▎ 摘　　要

To meet the rising demand of graphene in electronics and optoelectronics, developing an efficient synthesis strategy for effective control of the layer thickness is highly necessary. Herein, we report the synthesis of strictly single-layer graphene on the foil of an early transition metal, tungsten (W), via a simple chemical vapor deposition route. The cracking of hydrocarbons is facilitated by the catalytically active metal surface of W, while the subsequent two-dimensional growth is mediated by the carbide-forming ability within the underlying bulk, leading to the formation of uniform monolayer graphene. The as-grown graphene layers can be transferred onto target substrates rapidly through the recently developed electrochemical method, which also allows for reuse of the substrates at least five times without introducing quality deterioration. Moreover, considering the refractory nature of W foils, a complementary component of nickel is added, by means of which the growth temperature of graphene can be significantly reduced. In brief, a highly-efficient and low-cost synthesis route has been developed for the growth of graphene towards large-area uniformity, single-layer thickness and high crystalline quality.