Ternary Monolithic ZnS/CdS/rGO Photomembrane with Desirable Charge Separation/Transfer Routes for Effective Photocatalytic and Photoelectrochemical Hydrogen Generation

Abstract

Highly efficient and easy recyclable monolithic photocatalysts with ideal separation/transport route for photogenerated charge carriers are much desired. In this work, a ZnO seed‐induced growth approach is developed to fabricate a ternary monolithic photomembrane, that is, ZnS/CdS heterojunction nanorods in situ grow into the interspaces of multilayer reduced graphene oxide (rGO) sheets (denoted as ZnS/CdS/rGO). The monolithic ZnS/CdS/rGO photomembrane can serve as an efficient visible‐light photoactive membrane for photocatalytic (PC) or photoelectrochemical (PEC) hydrogen generation. The fast electron transport of 1D CdS nanorods, the excellent electronic conductivity of multilayer stacked rGO sheets, the intense visible‐light absorption of CdS, the unique hierarchical structure, and double heterojunctions (ZnS/CdS and CdS/rGO) efficiently boost the photogenerated electron‐hole pairs separation and transfer across the interfacial domain of the photomembrane under visible‐light irradiation. Furthermore, the superior stability and reusability of the photomembrane is achieved by the ideal process of photogenerated electron‐hole pair separation/transfer, i.e., holes transfer to ZnS and electrons transfer to rGO to inhibit CdS from photocorrosion.

Challenges and prospects about the graphene role in the design of photoelectrodes for sunlight-driven water splitting

“…A particular case where rGO is used as support for the growth of ZnS/Cd NRs open the possibility of designing new organized heterojunctions with attractive properties. 156 Additionally to the photocurrent improvement associated with graphene as charge transfer mediator, 158,160,169 the ZnS role as charge collector and the CdS absorption capability, the authors could not reproduce a similar pattern on the heterojunction without rGO addition.…”

“…nanowires, 153 NRs 154,155 and nanoflowers 154 ), introduction of noble metal nanoparticles ( e.g. Pt 156 and Au 157 ), formation of heterojunctions ( e.g. TiO 2 /CdS 158 and CdS/MoS 2 (ref.…”

Acceptorless Photocatalytic Dehydrogenation of Furfuryl Alcohol (FOL) to Furfural (FAL) and Furoic Acid (FA) over Ti3C2Tx/CdS under Visible Light

“…[38][39][40] Different cocatalysts, including metals nanoparticles, transition metal chalcogenides and molecular cocatalysts, which act as catalytic active sites for hydrogen evolution and to suppress the recombination of the photogenerated charge carriers, have been deposited on CdS to promote the photocatalytic activity for hydrogen evolution over CdS. [41][42][43][44][45][46][47] As a new type of two-dimensional (2D) transition metal carbide, Ti 3 C 2 T x MXene (T =À OH, À O and À F) was previously reported to be active for electrochemical hydrogen evolution. [48][49][50][51][52] The use of MXene as efficient cocatalyst for semiconductor-based photocatalytic hydrogen evolution have also been demonstrated.…”

“…2.4 eV) corresponding well to the visible light absorption, CdS has demonstrated promising activity for photocatalytic hydrogen evolution from water containing sacrificial reagents under visible light [38–40] . Different cocatalysts, including metals nanoparticles, transition metal chalcogenides and molecular cocatalysts, which act as catalytic active sites for hydrogen evolution and to suppress the recombination of the photo‐generated charge carriers, have been deposited on CdS to promote the photocatalytic activity for hydrogen evolution over CdS [41–47] . As a new type of two‐dimensional (2D) transition metal carbide, Ti 3 C 2 T x MXene (T=−OH, −O and −F) was previously reported to be active for electrochemical hydrogen evolution [48–52] .…”