Electrospun carbon nanofibers reinforced 3D porous carbon polyhedra network derived from metal-organic frameworks for capacitive deionization

Abstract

Carbon nanofibers reinforced 3D porous carbon polyhedra network (e-CNF-PCP) was prepared through electrospinning and subsequent thermal treatment. The morphology, structure and electrochemical performance of the e-CNF-PCP were characterized using scanning electron microscopy, Raman spectra, nitrogen adsorption-desorption, cyclic voltammetry and electrochemical impedance spectroscopy, and their electrosorption performance in NaCl solution was studied. The results show that the e-CNF-PCP exhibits a high electrosorption capacity of 16.98 mg g(-1) at 1.2 V in 500 mg l(-1) NaCl solution, which shows great improvement compared with those of electrospun carbon nanofibers and porous carbon polyhedra. The e-CNF-PCP should be a very promising candidate as electrode material for CDI applications.

Figure 1

(a–c) FESEM images of e-CNF-PCP at different magnifications and elemental mapping images of (d) e-CNF-PCP, (e) C element, (f) N element and (g) O element.

Figure 2

Raman spectra of (a) e-CNFs, (b) PCP and (c) e-CNF-PCP.

Figure 3

(a) Nitrogen adsorption-desorption isotherms and (b) pore size distribution of e-CNFs, PCP and e-CNF-PCP.

Figure 4

(a) CV curves and (b) Nyquist plots of e-CNFs, PCP and e-CNF-PCP in 1 M NaCl solution.

Figure 5

(a) EC transient, (b) current transient and (c) charge efficiency for e-CNFs, PCP and e-CNF-PCP electrodes at different applied potentials.

Figure 6

Linear fitting of the electrosorption of NaCl by e-CNFs, PCP and e-CNF-PCP electrodes using (a) pseudo-first-order kinetic equation and (b) pseudo-second-order kinetic equation.

Figure 7. ECs and charge efficiencies of e-CNFs, PCP and e-CNF-PCP in NaCl solutions with different initial concentrations.