▎ 摘　　要

Facile synthesis of platinum nanocrystal and its improvement in catalytic activity still face great challenges. The paper reports one strategy for synthesis of platinum nanoparticle-serine-functionalized and boron-doped gra-phene quantum dot composite (Pt-Ser-B-GQD). The Ser-B-GQD was prepared by pyrolysis of serine, boric acid and citric acid at 180 degrees C for 3 h and then reacted with chloroplatinic acid to form platiunm nanocrystal. The resultant Pt-Ser-B-GQD offers a nanocage-like structure composing of tiny graphene sheets connecting many ultrasmall platinum nanocrystals with an average particle size of 8.2 +/- 0.32 nm. The combination of Pt nano -crystal with Ser-B-GQD results in the formation of Schottky heterojunction at the interface. The unique structure achieves to an improved catalytic activity. Pt-Ser-B-GQD was further used as Schottky heterojunction electro-catalyst for the construction of electrochemical sensor for the detection of vanillin. Because of excellent elec-trochemical properties, the sensor based on Pt-Ser-B-GQD exhibits a high sensitivity for electrochemical detection of vanillin. Differential pulse voltammetric peak current will increase linearly with increasing vanillin concentration in the range of 1 x 10-9-1 x 10-4 M with the detection limit of 2.8 x 10- 10 \M (S/N = 3). The proposed analytical method provides advantage of sensitivity, selectivity and reproducibility and was success-fully applied in the detection of vanillin in baby milk powder.