Electrical Power Generation from the Contrasting Interfacial Activities of Boron- and Nitrogen-Doped Reduced Graphene Oxide Membranes

Water, the medium of life, has also served as a sustainable source of energy for hundreds of years. However, most of the water-based energy harvesting techniques relies either on rapid flow or on the fast evaporation rate of the molecules. Here, the complementary charge transfer activities of boron (B-r-GO) and nitrogen (N-r-GO) doped reduced graphene oxide (r-GO) flakes are exploited to extract energy from serene water resources. B-r-GO and N-r-GO samples prepared by annealing graphene oxide sheets with boric acid and urea were individually coated on cellulose membranes to fabricate B-r-GO/N-r-GO devices, which produces open-circuit voltages up to 570 mV when dipped in water. The power-output were found to be tunable by varying parameters like coating area, dopant amounts, annealing temperature, and ionic conductivity. The potential-drops due to the prolong soaking of B-r-GO/N-r-GO devices (for a few days) can be completely recovered through vacuum drying. In order to open-up the possibility of fabricating wearable energy devices the B-r-GO/N-r-GO samples are also coated on arbitrary substances like jeans cloths. The DFT calculations indicate that compared to N-r-GO, the B-r-GO structure is more stable and has considerably higher charge transfer activity with water molecules.