title: Molten-salt treatment of waste biomass for preparation of carbon with enhanced capacitive properties and electrocatalytic activity towards oxygen reduction.
abstract: Carbon powders are building blocks for electrochemical energy storage/conversion devices. Green, cost-affordable and facile preparation of carbon with applicable electrochemical properties is therefore essential for effective utilization of fluctuating renewable energy. Herein, the preparation of carbon nanoflakes via impregnation of waste biomass i.e. boiled coffee beans in molten Na2CO3-K2CO3 (with equal mass) at 800 °C and molten CaCl2 at 850 °C is reported. The microstructure and surface chemistry of the obtained carbons are specified. The correlations between synthetic conditions and microstructure/surface chemistry of the obtained carbons are rationalized. The derived carbon nanosheets are tested and compared as active materials for supercapacitors in a configuration of symmetric full cells in 1 M MeEt3NBF4 in acetonitrile and electrocatalysts towards the oxygen reduction reaction (ORR) in O2-saturated 0.1 M aqueous KOH. Despite the lower surface area, the carbon nanosheets derived in molten Na2CO3-K2CO3 exhibit enhanced capacitive properties and electrocatalytic ORR activity. The present study highlights the importance of thermal media on the microstructure, surface chemistry and electrochemistry of carbon from biomass.
authors.affiliation: School of Resource and Environmental Sciences, Hubei International Scientific and Technological Cooperation Base of Sustainable Resource and Energy, Wuhan University, Wuhan 430072, PR China. gabrielxiao@whu.edu.cn wangdh@whu.edu.cn.
authors.forename: Beihu
authors.initials: B
authors.lastname: Lu
authors.affiliation: School of Resource and Environmental Sciences, Hubei International Scientific and Technological Cooperation Base of Sustainable Resource and Energy, Wuhan University, Wuhan 430072, PR China. gabrielxiao@whu.edu.cn wangdh@whu.edu.cn.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhou
authors.affiliation: School of Resource and Environmental Sciences, Hubei International Scientific and Technological Cooperation Base of Sustainable Resource and Energy, Wuhan University, Wuhan 430072, PR China. gabrielxiao@whu.edu.cn wangdh@whu.edu.cn.
authors.forename: Yuqiao
authors.initials: Y
authors.lastname: Song
authors.affiliation: Advanced Energy Storage Materials and Devices Lab, School of Physics Electrical Information Engineering, Ningxia University, Yinchuan 750021, China.
authors.forename: Hailong
authors.initials: H
authors.lastname: Wang
authors.affiliation: School of Resource and Environmental Sciences, Hubei International Scientific and Technological Cooperation Base of Sustainable Resource and Energy, Wuhan University, Wuhan 430072, PR China. gabrielxiao@whu.edu.cn wangdh@whu.edu.cn.
authors.forename: Wei
authors.initials: W
authors.lastname: Xiao
authors.affiliation: School of Resource and Environmental Sciences, Hubei International Scientific and Technological Cooperation Base of Sustainable Resource and Energy, Wuhan University, Wuhan 430072, PR China. gabrielxiao@whu.edu.cn wangdh@whu.edu.cn.
authors.forename: Dihua
authors.initials: D
authors.lastname: Wang
mesh_terms: D018533:Biomass; D002244:Carbon / Q000737:chemistry*; D002254:Carbonates / Q000737:chemistry; D002384:Catalysis; D003069:Coffee / Q000737:chemistry; D004563:Electrochemistry; D055772:Green Chemistry Technology; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D011188:Potassium / Q000737:chemistry; D012037:Refuse Disposal / Q000379:methods*; D013499:Surface Properties; D014961:X-Ray Diffraction
chemical_list: D002254:Carbonates; D003069:Coffee; C005686:sodium carbonate; D002244:Carbon; C037593:potassium carbonate; D011188:Potassium; D010100:Oxygen