High carriers transmission efficiency ZnS/SnS₂ heterojunction channel toward excellent photoelectrochemical activity

Abstract

ZnS has been found superiority in photoelectrochemistry for the fast response of photo-inducing and its high conductor band position (~0.8 eV) results in strong reduction ability for hydrogen production. However, the solar absorbance of ZnS is much low for the wide band gap (~3.2 eV) and the carriers' migration efficiency also need to be improved. Here, nano-ZnS were coupled with ultrathin SnS 2 nanosheets as heterojunction composites. This heterojunction composite demonstrated largely increase in specific surface area (from 4 to 12-25 m 2 /g), obvious improvement of UV-vis absorbance and narrower band gap. Furthermore, the carriers' migration efficiency of ZnS/SnS 2 heterojunction has been confirmed to be much higher by photocurrent response and electrochemical impedance spectroscopy. Due to the improvement in structure, compared with pristine ZnS, this ZnS/SnS 2 heterojunction exhibited vast enhancement in photoelectrochemical performance. The composite with best activity exhibited 12.8 times enhancement in photocurrent density. The conduction band and valence band of ZnS are both more negative than those of SnS 2 , the photo-induced electrons at the conduction band of ZnS will transfer into the conduction band of SnS 2 while the photoinduced holes at the valence band of SnS 2 will transfer into the valence band of ZnS. In this way, the photo-produced carriers will flow into different semiconductors and the carriers' migration efficiency is enhanced. The work improves a new structure to develop the heterojunction property for photoelectrochemical application. K E Y W O R D Sheterojunction, photoelectrochemistry, SnS 2 , ZnS

Step-scheme porous g-C3N4/Zn0.2Cd0.8S-DETA composites for efficient and stable photocatalytic H2 production

“…In recent years, solid solutions have been extensively studied because of their excellent performances under visible light irradiation [38][39][40]. Zinc sulfide (ZnS) exhibits good photocatalytic activity and stability owing to its high conduction band energy position [41,42]. However, ZnS has a wide band gap (of about 3.5 eV) and can only be excited with ultraviolet light.…”

Constructing 1D/2D heterojunction photocatalyst from FeSe 2 nanorods and MoSe 2 nanoplates with high photocatalytic and photoelectrochemical performance

“…21 EIS curves of MS, FS, and MFS3 were shown as Figure 11; MS has the highest internal resistance, while that of FS is much lower. In the EIS curve, smaller curve radius means smaller internal resistance.…”

“…In the EIS curve, smaller curve radius means smaller internal resistance. 21 EIS curves of MS, FS, and MFS3 were shown as Figure 11; MS has the highest internal resistance, while that of FS is much lower. The internal resistance of MFS3 is smallest and significantly improved compared with MS, indicating that FS compositing can promote carrier transfer and reduce the internal resistance of materials.…”

“…The combustion product is water and free of pollution. [16][17][18][19][20][21][22][23][24][25][26][27][28] Compared with metal sulfides, metallic selenides have narrower bandgap and higher carrier mobility, but they are rarely studied. 1 In the process of photoelectrochemical hydrogen production, the most important is the choice of photocatalysts.…”

“…15 Among them, metal sulfides such as SnS 2 , MoS 2 , MnS, In 2 S 3 , and ZnS have narrow bandgap and high carrier mobility, and their photoelectrochemical properties are obviously better than those of metal oxides. [16][17][18][19][20][21][22][23][24][25][26][27][28] Compared with metal sulfides, metallic selenides have narrower bandgap and higher carrier mobility, but they are rarely studied. MoSe 2 is a two-dimensional material with a bandgap of only 1.7 eV, capable of absorbing sunlight at all UV-visible wavelengths.…”