A Z-scheme mechanism of N-ZnO/g-C3N4 for enhanced H2 evolution and photocatalytic degradation

Liu, Yujie; Liu, Haixia; Zhou, Huamin; Li, Tianduo; Zhang, Lunan

doi:10.1016/j.apsusc.2018.10.027

Cited by 173 publications

(56 citation statements)

References 37 publications

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“…Regarding composite sample patterns, the (002) and (011) peaks of LaO were detected at 29.37 • and 30.36 • , respectively. The (002) peak of CN in composite samples indexed to 27.7 • [25]. All these peaks had a slight red-shift and demonstrated the heterojunction formed between the (002) facet of CN and the (011) facet peak of LaO, which further illustrated that the heterojunction photocatalysts were fabricated successfully [26].…”

Section: Xrd Analysismentioning

confidence: 82%

Fabrication of La2O3/g-C3N4 Heterojunction with Enhanced Photocatalytic Performance of Tetracycline Hydrochloride

Zhu

Xia

et al. 2021

Crystals

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In this study, La2O3/g-C3N4 heterojunction photocatalysts doped with different dosages of La2O3 were constructed by a facile ultrasound-assisted calcination approach. The as-prepared photocatalysts were characterized by XRD, FTIR, FESEM, TEM, XPS, PL and DRS to verify the composite photocatalysts’ purity and to investigate their structural, morphological and elemental composition, and their energy band. According to the results, a type of pure rod–sheet-shaped, heterostructured nanoparticle was successfully obtained. Decorated with 10% La2O3, 2 g/L of the composite sample had a 93% degradation rate for 20 mg/L tetracycline hydrochloride within 2 h under visible light at a pH of 7. After four successive photocatalytic runs, satisfactory stability and reusability was exhibited, with 70% of the tetracycline hydrochloride being removed in the final experiment. Electrons (e−), photogenerated holes (h+), superoxide radical anions (·O2−) and hydroxyl radicals (·OH) were the fundamental active species during the photocatalytic process and were investigated via quenching experiments. Furthermore, possible photocatalytic mechanisms were analyzed in this work.

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Section: Xrd Analysismentioning

confidence: 82%

Fabrication of La2O3/g-C3N4 Heterojunction with Enhanced Photocatalytic Performance of Tetracycline Hydrochloride

Zhu

Xia

et al. 2021

Crystals

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“…6b). The CB position (ECB) and VB position (EVB) of WO and PCN are based on the following formula 52 :…”

Section: Optical Property Analysismentioning

confidence: 99%

Construction of 1D/2D W18O49/Porous g-C3N4 S-Scheme Heterojunction with Enhanced Photocatalytic H2 Evolution

黄悦¹,

梅飞飞²,

张金锋³

et al. 2021

Acta Physico Chimica Sinica

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Photocatalytic hydrogen production is an effective strategy for addressing energy shortage and converting solar energy into chemical energy. Exploring effective strategies to improve photocatalytic H2 production is a key challenge in the field of energy conversion. There are numerous oxygen vacancies on the surface of non-stoichiometric W18O49 (WO), which result in suitable light absorption performance, but the hydrogen evolution effect is not ideal because the band potential does not reach the hydrogen evolution potential. A suitable heterojunction is constructed to optimize defects such as high carrier recombination rate and low photocatalytic performance in a semiconductor. Herein, 2D porous carbon nitride (PCN) is synthesized, followed by the in situ growth of 1D WO on the PCN to realize a step-scheme (S-scheme) heterojunction. When WO and PCN are composited, the difference between the Fermi levels of WO and PCN leads to electron migration, which balances the Fermi levels of WO and PCN. Electron transfer leads to the formation of an interfacial electric field and bends the energy bands of WO and PCN, thereby resulting in the recombination of unused electrons and holes while leaving used electrons and holes, which can accelerate the separation and charge transfer at the interface and endow the WO/PCN system with better redox capabilities. In addition, PCN with a porous structure provides more catalytic active sites. The photocatalytic performance of the sample can be investigated using the amount of hydrogen released. Compared to WO and PCN, 20%WO/PCN composite has a higher H2 production rate (1700 µmol•g −1 •h −1 ), which is 56 times greater than that of PCN (30 µmol•g −1 •h −1 ). This study shows the possibility of the application of S-scheme heterojunction in the field of photocatalytic H2 production.

