Construction of 2D‐ZnS@ZnO Z‐Scheme Heterostructured Nanosheets with a Highly Ordered ZnO Core and Disordered ZnS Shell for Enhancing Photocatalytic Hydrogen Evolution

Abstract

Heterostructure and defects in photocatalyst play highly important role in photocatalysis. Formation of 2D‐ZnS@ZnO Z‐scheme heterostructure and introduction of zinc interstitial defects into ZnO were successfully achieved through a facile in‐situ ion‐exchange hydrothermal approach, and the photocatalysts exhibited high photocatalytic activity for hydrogen evolution. The heterointerface between the highly ordered ZnO core and disordered ZnS shell, and the zinc interstitial, facilitate the transfer and separation of charge carriers, resulting in high photocatalytic activity. The 2D‐ZnS@ZnO photocatalyst with a disordered ZnS layer of about 8 nm in thickness exhibited a photocurrent density about 7.2 times than that of ZnO, which is mainly attributed to the facilitative effect on interface transfer and the increased charge density. In addition, the photocatalytic activity can be adjusted via changing the thickness of the disordered ZnS overlayer. This work provides a strategy for the design of the heterointerface photocatalysts combined with defect engineering, through which the photocatalytic activity can be remarkably improved.

ZnO/ZnS-Polyvinyl Alcohol Hydrogel for Photocatalytic H2-Generation

“…Reaction mechanisms of H 2 evolution from scavenger Na 2 S/Na 2 SO 3 solutions containing S 2− , SO 3 2−, or S 2 O 3 2− with PVA-ZnOS hydrogel are proposed in Figure 7. The valence band maximum (VBM) and conduction band minimum (CBM) of ZnO and ZnS were widely reported in the literature [7][8][9][10][11][12][13][14], where the VB of ZnO is lower than that of ZnS and the CB of ZnS is higher than that of ZnO, allowing maximum redox capability of the ZnO/ZnS interface. The presence of Na 2 S/Na 2 SO 3 solution stimulates the H 2 evolution by scavenging photogenerated holes, suppressing the formation of S 2 2− from Na 2 S by SO 3 2− from Na 2 SO 3 [31].…”

“…The presence of Na 2 S/Na 2 SO 3 solution stimulates the H 2 evolution by scavenging photogenerated holes, suppressing the formation of S 2 2− from Na 2 S by SO 3 2− from Na 2 SO 3 [31]. When UV light was radiated, ZnO/ZnS photocatalyst was activated by Z-scheme heterojunction, where excited electrons at the CB of ZnO recombined with holes at the VB of ZnS [8,11,14]. The accumulation of holes at the VB of ZnO and electrons at the CB of ZnS reduced the recombination between electrons and holes, enhancing the photocatalytic reaction [13,14].…”

“…In addition, ZnS and ZnO are low-cost materials, of which synthesis methods of creating a heterojunction have been well studied. ZnS-ZnO photocatalyst can oxidize water to produce oxygen gas and simultaneously reduce water to form hydrogen gas [11,12]. We successfully developed ZnS-ZnO nanostructures for high-performance H 2 -generation reaction and Cr(VI) reduction [13,14].…”

3D Hydrangea‐like InVO4/Ti3C2Tx Hierarchical Heterosystem Collaborating with 2D/2D Interface Interaction for Enhanced Photocatalytic CO2 Reduction

“…To date, many semiconductor materials including TiO 2 , Bi 2 WO 6 , CeO 2 , ZnO, etc. have been widely investigated as photocatalysts for CO 2 photoconversion [2–5] . Though great progress has been achieved, there are still several issues to be overcome urgently.…”

Oxygen Vacancies Induced Plasmonic Effect for Realizing Broad‐Spectrum‐Driven Photocatalytic H2 Evolution over an S‐Scheme CdS/W18O49 Heterojunction

“…In the past decades, scientists have been committed to exploring renewable energy sources due to the increasing demand for fossil fuels and worsening environmental conditions [1–5] . As we know, H 2 energy, one of the cleanest energy sources, has been widely considered as a promising candidate to fossil fuel for solving the problem of energy crisis [6–10] . Since Fujishima and his colleagues first reported that TiO 2 electrode achieved photoelectrochemical water splitting in 1972, the photocatalytic H 2 production based on semiconductor photocatalysts has been taken for a prospective method to convert solar energy to chemical fuels [11–13] .…”