Unassisted photocatalytic H2O2 production under visible light by fluorinated polymer-TiO2 heterojunction

Hong, Yerin; Cho, Yongjoon; Go, Eun Min; Sharma, Pankaj; Cho, Hyeonjin; Lee, Byongkyu; Lee, Sang Myeon; Park, Sung O; Ko, Myohwa; Kwak, Sang Kyu; Yang, Changduk; Jang, Ji‐Wook

doi:10.1016/j.cej.2021.129346

Cited by 76 publications

(24 citation statements)

References 59 publications

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“…The H 2 O 2 concentration in the aliquot collected at different time intervals from the reaction suspension during light irradiation was measured by the DPD colorimetric method using a UV–visible spectrophotometer (UV-1800, Shimadzu). 18 Depending on the H 2 O 2 concentration, the collected samples were diluted multiple times (10–6000) before its estimation so that the photogenerated H 2 O 2 concentration lies in the calibrated range. To perform the colorimetric estimation of H 2 O 2 in an aqueous solution, 0.4 mL of 0.1 M sodium phosphate buffer (pH 6) was mixed with 1.12 mL of DIW followed by the addition of 1 mL of sample.…”

Section: Methodsmentioning

confidence: 99%

Enhanced H₂O₂ Production via Photocatalytic O₂ Reduction over Structurally-Modified Poly(heptazine imide)

et al. 2022

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Solar H 2 O 2 produced by O 2 reduction provides a green, efficient, and ecological alternative to the industrial anthraquinone process and H 2 /O 2 direct-synthesis. We report efficient photocatalytic H 2 O 2 production at a rate of 73.4 mM h –1 in the presence of a sacrificial donor on a structurally engineered catalyst, alkali metal-halide modulated poly(heptazine imide) (MX → PHI). The reported H 2 O 2 production is nearly 150 and >4250 times higher than triazine structured pristine carbon nitride under UV–visible and visible light (≥400 nm) irradiation, respectively. Furthermore, the solar H 2 O 2 production rate on MX → PHI is higher than most of the previously reported carbon nitride (triazine, tri-s-triazine), metal oxides, metal sulfides, and other metal–organic photocatalysts. A record high AQY of 96% at 365 nm and 21% at 450 nm was observed. We find that structural modulation by alkali metal-halides results in a highly photoactive MX → PHI catalyst which has a broader light absorption range, enhanced light absorption ability, tailored bandgap, and a tunable band edge position. Moreover, this material has a different polymeric structure, high O 2 trapping ability, interlayer intercalation, as well as surface decoration of alkali metals. The specific C≡N groups and surface defects, generated by intercalated MX, were also considered as potential contributors to the separation of photoinduced electron–hole pairs, leading to enhanced photocatalytic activity. A synergy of all these factors contributes to a higher H 2 O 2 production rate. Spectroscopic data help us to rationalize the exceptional photochemical performance and structural characteristics of MX → PHI.

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Section: Methodsmentioning

confidence: 99%

Enhanced H₂O₂ Production via Photocatalytic O₂ Reduction over Structurally-Modified Poly(heptazine imide)

et al. 2022

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“…Photocatalytic H 2 O 2 production is a promising and ideal strategy that involves proton-coupled electron transfer (PCET). [6][7][8][9][10] In this green process, H 2 O 2 can be produced via a one-step two-electron O 2 reduction reaction (OS-2e-ORR, eqn (1)) [11][12][13][14][15] or two-step single-electron O 2 reduction reaction (TS-2e-ORR, eqn (2) and ( 3)). [16][17][18][19][20] For the OS-2e-ORR pathway, 1,4-endoperoxide intermediates are formed, while H 2 O 2 is produced via superoxide radicals for the TS-2e-ORR pathway.…”

Section: Introductionmentioning

confidence: 99%

“…At present, there are many kinds of photocatalysts used in photocatalytic H 2 O 2 production. For example, TiO 2 , 12 BiVO 4 , 21 layered double hydroxides, 22 and polymeric carbon nitride (PCN). 15 O 2 + 2H + + 2e − → H 2 O 2 ; 0.68 V vs. NHEO 2 + H + + e − → ˙OOH; −0.33 V vs. NHE˙OOH + H + + e − → H 2 O 2 ; 1.05 V vs. NHE…”

Section: Introductionmentioning

confidence: 99%

Improved H₂O₂ photogeneration and stability on rational tailored polymeric carbon nitride via enhanced O₂ adsorption

Chen

et al. 2022

J. Mater. Chem. A

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“…Currently, H2O2 is produced via anthraquinone (AQ) process [8][9][10] , direct hydrogen-oxygen reaction 11,12 and oxidation of alcohols 13,14 . These methods either demand high energy input or cause environmental pollution, which significantly hinder their largescale application [15][16][17] . Thus, it is urgent to develop an economic, efficient and eco-friendly method.…”

mentioning

confidence: 99%

“…Moreover, it also reduces our energy reliance on unsustainable fossil fuels and alleviates environmental pollution 15,19,20 . To date, various semiconductors have been developed for photocatalytic H2O2 production, including TiO2 13,16,21 , ZnO [22][23][24] , g-C3N4 [25][26][27] , CdS 28,29 , graphene 30,31 and BiVO4 32 . Among them, ZnO, featured with non-toxicity, stability and earth-abundance, has attracted much interest 33 , but it still suffers from poor absorption of sunlight and fast recombination of photoinduced charge carriers 34 .…”

