S‐Scheme Heterojunction TiO₂/CdS Nanocomposite Nanofiber as H₂‐Production Photocatalyst

Abstract

One-dimensional (1D) nanostructured photocatalyst is a promising candidate for hydrogen (H 2 ) generation, which can be used to deal with the energy crisis. Herein, novel 1D TiO 2 /CdS wellhybridized nanofibers (NFs) were synthesized via in situ electrospinning method. These 1D hybrid NFs showed a high H 2production rate of 2.32 mmol h À 1 g À 1 with an apparent quantum efficiency of 10.14 %, which was 35-fold higher than that of pristine TiO 2 NFs. X-ray photoelectron spectroscopy (XPS) analysis and density functional theory calculation implied that the electrons transferred from CdS to TiO 2 upon hybridization and created an internal electric field (IEF) pointing from CdS to TiO 2 . This IEF drove the photoexcited electrons in TiO 2 to transfer toward CdS upon light irradiation as revealed by in situ irradiated XPS analysis, suggesting that a step-scheme (Sscheme) heterojunction was formed in the TiO 2 /CdS nanohybrids and greatly promoted the separation of electron-hole pairs to foster efficient H 2 photogeneration. The significant enhancement of photocatalytic activity was also benefited from the easy transfer for electrons in the 1D well-distributed nanostructure of nanohybrids. This

Fabrication of Graphene Quantum Dots Modified BiOI/PAN Flexible Fiber with Enhanced Photocatalytic Activity

“…Beside immobilization of BiOI, coupling BiOI with a nonmetal co-catalyst to construct an S-scheme heterojunction is also an effective way to improve its performance 11, [29][30][31][32][33][34][35][36][37] . Usually, semiconductors with narrow band gap are employed as the cocatalyst in building S-scheme heterojunctions, such as CdS, MoS2, C3N4, and Bi2O3 [38][39][40][41] . In fact, graphene quantum dots (GQDs) can also act as the co-catalyst in constructing S-scheme heterojunctions.…”

Nanostructured CdS for efficient photocatalytic H2 evolution: A review

“…They found that the formation of Z-scheme heterostructures between ZnO and CdS could effectively prolong the lifetime of photogenerated e − , reaching a 14-fold improvement in H 2 evolution performance compared with that of pure CdS. Since then, numerous direct Z-scheme CdS-based photocatalysts have been applied in photo-catalytic H 2 generation applications [334], including CdS/ WO 3−x [222], FeC 2 O 4 •2H 2 O/CdS [335], CdS/WO 3 [165,301], CdS/MoO 3−x [336], CdS/g-C 3 N 4 [337,338], CoWO 4 /CdS [44], CdS/Fe 2 O 3 [179], CdS/BiVO 4 [339], TiO 2 /CdS [329,340,341], CdS/CdWO 4 [219,342], ZnO/ CdS [306] and CdS/PI [217]. In our previous study, we reported the fabrication of 2D/2D CdS/g-C 3 N 4 direct Zscheme heterojunction nanocomposites through the insitu growth of 2D CdS NSs on 2D g-C 3 N 4 NSs [338].…”

2D/2D heterostructured photocatalyst: Rational design for energy and environmental applications

“…The H 2 evolution rate of BP/MBWO can reach 21,042 μmol g −1 , which is 9.15 times that of pristine MBWO. More recently, a new step-scheme (S-scheme) heterojunction concept was proposed based on the Z-scheme photocatalysts [116,[154][155][156][157][158]. As shown in Fig.…”