The Synthesis Of Hierarchical Porous Carbon Electrode Materials And Their Applications In Capacitive Deionization And Electrocatalysis

The rapid development of global economy has brought the serious pollution of the environment,so that utilization of more water resources and sustainable clean energy,as well as efficient energy conversion and storage technology,become the urgent problem needed to solve.Capacitive deionization technique is a new type of water treatment technologies,and also used for the development of low cost and efficient electrocatalysts.This article mainly consists of two part works:1.With citric acid as carbon source,herein,we applied in situ foamed Mg chelates as precursors for the scalable fabrication of hierarchically porous carbon(HPC).Citric acid first reacted with magnesium nitrate to form Mg chelate while the generated gaseous HN03 molecules bubbled the intermediate carbon framework to produce abundant open pores.The precursors were then submitted to inert annealing with potassium hydroxide to obtain high-carbonization hierarchically porous(micropore,mesopore and macropore)carbon materials.Electrochemical measurements revealed that the optimized sample(HPC-2)exhibited a high specific capacitance of 236.5 F·g-1(1.0 A·g-1)and over 60.0%retention of capacitance at high working current density(10.0 A·g-1)in 1.0 mol L-1 NaCl solution.Furthermore,it showed impressive capacitive deionization performance regarding both desalination capacity(28.76 mg·g-1 in 45.0 mg L-1 NaCl solution)and cycling stability.It shows that NPCs are excellent electrode materials for supecapacitor and capacitive deionization.2.With EDTA as carbon source and nitrogen source,then submitted to inert annealing with potassium hydroxide after hand grinding,hierarchically porous N-doping carbon materials(NPC)with highperformance in supercapacitor and capacitive deionization were obtained.Then with NPC as electrode materials,utilizing capacitive deionization technology in CoCl2 solution developed a new type of electrocatalysts with high-performance in oxygen reduction reaction.In this work,we also discussed the influence of the CoCl2 concentration and calcination after capacitive deionization as well as calcination temperature on the property of the new type electrocatalyst.In addition,this article studied the the performance of the oxygen reduction reaction over the NPC electrocatalysts developed using other non-precious metals and carbon materials by capacitive deionization technology.