Evaluation of templated N/P co-doped hierarchical mesoporous biocarbon/ 2D-molybdenum disulfide/polypyrrole composite as a supercapacitor electrode for U(VI) electrosorption

In this work, efficient and selective carbonaceous electrode materials based on hierarchical mesoporous functionalized carbon nanotubes, 2D-MoS2 nanosheets electrodeposited with variable content of polypyrrole (PPy) were prepared. The simple etching reaction between HNO3 and carbon nanotubes did not only modify the surface but also improved its hydrophilicity. The annealing of carbon nanotubes and electrodeposition of PPy increased the mesopore volume to total volume ratio (V-meso/V-t) from 0.42 to 0.86. The composite materials were characterized wisely using different characterization techniques and employed for efficient U6+ electro-assisted sorption through capacitive deionization. Electrode material with PPy content (0.3 M) exhibited good specific capacitance C-sp (100.2 F/g), improved V-meso (0.61 cm(3)/g), superb V-meso/V-t ratio (0.86) and large specific surface area S-BET (149.7 m(2)/g). The stated electrode showed fast sorption kinetics (t(eq)=30 min), admirable selectivity and exhibited the experimental sorption capacity of 274.50 mg/g at - 0.90 V. Electrochemical impendence spectroscopic study revealed that the resulting material exhibited relatively small charge transfer resistance (1.19 Omega cm(2)), minute electrolytic resistance (0.91 Omega cm(2)) and large double layer constant phase element (0.0368 S s(n)/ cm(2)). These significant characteristics promoted U6+ ions diffusion inside the hierarchical porous electrode surface for better performance of electrosorption process. This new class of hierarchical mesoporous composite electrodes may be used as potential supercapacitor materials not only for removal of uranium but also for other potent desalination applications.