▎ 摘　　要

Boron doped polycrystalline diamond (BDD) films have shown great potential in electrochemical applications. However, the high background current and poor signal-to-noise ratio, caused by the crystal defects produced during the growth process, limit its application. This paper reports the controllable synthesis of a diamond/graphene/diamond (DGD) sandwich structure. The graphene interlayer is designed to act as a high-speed tunnel for the electronic transmission, and the outer diamond layers can completely maintain its inherent excellent features. This sandwich structure can effectively avoid the negative impact of surface non diamond carbon relative to material properties, and obtain a wider electrochemical window (3.65 V) and a lower background current (about 0.4 mu A cm(-2)). At the same time, this DGD electrode exhibits fast heterogeneous electron transfer in both the inner (Fe(CN)(6)(-3/-4)) and outer (Ru(NH3)(6)(+2/+3)) redox systems. By changing the preparation process of the middle G layer, the growth process of the G layer and its influence on the energy band and electrochemical performance of the electrode are analyzed in detail. In general, the DGD sandwich structure methodology paves a novel route for designing high-performance conductive diamond electrodes and holding great promise in electrochemical applications.