Chlorella-derived activated carbon (CDAC) with a high specific surface area and hierarchical pore structure was prepared as a CO2 adsorbent and as a supercapacitor electrode material. During KOH activation of Chlorella-derived carbon, metallic K gas penetrated from the outer walls to the inner cells, and pores formed on the outer frame and the inner surface. Micropores were dominant in CDAC, contributing toward a high specific surface area (> 3500 m2/g) and a hierarchical pore structure owing to the cell walls. Consequently, CDAC exhibited a high CO2 adsorption capacity (13.41 mmol/g at 10 atm and room temperature) and afforded high specific capacitance (142 F/g) and rate capability (retention ratio: 91.5%) in supercapacitors. Compared with woody- and herbaceous-biomass-derived activated carbons, CDAC has a superior specific surface area when the precursors are used without any pretreatment under the same conditions due to their soft components such as lipids and proteins. Furthermore, developing microalgae into high-value-added products is beneficial from both economic and environmental perspectives.

Chlorella-derived activated carbon with hierarchical pore structure for energy storage materials and adsorbents
    Abstract
    1 Introduction
    2 Experimental
        2.1 Preparation of CDAC
        2.2 Preparation of other biomass-derived activated carbon
        2.3 Physical characterization of CDAC
        2.4 Electrochemical characterization
        2.5 Determination of CO2 adsorption capacity
    3 Results and discussion
    4 Conclusions
    Acknowledgements 
    References

• Joah Han(Energy and Environmental Division, Korea Institute of Ceramic Engineering and Technology/Department of Materials Science and Engineering, Korea University)
• Kyubock Lee(Graduate School of Energy Science and Technology, Chungnam National University)
• Min Sung Choi(School of Chemical Engineering, Sungkyunkwan University)
• Ho Seok Park(School of Chemical Engineering, Sungkyunkwan University)
• Woong Kim(Department of Materials Science and Engineering, Korea University)
• Kwang Chul Roh(Energy and Environmental Division, Korea Institute of Ceramic Engineering and Technology)