Abstract
The complexity of the chemical bonds in boron results in the polymorphism of borophene. To date, a variety of borophene polymorphs have been predicted. Because of its high chemical reactivity, boron reacts easily with other elements. Therefore, the most suitable method for the synthesis of borophene is molecular beam epitaxy, which is performed in an ultrahigh vacuum. In addition, some catalytic metal substrates can assist the growth process that leads to the experimental synthesis of borophene. In this chapter, we will review the synthesis processes of the different borophene polymorphs.