Construction of Z-Scheme System for Enhanced Photocatalytic H₂ Evolution Based on CdS Quantum Dots/CeO₂ Nanorods Heterojunction

Abstract

Photocatalytic hydrogen evolution from water splitting is a promising approach in energy conversion and storage. Here, the 0D/1D CdS quantum dots (QDs)/CeO2 nanorods heterojunction was designed and fabricated by a facile two-step method. The optimum photocatalytic H2 evolution activity for CeO2-based composites with 3 at. % CdS QDs (101.12 μ mol h–1 g–1) was 45 times as high as that of pure CeO2 nanorods (2.25 μ mol h–1 g–1) under light irradiation. Meanwhile, the photocurrent response intensity increased 17.75 times higher than pure CeO2 nanorods. Furthermore, the 0D/1D CdS QDs/CeO2 heterojunctions exhibited enhanced photocatalytic stability for long lifetime (60 h). The reasons that dramatically enhanced photocatalytic performance could be the improved light harvesting, enhanced photoresponse and stronger electronic conductivity while the CdS QDs was loaded in CeO2 nanorods to form the 0D/1D heterojunctions CdS QDs/CeO2 nanocomposites. What’s more, the remarkably increased photocatalytic performance of CdS QDs/CeO2 composites was mainly attributed to the Z-scheme between CdS QDs and CeO2 nanorods, which was confirmed by the PL (photoluminescence) method. Therefore, the proposed system is highly promising for large scale photocatalytic hydrogen evolution.

Ni-based photocatalytic H2-production cocatalysts2

“…In another example, Peng et al [350]. Furthermore, CdS QDs have been employed to sensitize various semiconductors with wide bandgaps, such as TiO2 and g-C3N4, for enhanced photocatalytic H2 evolution [366][367][368][369][370]. Wang et al [315] fabricated CdS QD-sensitized TiO2 hybrid photocatalysts with dual Ni(OH)2 and CNT cocatalysts that were anchored on the TiO2 surface for photocatalytic H2 generation.…”

Inside‐and‐Out Semiconductor Engineering for CO2 Photoreduction: From Recent Advances to New Trends

“…In contrast, the morphology control, such as 1D nanobelts, [ 383–387 ] or 2D nanosheets, [ 222,388–390 ] was introduced to enhance the photocatalytic activity of Z‐scheme junction photocatalysts. To build a unique 3D morphology, Yang et al [ 227 ] assembled 2D ZnIn 2 S 4 nanosheets onto 1D TiO 2 nanobelts to form a direct Z‐scheme junction ZnIn 2 S 4 /TiO 2 .…”

A Review on Ceo2‐Based Electrocatalyst and Photocatalyst in Energy Conversion

“…Ma et al constructed 0D/1D CdS QDs/CeO 2 nanorod heterojunction and noted the enhanced photocatalytic performance. [ 118 ] The 0D/1D CdS QDs/CeO 2 heterojunctions provide stronger electronic conductivity, improved light‐harvesting, and enhanced photoresponse, which was beneficial for photocatalysts. Z‐scheme heterojunction was widely studied because it enhances the separation efficiency of photogenerated electron–hole pairs and the reduction capacity of electrons participating in HER.…”