Photogenerated Defect‐Transit Dual S‐Scheme Charge Separation for Highly Efficient Hydrogen Production

Abstract

The rational design of a step‐scheme (S‐scheme) heterojunctions in hybrid semiconductors by avoiding unwanted charge transport paths is considered as an attractive way to achieve high photocatalytic activity in hydrogen evolution reaction (HER). Here, a dual S‐scheme heterojunction formed in the lychee‐shaped W18O49/CdWO4/CdS nanostructures is proposed for improving the photocatalytic performance in HER under visible light irradiation. The remarkable activity in photocatalytic HER of W18O49/CdWO4/CdS is attributed to the unique structure and effective charge separation by the photoinduced defect‐transit dual S‐scheme mechanism and strong internal electric field. The measurements of X‐ray photoelectron spectroscopy (XPS), femtosecond transient absorption (fs‐TA) spectroscopy, and electron paramagnetic resonance (EPR) further confirm the photoinduced carrier transfer pathways following the dual S‐scheme mechanism. This research can provide a new strategy for designing the dual S‐scheme heterojunctions to improve photocatalytic performance through the defect band structure engineering.

Few‐Layer Fullerene Network for Photocatalytic Pure Water Splitting into H2 and H2O2

“…Moreover, the DMPO (5,5‐dimethyl‐1‐pyrroline N‐oxide) spin‐trapping EPR (electron paramagnetic resonance) technique was used to in situ monitor the reaction intermediates with the few‐layer C 60 sample as the catalyst in pure water. EPR results in Figure S13 show the typical peaks of DMPO‐⋅OH and DMPO‐⋅O 2 − after visible‐light irradiation, confirming the existence of ⋅OH and ⋅O 2 − in this photocatalytic system [25] . H 2 O was oxidized by the photogenerated holes from the few‐layer C 60 sample to form ⋅OH, which subsequently reacted with each other to produce H 2 O 2 .…”

Isotype heterojunction: tuning the heptazine/triazine phase of crystalline nitrogen-rich C3N5 towards multifunctional photocatalytic applications

“…In comparison, 4 characteristic peaks of the DMPO-˙OH adducts can be found for the CC3N5-500 sample, indicating that these radicals are generated during photocatalytic reactions. 72 The signals for active radicals for ˙O 2 − were also observed for CC3N5-500 (Fig. S8b, ESI†), demonstrating that they are part of the photocatalytic mechanism.…”

Unlocking the Charge‐Migration Mechanism in S‐Scheme Junction for Photoreduction of Diluted CO2 with High Selectivity

“…The implementation of an S‐scheme heterojunction, consisting of both reductive and oxidative photocatalysts, has emerged as a promising approach to enhance photocatalytic efficiency. [ 27–35 ] Unlike conventional photosystems, the S‐scheme architecture induces internal electric fields, band bending, and coulombic attraction, promoting efficient charge transfer and overall photocatalytic effectiveness. Despite the potential advantages, inadequate interfacial contact and unclear mechanisms governing long‐term carrier transfer remain significant impediments.…”