Direct ethanol fuel cells (DEFCs) are considered as the ideal green power suppliers because of high energy density and non-toxicity of ethanol. Here the ball cactus-like gold (Au) particles reduced by hydrogen peroxide solution are coated with sulfhydryl-functionalized carbon dots (SCDs-Au). When the SCDs-Au composite is employed as the anodic electrocatalyst for ethanol oxidation reaction, an anode peak current density of 23.23 mA cm(-2)(mass activity of 102.65 mA mg(-1)) is obtained at 0.19 V (vs. SCE) in 1.0 M KOH and 1.0 M ethanol at a scan rate of 20 mV s(-1), which is about 4.4 times than that of Au without modification of SCDs. The higher catalytic activity is attributed to the higher ethanol adsorption capability caused by the shell-like SCDs. According to the adsorption experiment, ethanol adsorption capability of SCDs-Au is calculated as 2.8 times than that of Au without modification. At the same time, the addition of SCDs improves the electrocatalytic stability of Au. Such a surface modification method can be applied in other catalyst design processes. [GRAPHICS] .