at 3375 cm –1 . In the literature, this peak around 3700 cm –1 is typically attributed to dangling OH bonds pointing toward the air–water interface 50 , 53 , 59 , 97 − 99 or the graphene–water interface, 100 whereas the range between 3200 and 3500 cm –1 is typically attributed to hydrogen-bonded OH bonds (from water and hydroxyl groups) whether pointing away from or toward the interface. 50 , 53 , 59 , 97 − 99 , 101 − 103 After 10 min of reduction, one can see the disappearance of the 3700 cm –1 peak, a growth of a peak around 3500 cm –1 , and a specific peak growing at 2900 cm –1 , which can be attributed to methine groups resulting from the reduction of the graphene oxide.…”