Highly Porous Carbon from Microalga, Chlorella Vulgaris, as an Electrochemical Hydrogen Storage Material

Abstract

Chlorella Vulgaris, as a well-known green microalga is considered as a reliable biomass source with vast biotechnological potential to produce various high-performance products. In the present study, porous carbon with a specific surface area was produced via a hydrothermal technique. The investigated materials were characterized by Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), energy-dispersive X-ray (EDX), Brunauer–Emmett–Teller (BET) and transmission electron microscopy (TEM). The electrochemical hydrogen storage (EHS) capacity of the product was investigated by a three-electrode system (chronopotentiometry) in 6 M KOH electrolyte. The microalga-based porous carbons showed a good electrochemical hydrogen storage capacity equal to 1040 mAh g−1 (≈3.9 wt%) after 40 cycles. This great capacity principally is due to the porous structure (distributions of pore size is mesoporous), high surface area (718 m2 g−1), and proper surface functional groups (C−OH, C–O–S and COO−) of prepared microalga-based porous carbons. These results suggested that the microalgal biomass could be successfully applied in electrochemical storage of hydrogen.