▎ 摘　　要

Nucleotide(s) have provided environmentally benign natural innovative molecules for performing the simultaneous reduction and functionalization of GO to yield binary heteroatom(s), i.e., N, P co-doped reduced porous graphene oxide nanohybrids. The incorporation of N and P into the rGO microstructure was revealed by the HR-TEM analysis of the fringes observed along the edges of the nanohybrids, depicting differing interlayer spacings of 0.38 and 0.42 nm, respectively, with the formation of the new bonds, C-N, P-C and P-O-C in N, P-rGO and the creation of more defects in the rGO lattice, as shown by IR and XPS, and Raman spectroscopy, respectively. The electrochemical performance of the binder-free aqueous symmetric supercapacitor (SSC), designed by employing 5 '-adenosine monophosphate (5 '-AMP)-mediated N, P co-doped rGO as an electrode material, demonstrated excellent electrochemical performance in K2SO4 (0.5 m) and NaClO4 (17 m) referred to as salt-in-water (SIW) and water-in-salt (WIS) electrolytes, respectively. In these electrolytes, the cell voltages and energy density (W h kg(-1)) at power density (W kg(-1)) were observed to be 2.6 V, 37.7 @ 521.7 and 2.8 V, 59.2 @ 489.6 respectively. Interestingly, SO42- anions exhibited a better chaotropic nature as compared to NO3- anions reversing the previous findings. Further, K+ ions containing electrolytes were found to be more effective in improving the electrochemical performance as compared to those of Na+ ions containing electrolytes. The high energy storage capability of SSC in the WIS electrolyte was also demonstrated by forming a tandem device by joining three such cells in series, which exhibited an increased output voltage of 8.4 V with long-term cyclic stability as well as by the illumination of 114 white LEDs lasting for more than 5 min and the driving of an electric motor for running an electric fan for about 20 s upon charging a single SSC for 30 s in each case. The creation of active centers and defects on the porous microstructure of N, P-rGO also rendered the effective separation of biogenic neurotransmitters, dopamine and serotonin with an LOD of 20.0 and 10.0 nM, respectively.