Type-II Band Alignment Enhances Unassisted Photoelectrochemical Water-Splitting Performance of the BaTiO₃/CdS Ferroelectric Heterostructure Photoanode under Solar Light Irradiation

Abstract

Here, we first use CdS nanoparticles to sensitize ferroelectric BaTiO3 nanostructures to construct the BaTiO3/CdS heterostructure photoanodes by a facile hydrothermal method and subsequent successive ionic layer adsorption and reaction. Combining the measurements of the valence band and core-level X-ray photoelectron spectroscopy spectra with energy band calculation, the type-II energy structure established at the BaTiO3 and CdS interface is confirmed. Benefiting from the type-II band alignment of the heterostructures, the spontaneous polarization electric field induced by BaTiO3, and the remarkable visible light absorption ability of CdS, the as-prepared BaTiO3/CdS heterostructure photoanode exhibits significantly improved and stable photoelectrochemical water-splitting activity. The highest photocurrent density of the constructed BaTiO3/CdS heterostructure photoanode with optimized CdS nanoparticle loading reaches up to 0.5 mA cm–2 at 0 V versus Ag/AgCl, which is about 12-fold that of the pure BaTiO3 photoanode. Additionally, the solar-to-hydrogen conversion efficiency of the BaTiO3/CdS heterostructure photoanode is 0.48% at 0.13 V versus reversible hydrogen electrode, 24-fold that of the bare BaTiO3 photoanode. In contrast with the photoelectrochemical performance of the other reported BaTiO3-based heterostructure photoanodes, the photocurrent density (0 V versus Ag/AgCl) and the solar-to-hydrogen conversion efficiency (0.13 V versus reversible hydrogen electrode) achieved by the present BaTiO3/CdS photoanode are the highest.

Synthesis and improved photoelectrochemical performances of oxygen-deficient TiO2/black-BaTiO3/CdS multiple-heterojunction nanoarrays

“…When the deposition times for the CdS layer were above 5, the photocurrent density of the composite film began to decline, suggesting that excessive deposition of CdS NPs was not conducive to the separation and transfer of the photogenerated carriers as demonstrated previously. 51,52 A similar trend can be observed in pure CdS photoelectrode, where the highest photocurrent density was obtained at 5 deposition times (see Fig. 6a).…”

Turning UV Light-Active BiOF into Visible Light-Active BiOF by Forming a Heterojunction with g-C3N4 and Its Photoelectrochemical Water Splitting Performance in Reverse Osmosis-Rejected Wastewater

“…The above-mentioned g-C 3 N 4 and BiOF-based heterojunction results obviously portray the type-II heterojunction charge-transfer mechanism with CB and VB alignment. Therefore, the g-C 3 N 4 /BiOF heterojunction interface electrode material probably possesses the type-II mechanism of PEC water splitting ,− (Figure ).…”

Recent Advances in Ferroelectric Materials-Based Photoelectrochemical Reaction

“…In addition to oxide semiconductors, metal sulfide semiconductor, such as CdS [ 50 , 51 , 52 ], Ag 2 S [ 53 ] etc., could enhance the photo-electric conversion by integrating with ferroelectric. Liu et al, reported that BaTiO 3 -CdS hybrid photocatalysts obtained H 2 production rate of 483 µmol∙h −1 ∙g −1 with the 20 wt% CdS loading due to the spontaneous polarization electric field of BaTiO 3 [ 52 ].…”