Charge transfer in SnS2/Na0.9Mg0.45Ti3.55O8 heterojunction in photocatalytic process

Wang, Jing-Zhou; Zhou, Ziyang; Dai, Yong-Jie; Zhou, Jianping; Lv, Xiaogong

doi:10.1088/1361-6528/abba9a

Cited by 1 publication

(8 citation statements)

References 56 publications

(74 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The Kelvin probe force microscopy (KPFM) mounted on the scanning probe microscope (SPM, Dimension Icon, Bruker Nano Inc.) was employed to measure the surface potential in the dark and under light illumination with different wavelengths to explore the charge transfer in heterojunctions [29,30,40]. The powder was fixed on an FTO conductive glass substrate with a silver paste.…”

Section: Kpfm Measurementmentioning

confidence: 99%

“…Whereas, the binding energies of Cu 2p, Ni 2p and Co 2p in heterojunctions shift oppositely in comparison with those in the pure CuO, NiO and Co 3 O 4 . These binding energy variations are attributed to the different electron densities, which are caused by the electron migration across the interface, providing a powerful proof for the heterojunction with strong interfacial interaction rather than a simple physical mixture [25,30,42]. Clearly, the experimental results imply the electrons transfer from CuO to NMTO through the interface of CuO/NMTO heterojunction, while from NMTO to NiO and Co 3 O 4 through the interface of NiO/NMTO and Co 3 O 4 /NMTO heterojunctions, respectively, resulting in built-in electric fields at the heterojunction interfaces [26,28].…”

Section: Charge Transfer In Heterojunctionmentioning

confidence: 99%

“…The band mutation at the interface will affect the carrier diffusion. In addition, the lattice mismatch between two semiconductors introduces a large number of hanging bonds and defects at the interface to form a high-density interface state, which can capture the charge carriers [29,30], although the interface defects can be reduced during the preparation due to the principle of minimum energy. Unfortunately, the role of the interface state was ignored in the reported research.…”

Section: Introductionmentioning

confidence: 99%

“…The KPFM has a high spatial resolution on a nanometer scale to obtain the surface potential in submillivolt sensitivity at different surface positions for the charge distribution information [31,32]. Recently, the KPFM was used to characterize the carrier redistribution under light illumination to provide direct evidence about the charge separation and migration [29,30,[33][34][35][36][37][38].…”

Section: Introductionmentioning

confidence: 99%

“…Importantly, NMTO exhibits long hexagonal nanosheets, which can be easily distinguished by the KPFM. Schottky and n-n type heterojunctions have been constructed on the NMTO nanosheets to improve its photocatalytic performance, and the carrier migration in metal oxide/NMTO [40], TiO 2 /NMTO [29], SnS 2 /NMTO [30] under light illumination was probed by the KPFM. Here, three typical p-type semiconductors CuO, NiO and Co 3 O 4 with different energy band characteristics were loaded on the NMTO nanosheets to form heterojunctions.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Direct observation of carrier migration in heterojunctions to discuss the p–n and direct Z-scheme heterojunctions

Yang¹,

Zhou²,

Chen³

et al. 2022

Nanotechnology

Self Cite

View full text Add to dashboard Cite

Type II p-n heterojunction and direct Z-scheme heterojunction are identical staggered band alignments, but were reported ambiguously in many composite photocatalysts because their carriers migrate in opposite directions. In this research, metal oxides CuO, NiO and Co3O4-based heterojunctions with Na0.9Mg0.45Ti3.55O8 (NMTO) were synthesized via a simple hydrothermal method. The CuO/NMTO heterojunction was demonstrated as a direct Z-scheme heterojunction, whereas the NiO/NMTO and Co3O4/NMTO heterojunctions showed type II p-n band alignment, distinguished by the direct observation of carrier migration under light illumination, and confirmed by the X-ray photoelectron spectroscopy, Mott-Schottky measurements, ultraviolet photoelectron spectra and capture experiments. These all heterojunctions enjoyed better photocatalytic performance to degrade methylene blue and antibiotics (Enrofloxacin, Metronidazole and tetracycline) than the pure NMTO, attributed to their effective separation of the photoinduced electron-hole pairs owing to the staggered band alignment. Prominently, the NiO/NMTO and Co3O4/NMTO p-n heterojunctions exhibited superior degradation ability to the CuO/NMTO Z-scheme heterojunction. The initial relative Fermi position of two semiconductors is the prerequisite to determine whether the p-n heterojunction or direct Z-scheme heterojunction is built because the electrons diffuse from one semiconductor with a higher Fermi level to another with a lower Fermi level while the holes diffuse reversely until a united Fermi level when they combine. The built-in electric field at the heterojunction interface is determined by the difference in the initial Fermi levels or work functions of two semiconductors, regulating the separation ability of photogenerated electrons and holes to affect the photocatalytic performance. Thus, the high difference in the initial Fermi levels of semiconductors is crucial in the development of heterojunctions with staggered band alignment to obtain high performance in photocatalytic reactions.

show abstract

Section: Kpfm Measurementmentioning

confidence: 99%