Verifying the Charge‐Transfer Mechanism in S‐Scheme Heterojunctions Using Femtosecond Transient Absorption Spectroscopy

Abstract

The S-scheme heterojunction is flourishing in photocatalysis because it concurrently realizes separated charge carriers and sufficient redox ability. Steady-state charge transfer has been confirmed by other methods. However, an essential part, the transfer dynamics in Sscheme heterojunctions, is still missing. To compensate, a series of cadmium sulfide/pyrene-alt-difluorinated benzothiadiazole heterojunctions were constructed and the photophysical processes were investigated with femtosecond transient absorption spectroscopy. Encouragingly, an interfacial charge-transfer signal was detected in the spectra of the heterojunction, which provides solid evidence for S-scheme charge transfer to complement the results from well-established methods. Furthermore, the lifetime for interfacial charge transfer was calculated to be ca. 78.6 ps. Moreover, the S-scheme heterojunction photocatalysts exhibit higher photocatalytic conversion of 1,2-diols and H 2 production rates than bare cadmium sulfide.

Interfacial phosphate-like “bridge” mediates bulk charge and surface oxygenated-intermediate migration for efficient photoelectrochemical water splitting

“…Specifically, the VB holes of ZIS were recombined with the CB electrons of CdS, and resulted in the weakening of the negative signal at 500 nm. 31 Moreover, ZIS–P/CdS exhibited the slowest decay in 0.5–10 ps for the Z-type built-in electric field. The decay kinetic curves of the photoanodes were further fitted by the three exponential functions.…”

Indanone-based conjugated polymers enabling ultrafast electron transfer for visible light-driven hydrogen evolution from water

“…Fitting the data with three-exponential functions revealed that all three photocatalysts exhibited two short-lived components and one long-lived component in their decay profiles. 11,67–69 The short-lived components τ 1 , within the picosecond timescale, are likely to signify electron transfer to Pt sites. Conversely, the long-lived component τ 3 is attributed to charge carrier recombination.…”

“…11,[67][68][69] The short-lived components s 1 , within the picosecond timescale, are likely to signify electron transfer to Pt sites. Conversely, the long-lived component s 3 is attributed to charge carrier recombination.…”

WO3 Nanosheet/ZnIn2S4 S-Scheme Heterojunctions for Enhanced CO2 Photoreduction

“…In recent years, researchers have been carrying out extensive research in the field of construction of nanophotocatalysts. For example, heteroatom doping, surface defect modification, plasma modification, construction of heterojunction, and other strategies have been researched for enhancement of the catalytic ability of pure phase catalysts at the nanoscale. − Among them all, construction of nanoheterojunction with a specific nanostructure is a useful method for researchers to improve the CO 2 photoreduction performance, due to its easy operation, high light utilization rate, and other advantages. In our previous research, we prepared a 2D/1D/2D g-C 3 N 4 /CeO 2 /rGO ternary composite catalyst for the CO 2 photoreduction reaction.…”