A novel formaldehyde sensor containing AgPd alloy nanoparticles electrodeposited on an ionic liquid-chitosan composite film

► A HCHO sensor fabricated by electrodeposition of AgPd alloy is proposed. ► The HCHO sensor has high catalytic activity towards the electrooxidation of HCHO. ► The HCHO sensor has good tolerance to CO poisoning. ► The HCHO sensor has a low overpotential for the oxidation of formaldehyde.