English abstract
Microbial Desalination Cell (MDC) is a promising bio-electrochemical system (BES)
for desalination while treating wastewater with minimal energy consumption.
However, the poor performance due to cathodic limitation hinders their large-scale
application. The cathodic reduction reaction is an electrochemical surface
phenomenon; thereby, the cathode's surface charge transfer and thermodynamic
efficiency are crucial for reaction kinetics. To improve the cathodic reaction kinetics,
the study investigated on Bismuth oxychloride (BiOCl), which is an earth-abundant,
nontoxic, anti-corrosive light-responsive electro-catalyst hybridized with a very
promising graphitic-C3N4 (GCN), a graphene-like electronic structured catalyst coated
on stainless steel mesh (SSM) support for MDC cathode. Several photo electrocatalysts of BiOCl/GCN were prepared from different compositions of BiOCl
to GCN. All the combinations of the prepared photo-electrocatalysts were
characterized to understand surface morphology via FTIR, XRD, and Photo
luminance-spectroscopy (PL-spectra) and for electrochemical activity via cyclic
voltammetry (CV). FTIR and XRD spectroscopies confirm the successful synthesis of
the BiOCl/GCN composites by adhering to distinct properties of BiOCl and GCN. PL spectra analysis revealed the effectiveness of BiOCl/GCN composites in reducing the
recombination effect of photocarriers in comparison to the blank BiOCl and GCN. To
understand the electrochemical performance of BiOCl/GCN composites with/without
activated carbon, CV analyses with different loading rates (i.e., 20, 30, and 50 mg/cm2
)
were performed in the presence/absence of light. The 40 mg/cm2
loaded and AC
supported heterojunctions exhibited higher redox current densities, revealing the
effectiveness of AC as conductive support material. BiOCl/GCN (100:0 wt.%),
BiOCl/GCN (75:25 wt.%) & BiOCl/GCN (25:75 wt.%) were the best three performing
hybrids. However, the catalysts performed similarly in the absence and presence of
light. These results contrast with the morphological analysis that confirmed the
photocatalytic structure of BiOCl/GCN. These findings may be attributed to the type
of light source, which demands further characterization studies. The research will
eventually aid in understanding the potential applications of such promising
composites for advanced electrochemical applications, including renewable energy
recovery, electrochemical desalination, photovoltaic energy, and much more.
