RH and 75% RH, the RE of formaldehyde calculated by Equation ( ) is plotted in . It is worth mentioning that the RE of HCHO of Fe-N-C (85%) is higher than FeCo@NC (72.7%), suggesting that Fe-N-C is even more efficient than other SACs on catalytic oxidation of formaldehyde. It can be clearly seen from Figure that the RE of formaldehyde is essentially same at 0% RH and 75% RH when temperature is below 70°C, indicating that moisture has no effect on the conversion of catalyst at room temperature. However, at temperatures above 90°C, the RE of catalyst will be higher at 75% RH than at 0% RH, illustrating that the presence of moisture at high temperatures promotes the oxidation of