Synthesis of Co/Ni @ Al2O3-GO as novel oxygen reduction electrocatalyst for sustainable bioelectricity production in single-chambered microbial fuel cells

In this work, the synthesis of cobalt (Co) -nickel (Ni) nanoparticles supported on the matrix of alumina-graphene oxide (Al2O3-GO) and studies of their oxygen reduction reaction (ORR) activity in single-chambered microbial fuel cells (MFCs) were reported. A study of different weight ratios of Co-Ni nanoparticles with support material is accomplished to determine the catalyst performance. It is revealed that the catalyst Co-Ni (2:1)/Al2O3-GO (catalyst S-2) with a weight ratio of 2:1 of nanoparticles shows optimized properties among other electrocatalysts. The ORR study of hybrid catalysts suggested that the catalyst S-2 (reduction potential at 542 mV with -0.252 mA current) showed higher stability and electrocatalytic activities compared to catalyst Pt/C (reduction potential at 466 mV with -0.210 mA current) towards ORR. Al2O3-GO supported Co-Ni (2:1) catalyst revealed an improved ORR rate in single-chambered MFCs with a maximum power density of similar to 168 mW/m(2) compared to 102 mW/m(2) for Pt/C. The enhanced electrocatalytic activity of catalyst S-2 was accredited to the high electronic conductivity and longer stability of the nanocomposite. MFCB (catalyst S-2) showed the highest OCV values (668 +/- 15 mV), corresponding to the maximum electrochemical activity. Higher OCV values signified a stable biofilm developed on anode surface resulting in high electron transfer from microbes to anode surface, leading to maximum power production by catalyst S-2 in MFCB. The experimental consequences confirmed the employments of Al2O3-GO as a beneficial support matrix in constructing inexpensive and efficient cathode catalysts over standard Pt/C catalysts for single-chambered MFCs.

Automated summary

The study focused on the synthesis and performance evaluation of Co-Ni nanoparticles supported on Al2O3-GO matrix for oxygen reduction reaction in single-chambered microbial fuel cells. The hybrid catalyst Co-Ni (2:1)/Al2O3-GO showed higher stability and electrocatalytic activities compared to Pt/C catalyst, resulting in improved ORR rate and power density in MFCs. The enhanced electrocatalytic activity was attributed to the high electronic conductivity and long stability of the nanocomposite, making it a promising alternative to traditional Pt/C catalysts for MFC applications.