Activated carbon (AC) is an inexpensive and sustainable catalyst for oxygen reduction in air-cathodes of microbial fuel cells (MFCs), but its electrical conductivity is relatively poor. To improve cathode performance, five different more conductive materials were added to AC: three carbon materials (carbon black, mesoporous carbon, and carbon nanotubes), and two metal powders (inexpensive copper and inert gold). Carbon-based particles improved maximum power densities by 6–14% compared to plain AC due to reduced charge transfer resistance. Copper powder had reduced performance, likely due to toxicity effects on the anode bacteria, while gold particles were similar to plain AC. Heat treated AC mixed with carbon black produced the highest power density of 1900 ± 76 mW m⁻², 41% higher than the widely used Pt air-cathode (1350 ± 55 mW m⁻²). The use of inexpensive carbon black with heat treatment was therefore the most effective and economical approach for improving cathode performance in MFCs.

中文翻译：

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添加导电颗粒以改善微生物燃料电池中活性炭空气阴极的性能

活性炭（AC）是一种廉价且可持续的催化剂，用于减少微生物燃料电池（MFC）的阴极中的氧气，但其电导率相对较差。为了提高阴极性能，向交流电中添加了五种不同的导电性更高的材料：三种碳材料（炭黑，中孔碳和碳纳米管）和两种金属粉末（廉价的铜和惰性金）。碳基颗粒由于降低了电荷转移阻力，因此与普通交流电相比，最大功率密度提高了6–14％。铜粉的性能下降，可能是由于对阳极细菌的毒性作用所致，而金颗粒与普通AC相似。热处理的AC与炭黑混合后产生的最高功率密度为1900±76 mW m ^-2，比广泛使用的Pt空气阴极（1350±55 mW m ^-2）高41％。因此，在热处理中使用廉价的炭黑是改善MFC中阴极性能的最有效，最经济的方法。