Low-Thermal-Budget Doping of 2D Materials in Ambient Air Exemplified by Synthesis of Boron-Doped Reduced Graphene Oxide.

Graphene oxide (GO) doping and reduction allow for physicochemical property modification to suit practical application needs. Herein, the challenge of simultaneous low-thermal-budget heteroatom doping of GO and its reduction in ambient air is addressed through the synthesis of B-doped reduced GO (B@rGO) by flash irradiation of boric acid loaded onto a GO support with intense pulsed light (IPL). The effects of light power and number of shots on the in-depth sequential doping and reduction mechanisms are investigated by ex situ X-ray photoelectron spectroscopy and direct millisecond-scale temperature measurements (temperature >1600 °C, < 10-millisecond duration, ramping rate of 5.3 × 105 °C s-1). Single-flash IPL allows the large-scale synthesis of substantially doped B@rGO (≈3.60 at% B) to be realized with a thermal budget 106-fold lower than that of conventional thermal methods, and the prepared material with abundant B active sites is employed for highly sensitive and selective room-temperature NO2 sensing. Thus, this work showcases the great potential of optical annealing for millisecond-scale ultrafast reduction and heteroatom doping of GO in ambient air, which allows the tuning of multiple physicochemical GO properties.