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“…As above discussed in the applications of different type photocatalytic systems, pure inorganic semiconductors (usually displaying efficient photoactivity) and inorganic-organic hybrid systems have been widely utilized in photocatalytic energy conversion fields [247][248][249][250][251][252][253][254][255][256][257][258][259][260] . While, the organic semiconductors with a large π-conjugated stucture and adjustable photoelectric properties are key route 188, [261][262][263][264][265] .…”

Section: N2 Photofixationmentioning

confidence: 99%

“…Light absorption, charge separation/transfer and surface chemical reactions determine the overall efficiency of photocatalytic systems [253][254][255][256][257][258][259][260][261][262][263][264][265][266][267][268][269][270] , and the surface redox reactions can be optimized by cocatalyst loading and other surface modification approach [271][272][273][274][275][276][277][278][279][280][281] .…”

Section: Surface Chemical Modificationmentioning

confidence: 99%

Review of Z-Scheme Heterojunctions for Photocatalytic Energy Conversion

Liu¹,

Chen²,

Li³

et al. 2020

Acta Physico Chimica Sinica

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Inspired by the photosynthesis of green plants, various artificial photosynthetic systems have been proposed to solve the energy shortage and environmental problems. Water photosplitting, carbon dioxide photoreduction, and nitrogen photofixation are the main systems that are used to produce solar fuels such as hydrogen, methane, or ammonia. Although conducting artificial photosynthesis using man-made semiconducting materials is an ideal and potential approach to obtain solar energy, constructing an efficient photosynthetic system capable of producing solar fuels at a scale and cost that can compete with fossil fuels remains challenging. Therefore, exploiting the efficient and low-cost photocatalysts is crucial for boosting the three main photocatalytic processes (light-harvesting, surface/interface catalytic reactions, and charge generation and separation) of artificial photosynthetic systems. Among the various photocatalysts developed, the Z-scheme heterojunction composite system can increase the light-harvesting ability and remarkably suppress charge carrier recombination; it can also promote surface/interface catalytic reactions by preserving the strong reductive/oxidative capacity of the photoexcited electrons/holes, and therefore, it has attracted considerable attention. The continuing progress of Z-scheme nanostructured heterojunctions, which convert solar energy into chemical energy through photocatalytic processes, has witnessed the importance of these heterojunctions in further improving the overall efficiency of photocatalytic reaction systems for producing solar fuels. This review summarizes the progress of Z-scheme heterojunctions as photocatalysts and the advantages of using the direct Z-scheme heterojunctions over the traditional type II, all-solid-state Z-schemel, and liquid-phase Z-scheme ones. The basic principle and corresponding mechanism of the two-step excitation are illustrated. In particular, applications of various types of Z-scheme nanostructured materials (inorganic, organic, and inorganic-organic hybrid materials) in photocatalytic energy conversion and different controlling/engineering strategies (such as extending the spectral absorption region, promoting charge transfer/separation and surface chemical modification) for enhancing the photocatalytic efficiency in the last five years are highlighted. Additionally, characterization methods (such as sacrificial reagent experiment, metal loading, radical trapping testing, in situ X-ray photoelectron spectroscopy, photocatalytic reduction experiments, Kelvin probe force microscopy, surface photovoltage spectroscopy, transient absorption spectroscopy, and theoretical calculation) of the Z-scheme photocatalytic mechanism, and the assessment criteria and methods of the photocatalytic performance are discussed. Finally, the challenges associated with Z-scheme heterojunctions and the possible growing trend are presented. We believe that this review will provide a new understanding of the breakthrough direction of photocatalytic performance and p...

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A Z-scheme mechanism of N-ZnO/g-C3N4 for enhanced H2 evolution and photocatalytic degradation

Cited by 173 publications

References 37 publications

Fabrication of La2O3/g-C3N4 Heterojunction with Enhanced Photocatalytic Performance of Tetracycline Hydrochloride

Fabrication of La2O3/g-C3N4 Heterojunction with Enhanced Photocatalytic Performance of Tetracycline Hydrochloride

Construction of 1D/2D W<sub>18</sub>O<sub>49</sub>/Porous g-C<sub>3</sub>N<sub>4</sub> S-Scheme Heterojunction with Enhanced Photocatalytic H<sub>2</sub> Evolution

Review of Z-Scheme Heterojunctions for Photocatalytic Energy Conversion

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