Preparation of high-crystalline 2D SnSe2/FTO photoanode and study on photoelectrochemical performance enhancement mechanism

Recently, two-dimensional (2D) layered materials have drawn great attentions in modern semiconductor industry due to the electronic and optoelectronic performances. SnSe2, as narrow bandgap and non-toxic semi-conductor, has become one of the great valuable materials due to its high electron mobility and unique layered structures. Herein, high-crystalline and high-purity 2D SnSe2/FTO photoanode was prepared by Chemical Vapor Deposition through controlling distances (d) and carrier gas flow rates (f) parameters, and first applied in photoelectrochemical simultaneous degradation RhB and Cr (VI) mixed solution. When d = 10 cm and f = 50 sccm, the highest photocurrent densities of 2D SnSe2/FTO photoanode are about 0.32 (full spectrum) and 0.24 (lambda >= 420 nm) mA cm(-2) at 1.23 V (vs. RHE), respectively. The maximum ABPE value of 2D SnSe2/FTO (d = 10 cm, f = 50 sccm) is 0.04% at 1.15 V (vs. RHE), which is 2.4 times than 2D SnSe2/FTO (d = 12 cm, f = 50 sccm). The simultaneous degradation efficiencies of the optimal photoanode are 35% and 28% for RhB and Cr (VI) in 60 min. The enhanced photoelectric performances of the optimal photoanode are mainly attributed to the wide spectral absorption range, the efficient separation and transmission of carriers and the fast chemical reaction at surface/interface. This work provides an abundant experimental basises for preparing the SnSe2-based heterojunctions, and opens a new direction for degrading the heavy metals and organic pollutants in wastewater environment.