The as-prepared enzyme-like nitrogen-doped carbon dots were characterized by investigating their FL behavior. In this regard, the FL spectrum of the as-prepared CDs was recorded upon an excitation wavelength of 350 nm. The results are shown in Figure . As can be seen from this figure, the as-prepared CDs have an FL spectrum over 360-550 nm with a λmax at 404 nm, revealing successful synthesis of the enzyme-like nitrogendoped carbon dots.