Three-dimensional nanoporous SnO2/CdS heterojunction for high-performance photoelectrochemical water splitting

The porous structure is one of the effective structures to improve the photoelectrochemical (PEC) performance due to its high surface area to volume ratio. In this study, a porous carbon black (CB) film was prepared by a simple and inexpensive flame method, which was used as a template to grow three-dimensional (3D) nanoporous SnO2 through the atomic layer deposition (ALD) method, followed by CdS thin film coating. The photocurrent density of the optimized 3D nanoporous SnO2/CdS heterojunction (11.56 mA/cm(2), 1.23 V vs. RHE) shows 9.7 times higher than that of planar SnO2/CdS film (1.20 mA/cm(2), 1.23 V vs. RHE), meanwhile, the photocurrent stability was also 2.2 times improved. The maximum incident photon-to-current conversion efficiency (IPCE) and applied bias photo-to-current efficiency (ABPE) values of 35% (around 490 nm at 0 V vs. RHE) and 1.85% (at 0.90 V vs. RHE) were observed for the nanoporous SnO2/CdS. Furthermore, the surface charge separation and bulk charge transfer efficiencies have been achieved by 45.4% and 98.8% (1.23 V vs. RHE). As a whole, the results indicated that the 3D nanoporous SnO2/CdS heterojunction has been demonstrated as an efficient strategy that has been realized to show high performance in PEC water splitting.

Automated summary

The study focused on improving the photoelectrochemical (PEC) performance by preparing a porous carbon black (CB) film as a template to grow 3D nanoporous SnO2 through ALD method, followed by CdS thin film coating. The 3D nanoporous SnO2/CdS heterojunction showed significantly higher photocurrent density, IPCE, and ABPE values compared to planar SnO2/CdS film, demonstrating its efficiency in PEC water splitting.