Elsevier

Solar Energy

Volume 227, October 2021, Pages 217-223
Solar Energy

Sustainable electricity generation from photo-bioelectrochemical cell based on carbon nanotubes and chlorophyll anode

https://doi.org/10.1016/j.solener.2021.09.002Get rights and content

Highlights

  • Chlorophyll from Chlorella could produce energy as an electrode of photo-bioelectrochemical cell.

  • We assembled a CNT/Chlorophyll hybrid anode.

  • The anode applied to photo-bioelectrochemical cells to form a green energy device.

  • The highest maximum output was 9.48 mW/m2.

Abstract

This study developed a photo-bioelectrochemical cell based on CNT-chlorophylls to produce photocurrent by lighting electrodes in water-based solutions. The extracted chlorophyll from Chlorella vulgaris microalgae was used to modify carbon nanotube (CNT) as a photo-biocatalyst offering low cost and abundant resources. Furthermore, it is an excellent choice as an alternative bioenergy feedstock compared to lignocellulosic material. The physical interactions between the hydrophobic chlorophyll tail and the hydrophobic nature of the CNT induce the hydrophobic interaction. Subsequently, the CNT/chlorophyll photo-biocatalyst ink was deposited on the carbon felt and used as a photo-anode in photo-bioelectrochemical cells. With the introduction of light, the CNT/chlorophyll photo-biocatalyst is capable of generating 6 times higher photo-currents than in the dark. Also, the maximum power density produced by this device was about 9.48 mW/m2, which is eleven times greater than the CNT control. Therefore, this analysis is a promising system of generating relatively large amounts of photo-bioelectrochemical current by incorporating biological renewable material of chlorophyll derived from Chlorella vulgaris.

Introduction

Green microalgae are commonly used in the production of fuel (biodiesel and bioethanol), hydrogen, and other value-added chemicals (chlorophyll, protein) (Dixon and Wilken, 2018, Shuba and Kifle, 2018, Ariede et al., 2017, Khetkorn et al., 2017). The relatively simple cellular organization of the algae has provided the advantage of its photosynthetic processes to generate metabolic products.

In recent years, the use of chlorophyll held by plants and microalgae has shown a growing interest in the imitation of natural photosynthetic energy transfer processes (Wang et al., 2018, Dau et al., 2017). This is a step towards replacing non-biological electrochemical catalysts, which are not sustainable and may affect the ecosystem (Guo et al., 2020, Shen et al., 2020, Fu et al., 2019). Several studies have developed the direct transformation of light into electrical energy by photosynthesis in electrical cells using natural systems such as thylakoids, chlorophyll, photosynthesis reaction centers, and all microalgae cells (Carpentier and Mimeault, 1987, Katz et al., 1990, Ptak et al., 1997, McCormick et al., 2011). The electrogenic properties of chlorophyll isolated from green microalgae are particularly worthy of exploration in photo-bioelectrochemical cells for direct power generation.

Chlorophyll direct energy processing as a photo-biocatalyst is preferable to other dyes due to its availability and efficiency in absorbing light. The processes in Photosystem I (PS-I) and II (PS-II) can directly turn light into energy (Duan et al., 2020, Liu et al., 2020). Chlorophyll is readily modified by other biological materials, which renders it an excellent candidate as a photo-biocatalyst (Frias et al., 2018). In addition, natural electrochemical cells provide some distinctive benefits such as (i) low costs and (ii) self-sufficient inorganic substances (Sekar et al., 2014).

Although it has many advantages due to its comparatively low transmission efficiency, the electrochemical cell technology which uses photo-biocatalyst dye is still inadequate for producing a full amount of power towards research implementation (Esper et al., 2006). For this cause, it is important to improve chlorophyll function by using supporting materials including carbon nanotubes (CNTs). CNTs have several advantages such as large specific surfaces, strong conductivity, and exceptional chemical stability as supporting material (Alim et al., 2018).

Few people use chlorophyll in conjunction with other chemicals to produce electricity, where dye synthesized solar cell (DSSC) is commonly used (Siddick et al., 2018, Wang et al., 2019, Mary Rosana et al., 2020, Zhang et al., 2020). To be applied as a biocatalyst anode for photo-bioelectrochemical cells, there are limited records of its alteration in CNTs.

