Formation of Hexagonal PdSe2 for Electronics and Catalysis

Palladium diselenide (PdSe2), a novel but scarcely studied transition metal dichalcogenide (TMD), usually presents a pentagonal structure rather than a hexagonal one like other traditional TMDs. In this work, we successfully design and fabricate hexagonal PdSe2 that has only been predicted in theory. PdSe2 composed of an octahedral phase, which is one type of hexagonal phase, was prepared through a two-step method of selenizing the predeposited Pd. Interestingly, octahedral PdSe2 with great air stability presents intrinsic nanotubes. Moreover, fine structures including octahedral-pentagonal heterostructures are also detected in these nanotubes, which offer huge opportunities beyond traditional TMDs. The experimental band gap, valence band, and work function of the as-fabricated PdSe2 nanotubes are 0.7, 4.45, and 5.586 eV, respectively. Finally, a preliminary exploration of hexagonal PdSe2 nanotubes related to the selector device and photoelectrochemical water splitting indicates their potential for further applications in electronics and catalysis.