Hurdles and recent developments for CdS and chalcogenide‐based electrode in “Solar electro catalytic” hydrogen generation: A review

Abstract

There are tremendous efforts to realize the idea of employing photoelectrochemical (PEC) technology for generating chemical energy from solar energy. The most important feature of this technology is to coordinate the energetics of an electrochemical reaction with the solar spectrum. So, the photoelectrochemistry of a semiconducting material plays a vital role in this arena. Exploring an efficient and stable semiconductor material for such purpose is an essential prospect. There are several sulfide selenide-based semiconductors viz. II-VI (Zn/Cd = S/Se) semiconductors those exhibit high potential in PEC application. Nonetheless, they suffer by certain corrosion issues, which are important to be reviewed and are discussed here. This review highlights the significant role of cadmium chalcogenides among various materials explored in this technology. CdS is the most studied system among all those with perfect band gap and band-edge position exhibiting material, desired for photoanode in PEC cell. Next, recent progresses achieving enhancement in the performance of CdS photoanodes by doping, modifying the surface, morphology reconstruction, and engraving heterostructure is discussed in detail. The role of the nanostructured techniques, improved photo electrochemistry with redox couples, and advanced interfacial and band gap engineering is explored to overcome the lack of chemical stability of CdS. The review concludes with the bright scope of CdS as an efficient PEC material in the form of combined semiconductor systems with an optimum band gap, bandedge, and their complimentary properties rather than a single component material.

Type‐II CdSe/ZnO Core/Shell Nanorods: Nanoheterostructures with A Tunable Dual Emission in Visible and Near‐Infrared Spectral Ranges

“…[ 23 ] Drawbacks of many of the prepared materials are the presence of toxic heavy metals in their structure and the limited photochemical stability of chalcogenides. [ 24 ] The development of structures combining chalcogenide NR cores with metal oxide shells could address some of these limitations and lead to introduction of new functionalities. For example, ZnSe/ZnO NRs [ 25 ] showed enhanced photocatalytic activity compared to the ZnSe cores.…”

Growth-control of hexagonal CdS-decorated ZnO nanorod arrays with low-temperature preheating treatment for improved properties and efficient photoelectrochemical applications

“…Fundamentally, CdS is considered to be more stable in polysulfide electrolyte and is less toxic if compared to CdSe and CdTe. 12 …”

“…Fundamentally, CdS is considered to be more stable in polysulde electrolyte and is less toxic if compared to CdSe and CdTe. 12 As reported in most literature, the fabrication of the cascaded ZnO/CdS heterojunction is possible via the implementation of a simple successive ionic layer absorption and reaction (SILAR) method. 7,8,11 Other than the advantageous charge transfer ability discussed above, the type-II heterostructure of ZnO/CdS is significant for inhibiting the photo-corrosion of CdS under light illumination, which is induced by the accumulation and oxidization of photogenerated holes.…”

Porous Zn1–xCdxSe/ZnO Nanorod Photoanode Fabricated from ZnO Building Blocks Grown on Zn Foil for Photoelectrochemical Solar Hydrogen Production

“…The production of hydrogen as a clean fuel using hybrid semiconductors is broadly studied as a potential way to reduce the environmental pollution triggered by fossil fuel combustion. , Photoelectrochemical (PEC) hydrogen generation through the direct conversion of solar energy into hydrogen energy has attracted great attention. , Recently, various types of one-dimensional (1D) metal oxide semiconductors (ZnO, BiVO 4 , TiO 2 , and WO 3 ) have been used for the utilization of hydrogen energy through the PEC method. − Among them, ZnO is a suitable metal oxide semiconductor candidate due to its superior stability and conductivity, but it has limits due to large bandgap and electron–hole recombination . Therefore, coupling of metal oxide with other narrow bandgap chalcogenide semiconductors (CdS, CdSe, and CdTe) could enhance charge generation, reduce the recombination rate, and improve the PEC hydrogen production performance. − Among them, CdSe has received the most attention in the past years due to its narrow bandgap (1.8 eV) and excellent PEC photocurrent density. , However, conventional metal chalcogenides are more difficult to manage in terms of geometrical size and shape than organic compounds . Consequently, a novel class of inorganic–organic hybrid materials formed by fusing an organic component with an inorganic building block has attracted considerable interest. , An innovative organic–inorganic hybrid material shows a significant quantum confinement effect with a precise periodic arrangement but suffers from poor PEC properties due to a wide bandgap .…”