Metal-free electrocatalysts for the oxygen reduction reaction (ORR) were synthesized from cassava residues through a thermal functionalization with sulfuric acid. Their electrocatalytic activities were tested through the ORR performance in basic media. Chemical composition in samples seems to play an important role in their electroactivity, more than textural properties, as the sulfur-treated high-temperature sample (Sy800) has the best performance with an onset potential of 0.69 V vs RHE (reversible hydrogen electrode) and a current of −2.32 mA cm⁻² at 0.3 V vs RHE. These functionalized cassava residues are promising materials to be used like carbon-based metal-free electrocatalysts.

木薯残渣通过硫酸热官能化合成了用于氧还原反应（ORR）的无金属电催化剂。通过在碱性介质中的ORR性能测试了它们的电催化活性。样品中的化学成分似乎在其电活性中起着重要作用，而不是质构性质，因为经硫处理的高温样品（Sy800）具有最佳性能，其起始电势相对于RHE（可逆氢电极）为0.69 V，而相对于RHE（可逆氢电极）和与RHE相比，在0.3 V下的电流为-2.32 mA cm ^-2。这些功能化的木薯残基是很有希望使用的材料，如无碳金属基电催化剂。