“…For instance, graphene was used in: (i) nano-electronics (as MOSFET 22 ), (ii) photonics and optoelectronics (ranging from solar cells, LEDs, touch screens, photo-detectors, to ultrafast lasers 23 ), (iii) Spintronics, 24 and (iv) gas sensing. 5,25,26 In this latter application, graphene can be functionalized and reached the stage to compete with the oxides (such as SnO2, TiO2 and ZnO) and to become future leading material in terms of sensitivity and selectivity towards certain gases.…”