In this study, the direct electron transfer (DET) capability of chlorophyll from Chlorella vulgaris as a photo-biocatalyst was investigated and modified using CNT as supportive material for the current generation of photo-bioelectrochemical cells. This is accomplished by adding chlorophyll to the surface wall of the CNT to form CNT/chlorophyll, which is used as an anode in the cells. This study is an intellectual novelty; hence, it is expected to enable potential research teams to grow green energy dependent on natural dyes.

Section snippets

Chlorophyll extraction

The extraction of Chlorella vulgaris microalgae chlorophyll was performed by using methods from previous studies (Sartory and Grobbelaar, 1984, Simon and Helliwell, 1998). A reflux procedure through a soxhlet system was carried out for two hours using methanol as the solvent for many g of commercial Chlorella powder at 60 °C. Subsequently, the chlorophyll solution was extracted and the same process was replicated by the fresh solvent three times. Quantification of the extracts by UV–Vis was

Morphology analysis

Scanning Electron Microscopy was used to investigate the interaction between MWCNT and chlorophyll, as shown in Fig. 2. Fig. 2a is a pure CNT without chlorophyll. Contrastingly, there were several noticeable changes on the surface morphology of CNT/chlorophyll photo-biocatalyst as shown in Fig. 2b compared to the pure CNT (Fig. 2a). Firstly, the chloroplast granules, that were the origin of chlorophyll, were noticeably attached to the surface of CNT although it was postulated that some of

Conclusions

In this study, a photo-bioelectrochemical cell that adopted an anode system based on CNT-chlorophylls was developed. The anode was designed by CNT through a chlorophyll coating technique, while the extracted chlorophyll was gotten from Chlorella vulgaris microalgae. The CNT/chlorophyll had bandgap energy of 2.72 eV, which was 5% higher than CNT. CV studies were carried out to establish the role of chlorophyll in electricity generation at all anode alteration stages and, in the presence, or

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgments

This research was supported in full with Toray Science & Technology Research Grant 2020 provided by Indonesia Toray Science Foundation.

References (41)

  • S.Z. Siddick et al.

    An investigation of the dye-sensitized solar cell performance using graphene-titania (TrGO) photoanode with conventional dye and natural green chlorophyll dye

    Mater. Sci. Semicond. Process.

    (2018)
  • D. Simon et al.

    Extraction and quantification of chlorophyll a from freshwater green algae

    Water Res.

    (1998)
  • M. Syamila et al.

    Effect of temperature, oxygen and light on the degradation of β-carotene, lutein and α-tocopherol in spray-dried spinach juice powder during storage

    Food Chem.

    (2019)
  • M.M. Tostado-Plascencia et al.

    Synthesis and characterization of multiwalled carbon nanotubes functionalized with chlorophyll-derivatives compounds extracted from Hibiscus tiliaceus

    Diam. Relat. Mater.

    (2018)
  • S. Wang et al.

    Chlorophyll-based organic solar cells with improved power conversion efficiency

    J. Energy Chem.

    (2019)
  • C. Zhang et al.

    A chlorophyll derivative-based bio-solar energy conversion and storage device

    Electrochim. Acta

    (2020)
  • M.E. Barbinta-Patrascu et al.

    Nanobioarchitectures based on chlorophyll photopigment, artificial lipid bilayers and carbon nanotubes

    Beilstein J. Nanotechnol.

    (2014)
  • J.O. Calkins et al.

    High photo-electrochemical activity of thylakoid–carbon nanotube composites for photosynthetic energy conversion

    Energy Environ. Sci.

    (2013)
  • G. Calogero et al.

    Natural dye senstizers for photoelectrochemical cells

    Energy Environ. Sci.

    (2009)
  • R. Carpentier et al.

    The photosynthetic partial reactions involved in photoelectrochemical current generation by thylakoid membranes

    Biotechnol. Lett.

    (1987)
  • Cited by (7)

    View all citing articles on Scopus
    View full text