Efficient Photocatalytic Hydrogen Evolution via Band Alignment Tailoring: Controllable Transition from Type‐I to Type‐II

Abstract

Considering the sizable band gap and wide spectrum response of tin disulfide (SnS ), ultrathin SnS nanosheets are utilized as solar-driven photocatalyst for water splitting. Designing a heterostructure based on SnS is believed to boost their catalytic performance. Unfortunately, it has been quite challenging to explore a material with suitable band alignment using SnS nanomaterials for photocatalytic hydrogen generation. Herein, a new strategy is used to systematically tailor the band alignment in SnS based heterostructure to realize efficient H production under sunlight. A Type-I to Type-II band alignment transition is demonstrated via introducing an interlayer of Ce S , a potential photocatalyst for H evolution, between SnS and CeO . Subsequently, this heterostructure demonstrates tunability in light absorption, charge transfer kinetics, and material stability. The optimized heterostructure (SnS -Ce S -CeO ) exhibits an incredibly strong light absorption ranging from deep UV to infrared light. Significantly, it also shows superior hydrogen generation with the rate of 240 µmol g h under the illumination of simulated sunlight with a very good stability.

Remarkable Improvement in Photocatalytic Performance for Tannery Wastewater Processing via SnS2 Modified with N‐Doped Carbon Quantum Dots: Synthesis, Characterization, and 4‐Nitrophenol‐Aided Cr(VI) Photoreduction

“…Tin disulfide (SnS 2 ) is a promising photocatalyst owing to its low toxicity, economic cost, and wide spectral response, favoring the concept of green chemistry . However, limited by separating and transferring of photogenerated charges, SnS 2 possesses a low photocatalytic efficiency . Although loading noble metals as cocatalysts is an effective way to improve electron–hole separation, corresponding cost is highly increased .…”

Tailoring the Porosity in Iron Phosphosulfide Nanosheets to Improve the Performance of Photocatalytic Hydrogen Evolution

“…This absorption enhancement also underpinned better solar energy conversion efficiencies in other mesoporous or porous photocatalysts by maximizing light adsorption . According to the Kubelka–Munk theory, the bandgap energy of two catalysts can be estimated by transforming the UV/Vis DRS absorption spectra into a Tauc plot, in which the x and y axes correspond to and h μ and ( α h μ ) 1/2 , respectively . From the intercept of the tangent to h μ (Figure b), the bandgap values of smooth and porous FePS 3 nanosheets were estimated to be 1.97 and 2.04 eV, respectively, in a neutral environment .…”

SnS2 Nanosheets/H‐TiO2 Nanotube Arrays as a Type II Heterojunctioned Photoanode for Photoelectrochemical Water Splitting

“…Kelvin probe force microscopy measurements indicated that photogenerated electrons could be easily transported through the SnS 2 /H-TiO 2 interface but not through the SnS 2 /TiO 2 interface. [9] TiO 2 nanotubes (NTs) have attracted wide interesti nm any photocatalytic and photoelectrochemical reactions, for example, to facilitate carrier separation by the NTs. These findings show an effective route towards high-performance photoelectrodes for water splitting.…”

“…[3] Electron-hole pairs are difficult to effectively separatei nt ype Ih eterojunctions, in whicht he valence-and conduction-band edges of one moiety are embedded within those of the other moiety,b ecause both electrons and holes prefert oa ccumulate in the same moiety. [9] TiO 2 nanotubes (NTs) have attracted wide interesti nm any photocatalytic and photoelectrochemical reactions, for example, to facilitate carrier separation by the NTs. [4] Various type II heterostructures such as BiVO 4 /TiO 2 , [5] CdS/TiO 2 , [6] ZnS/ZnO, [7] or Fe 2 O 3 /Fe 2 TiO 5 , [8] have been designed to improve electron-hole separation efficiency.Normally,the type of band alignment between two materials is relatively set owing to their relativelyf ixed valenceand conduction-band positions if those two materials are chosen.…”

“…[2] Spatial separation of electron-hole pairs can be achieved in type II heterojunctions, in which the valence-and conduction-band edges in one moiety are offset from those in the other moiety,s ot he electrons and holes are separated into two independent moieties across the heterojunction, resulting in longer lifetime and lower recombination rate. [9] TiO 2 nanotubes (NTs) have attracted wide interesti nm any photocatalytic and photoelectrochemical reactions, for example, to facilitate carrier separation by the NTs. Therefore, it would be very attractive if the type of band alignment between two materials could be altered.…”