Porous carbon material prepared from Na2EDTA and its performance in capacitive deionization process.

Porous carbon materials were synthesized by a simple one-step pyrolysis of disodium ethylenediamine tetraacetate (Na 2 EDTA) under different temperature (650, 750 and 850 °C). Several characterization technologies were employed to evaluate the as-synthesized samples. Cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy tests were carried out to study the electrochemical property of the samples. The capacitive deionization (CDI) performance of the three samples-based electrodes was investigated and compared. The obtained results showed that pyrolysis temperature played a key role in the formation of the final products with different pore structure and heteroatom content, such as nitrogen and oxygen. Electrochemical performance measurement revealed that 750 °C sample exhibited the highest specific capacitance, the smallest diffusive resistance and charge-transfer resistance, and good conductivity. The salt electrosorption capacity of 750 °C samples were 8.02 mg g−1 at a low initial concentration of NaCl solution (25 mg L−1) and 27.75 mg g−1 at a high initial concentration of NaCl (500 mg L−1). The outstanding CDI performance of 750 °C material can be contributed to its high specific surface area and suitable pore structure. As a low-cost and processable precursor, Na 2 EDTA exhibited promising application prospect in large-scale CDI process. • Na 2 EDTA was employed as nitrogen- and oxygen-rich carbon precursors to fabricate porous carbon material (PC) through one-step pyrolysis process. • The existence of large amount of alkaline –COONa functional groups in Na 2 EDTA exhibited self-activated effect during the pyrolysis process, which simplified the fabrication of PC materials and avoided the usage of pore-forming agent. • The PC sample under 750 °C pyrolysis temperature showed the highest specific surface and pore volume and then a satisfying electrosorption capacity (8.02 and 27.75 mg g−1 with 25 and 500 mg L−1 initial concentration of NaCl solution, respectively). • Excessive high N content in PC sample may have contribution to the specific capacitance but did not do much to the increase of electrosorption capacity. [ABSTRACT FROM AUTHOR]