TiO2 Nanosheet Arrays with Layered SnS2 and CoOx Nanoparticles for Efficient Photoelectrochemical Water Splitting

Abstract

Converting solar energy into sustainable hydrogen fuel by photoelectrochemical (PEC) water splitting is a promising technology to solve increasingly serious global energy supply and environmental issues. However, the PEC performance based on TiO2 nanomaterials is hindered by the limited sunlight-harvesting ability and its high recombination rate of photogenerated charge carriers. In this work, layered SnS2 absorbers and CoOx nanoparticles decorated two-dimensional (2D) TiO2 nanosheet array photoelectrode have been rationally designed and successfully synthesized, which remarkably enhanced the PEC performance for water splitting. As the result, photoconversion efficiency of TiO2/SnS2/CoOx and TiO2/SnS2 hybrid photoanodes increases by 3.6 and 2.0 times under simulated sunlight illumination, compared with the bare TiO2 nanosheet arrays photoanode. Furthermore, the TiO2/SnS2/CoOx photoanode also presented higher PEC stability owing to CoOx catalyst served as efficient water oxidation catalyst as well as an effective protectant for preventing absorber photocorrosion.

Recent research progress on operational stability of metal oxide/sulfide photoanodes in photoelectrochemical cells

“…As a binary metal sulfide, the stability of a SnS2 device is often affected by the self-oxidation of photogenerated holes and itself. Consequently, in addition to the above regulation of device stability through electrolyte regulation, including loading OECs or doping, the accumulation of photogenerated holes on the surface can be reduced as much as possible [178,179]. This starting point is basically consistent with the idea of improving the stability of CdS and other materials.…”

Novel Self-Powered Photodetector with Binary Photoswitching Based on SnSx/TiO2 Heterojunctions

“…The Nyquist plots are composed of a semicircle in the midhigh frequency region and a straight line in the low-frequency region. The electrochemical process is mix-controlled by charge transfer and the diffusion process. − All R s values are similar. R ct is the interfacial charge transfer resistance between SnS x and TiO 2 , which is 9.80 × 10 4 , 1.18 × 10 5 , and 9.38 × 10 4 Ω for the heterojunctions with SnS x nanoflakes grown for 30, 45, and 60 min, respectively.…”

Vertically oriented SnS2 on MoS2 nanosheets for high-photoresponsivity and fast-response self-powered photoelectrochemical photodetectors

“…These results suggest HV-SnS 2 /MoS 2 has a superior response speed compared with BP 2 , Te@Bi, 44 SnS, 49 BP/MoS 2 , 45 SnS 2 (FET), 54 and SnS 2 /MoS 2 (FET) 52 based photodetectors. Meanwhile, compared with voltage-driven photodetectors based on MoS 2 and SnS 2 heterostructures, 34,48,[50][51][52][53]55,56 the HV-SnS 2 /MoS 2 self-powered photodetector shows a fast response time but relatively lower photocurrent density and responsivity. To improve the photodetection capability of HV-SnS 2 /MoS 2 , applying an external bias may be an efficient way to accelerate the charge transport process.…”