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confidence: 99%

Enhanced Photocatalytic H<sub>2</sub>O<sub>2</sub> Production over Inverse Opal ZnO@ Polydopamine S-scheme Heterojunctions

Han¹,

Xu²,

Cheng³

et al. 2022

Acta Physico Chimica Sinica

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Photocatalytic H2O2 production is a sustainable and inexpensive process that requires water and gaseous O2 as raw materials and sunlight as the energy source. However, the slow kinetics of current photocatalysts limits its practical application. ZnO is commonly used as a photocatalytic material in the solar-to-chemical conversion, owing to its high electron mobility, nontoxicity, and relatively low cost. The adsorption capacity of H2O2 on the ZnO surface is low, which leads to the continuous production of H2O2. However, its photoresponse is limited to the ultraviolet (UV) region due to its wide bandgap (3.2 eV). Polydopamine (PDA) has emerged as an effective surface functionalization material in the field of photocatalysis due to its abundant functional groups. PDA can be strongly anchored onto the surface of a semiconducting photocatalyst through covalent and noncovalent bonds. The superior properties of PDA served as a motivation for this study. Herein, we prepare an inverse opal-structured porous PDA-modified ZnO (ZnO@PDA) photocatalyst by in situ self-polymerization of dopamine hydrochloride. The crystal structure, morphology, valency, stability, and energy band structure of photocatalysts are characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), field-emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), UV-visible diffuse reflectance spectroscopy (UV-Vis DRS), electrochemical impedance spectroscopy (EIS), Mott-Schottky curve (MS), and electron paramagnetic resonance (EPR). The experimental results showed that electrons in PDA are transferred to ZnO upon contact, which results in an electric field at their interface in the direction from PDA to ZnO. The photoexcited electrons in the ZnO conduction bands flow into PDA, driven by the electric field and bent bands, and are recombined with the holes of the highest occupied molecular orbital of PDA, thereby exhibiting an S-scheme charge transfer. This unique S-scheme mechanism ensures effective electron/hole separation and preserves the strong redox ability of used photocarriers. In addition, the inverse opal structure of ZnO@PDA promotes light-harvesting due to the supposed "slow photon" effect, as well as Bragg diffraction and scattering. Moreover, the enhanced surface area provides a high adsorption capacity and increased active sites for photocatalytic reactions. Therefore, the resulting ZnO@PDA (0.03% (atomic fraction) PDA) exhibits the optimal H2O2 production performance (1011.4 μmol•L −1 •h −1 ), which is 4.4 and 8.9 times higher than pristine ZnO and PDA, respectively. The enhanced performance is ascribed to the improved light absorption, efficient charge separation, and strong redox capability of photocarriers in the S-scheme heterojunction. Therefore, this study provides a novel strategy for the design of inorganic/organic S-scheme heterojunctions for efficient photocatalytic H2O2 production.

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Unassisted photocatalytic H2O2 production under visible light by fluorinated polymer-TiO2 heterojunction

Cited by 76 publications

References 59 publications

Enhanced H₂O₂ Production via Photocatalytic O₂ Reduction over Structurally-Modified Poly(heptazine imide)

Enhanced H₂O₂ Production via Photocatalytic O₂ Reduction over Structurally-Modified Poly(heptazine imide)

Improved H₂O₂ photogeneration and stability on rational tailored polymeric carbon nitride via enhanced O₂ adsorption

Enhanced Photocatalytic H<sub>2</sub>O<sub>2</sub> Production over Inverse Opal ZnO@ Polydopamine S-scheme Heterojunctions

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Unassisted photocatalytic H2O2 production under visible light by fluorinated polymer-TiO2 heterojunction

Cited by 76 publications

References 59 publications

Enhanced H2O2 Production via Photocatalytic O2 Reduction over Structurally-Modified Poly(heptazine imide)

Enhanced H2O2 Production via Photocatalytic O2 Reduction over Structurally-Modified Poly(heptazine imide)

Improved H2O2 photogeneration and stability on rational tailored polymeric carbon nitride via enhanced O2 adsorption

Enhanced Photocatalytic H<sub>2</sub>O<sub>2</sub> Production over Inverse Opal ZnO@ Polydopamine S-scheme Heterojunctions

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Enhanced H₂O₂ Production via Photocatalytic O₂ Reduction over Structurally-Modified Poly(heptazine imide)

Enhanced H₂O₂ Production via Photocatalytic O₂ Reduction over Structurally-Modified Poly(heptazine imide)

Improved H₂O₂ photogeneration and stability on rational tailored polymeric carbon nitride via enhanced O₂ adsorption