Promotional Effect of Cu₂S–ZnS Nanograins as a Shell Layer on ZnO Nanorod Arrays for Boosting Visible Light Photocatalytic H₂ Evolution

Abstract

The construction of systematically designed heterostructures with different integrated functionalities in a well-oriented nanoarchitecture is an efficient strategy for attaining high-performance photocatalysts. In this work, a heterostructural platform of ZnO–ZnS–Cu2S core–shell nanorod (NR) arrays is prepared as a photocatalyst for efficient H2 evolution using visible light. The fabrication is a three-step process involving solution growth of a ZnO NR array, followed by reactive sputtering of Cu2O, and then a sulfidation reaction. Addition of a ZnS interlayer to the ZnO–Cu2S core–shell arrays further extends the visible light absorbance range and promotes effective charge carrier separation. More importantly, the transition of Cu2O into Cu2S ensures the effective interaction of the core–shell assembly with the ZnS-based interface, thereby creating a valuable energy-level configuration and spectral bands that allow accurate separation of the photogenerated charge carrier. The effective H2 evolution in response to visible light irradiation is 436 μmol h–1 g–1 for the ZnO–ZnS–Cu2S (8 h) NR arrays, which is 2.55 and 1.61 times higher than that achieved with ZnO–Cu2O and ZnO–Cu2S photocatalytic NR arrays, respectively. The pollutant degradation rate for ZnO–ZnS–Cu2S (8 h) NR arrays under visible light irradiation is 7.8, 2.7, and 1.6 times higher than that achieved with pristine ZnO, ZnO–Cu2O, and ZnO–Cu2S core–shell structures, respectively. These visible light-responsive core–shell heterostructures show promising reuse properties and maintain their stability during use.

MOFs‐Derived Fusiform In2O3 Mesoporous Nanorods Anchored with Ultrafine CdZnS Nanoparticles for Boosting Visible‐Light Photocatalytic Hydrogen Evolution

“…Since the first report of solar‐driven H 2 generation over TiO 2 under UV‐light irradiation, a variety of semiconductor photocatalysts have been developed as photocatalysts for photocatalytic H 2 evolution from water. [ 16–29 ] Unfortunately, most semiconductors photocatalysts only have ultraviolet light responds, which accounts for only about 4% of solar radiation. Thus, one of the hotspots is to exploit high‐efficiency photocatalyst with visible‐light response.…”

Plasmon-induced ultrafast charge transfer in single-particulate Cu1.94S–ZnS nanoheterostructures

“…Copper sulfide (Cu 2-x S) is a p-type semiconductor with the Fermi level located near its VB, while zinc sulfide (ZnS) is an n-type semiconductor whose Fermi level lies close to its CB. 54,55 In Cu 1.94 S-ZnS NHs, the p-n heterojunction is formed along with the CE. Due to the existence of the internal electrostatic field in the p-n junction region, the equilibrium of Fermi energy in the NHs makes the CB of Cu 1.94 S locating above the CB of ZnS.…”

Design strategies of ZnO heterojunction arrays towards effective photovoltaic applications

“…Among them, using ZnO NRs array structure to construct the radial heterostructure can reduce the separation distance of carriers without sacrificing the light absorption of ZnO, so as to improve the transport efficiency of photogenerated carriers, which has become the first strategy to improve the photoelectric performance of ZnO‐based solar cells. For example, ZnS, 57–60 TiO 2 , 61,62 Cu 2 O, 63,64 and graphene 65–69 were combined with ZnO NRs to construct heterostructures and broaden the light absorption range of ZnO. With the aid of interface heterjunction materials of the two materials, it shows more obvious quantum effect and two‐dimensional characteristics.…”