S-Scheme α-Fe2O3/TiO2 Photocatalyst with Pd Cocatalyst for Enhanced Photocatalytic H2 Production Activity and Stability

Bootluck, Weerapong; Chittrakarn, Thawat; Techato, Kuaanan; Jutaporn, Panitan; Khongnakorn, Watsa

doi:10.1007/s10562-021-03873-5

Cited by 28 publications

(8 citation statements)

References 84 publications

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“…As observed in the electron paramagnetic resonance (EPR) signals of superoxide anion radicals ( * O 2 À ) and hydroxyl radicals ( * OH) (Figures S11a and S11b), both T and NZCS show the DMPO-* O 2 À peaks. This suggests that both of them possess a more negative conduction band (CB) than O 2 / * O 2 À at À 0.33 V. [21] The EPR spectrum of T exhibits distinct DMPO-* OH peaks due to its valence band (VB) being more positive than that of OH À / * OH (2.69 eV). In contrast, the EPR signal of NZCS is nearly undetectable, indicating that NZCS is incapable of generating * OH.…”

Section: Methodsmentioning

confidence: 99%

Rapid Charge Transfer Endowed by Interfacial Ni‐O Bonding in S‐scheme Heterojunction for Efficient Photocatalytic H₂ and Imine Production

He,

Xiao,

Wan

et al. 2023

Angew Chem Int Ed

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Cooperative coupling of H2 evolution with oxidative organic synthesis is promising in avoiding the use of sacrificial agents and producing hydrogen energy with value‐added chemicals simultaneously. Nonetheless, the photocatalytic activity is obstructed by sluggish electron‐hole separation and limited redox potentials. Herein, Ni‐doped Zn0.2Cd0.8S quantum dots are chosen after screening by DFT simulation to couple with TiO2 microspheres, forming a step‐scheme heterojunction. The Ni‐doped configuration tunes the highly active S site for augmented H2 evolution, and the interfacial Ni−O bonds provide fast channels at the atomic level to lower the energy barrier for charge transfer. Also, DFT calculations reveal an enhanced built‐in electric field in the heterojunction for superior charge migration and separation. Kinetic analysis by femtosecond transient absorption spectra demonstrates that expedited charge migration with electrons first transfer to Ni2+ and then to S sites. Therefore, the designed catalyst delivers drastically elevated H2 yield (4.55 mmol g−1 h−1) and N‐benzylidenebenzylamine production rate (3.35 mmol g−1 h−1). This work provides atomic‐scale insights into the coordinated modulation of active sites and built‐in electric fields in step‐scheme heterojunction for ameliorative photocatalytic performance.

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Section: Methodsmentioning

confidence: 99%

Rapid Charge Transfer Endowed by Interfacial Ni‐O Bonding in S‐scheme Heterojunction for Efficient Photocatalytic H₂ and Imine Production

He,

Xiao,

Wan

et al. 2023

Angew Chem Int Ed

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“…Metal oxide heterojunctions can be categorized into type I, II, and III depending on how the band edges of two semiconductors relate to one another . Moreover, different charge carrier transfer routes have been proposed, among which Z and S schemes are the most popular. , …”

Section: Introductionmentioning

confidence: 99%

Scavenger-Supported Photocatalytic Evidence of an Extended Type I Electronic Structure of the TiO₂@Fe₂O₃ Interface

Trenczek-Zając

Synowiec

Zakrzewska

et al. 2022

ACS Appl. Mater. Interfaces

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Heterostructures of TiO 2 @Fe 2 O 3 with a specific electronic structure and morphology enable us to control the interfacial charge transport necessary for their efficient photocatalytic performance. In spite of the extensive research, there still remains a profound ambiguity as far as the band alignment at the interface of TiO 2 @Fe 2 O 3 is concerned. In this work, the extended type I heterojunction between anatase TiO 2 nanocrystals and α-Fe 2 O 3 hematite nanograins is proposed. Experimental evidence supporting this conclusion is based on direct measurements such as optical spectroscopy, X-ray photoemission spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy (HRTEM), and the results of indirect studies of photocatalytic decomposition of rhodamine B (RhB) with selected scavengers of various active species of OH • , h • , e − , and • O 2 − . The presence of small 6−8 nm Fe 2 O 3 crystallites at the surface of TiO 2 has been confirmed in HRTEM images. Irregular 15−50 nm needle-like hematite grains could be observed in scanning electron micrographs. Substitutional incorporation of Fe 3+ ions into the TiO 2 crystal lattice is predicted by a 0.16% decrease in lattice parameter a and a 0.08% change of c, as well as by a shift of the Raman E g(1) peak from 143 cm −1 in pure TiO 2 to 149 cm −1 in Fe 2 O 3 -modified TiO 2 . Analysis of O 1s XPS spectra corroborates this conclusion, indicating the formation of oxygen vacancies at the surface of titanium(IV) oxide. The presence of the Fe 3+ impurity level in the forbidden band gap of TiO 2 is revealed by the 2.80 eV optical transition. The size effect is responsible for the absorption feature appearing at 2.48 eV. Increased photocatalytic activity within the visible range suggests that the electron transfer involves high energy levels of Fe 2 O 3 . Well-programed experiments with scavengers allow us to eliminate the less probable mechanisms of RhB photodecomposition and propose a band diagram of the TiO 2 @Fe 2 O 3 heterojunction.

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“…[5][6][7] However, the PEC property of the α-Fe 2 O 3 photoanode is unsatisfactory in practical application and is affected by the following defects, for instance, slow water oxidation kinetics, serious bulk and surface recombination of electron and hole, and short hole diffusion distance. [8][9][10] Considering the above, the targeted modification of α-Fe 2 O 3 is necessary to increase its PEC activity by: (i) nanoengineering α-Fe 2 O 3 to compensate for the short minority carrier diffusion length by maximizing the semiconductor-electrolyte interface; 11,12 (ii) increasing the electroconductivity by elemental doping (e.g., F, Ti, Ta); 7,13,14 (iii) passivating the surface states by the decoration of a metal oxide transition layer; 15,16 (iv) heterostructure engineering by utilizing the synergistic effects of different semiconductors; 17,18 and (v) loading cocatalyst to improve the water oxidation kinetics. 19 The state-of-the-art cocatalysts mainly include transition metal oxides (CoO X ), 20 hydroxides (Ni(OH) 2 ), 21 oxyhydroxides (FeOOH, NiOOH, InOOH), [21][22][23] and phosphates (CoPi, FeP).…”

Section: Introductionmentioning

confidence: 99%

Surface-oxidized titanium diboride as cocatalyst on hematite photoanode for solar water splitting

Liang

Chen

et al. 2022

CrystEngComm

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S-Scheme α-Fe2O3/TiO2 Photocatalyst with Pd Cocatalyst for Enhanced Photocatalytic H2 Production Activity and Stability

Cited by 28 publications

References 84 publications

Rapid Charge Transfer Endowed by Interfacial Ni‐O Bonding in S‐scheme Heterojunction for Efficient Photocatalytic H₂ and Imine Production

Rapid Charge Transfer Endowed by Interfacial Ni‐O Bonding in S‐scheme Heterojunction for Efficient Photocatalytic H₂ and Imine Production

Scavenger-Supported Photocatalytic Evidence of an Extended Type I Electronic Structure of the TiO₂@Fe₂O₃ Interface

Surface-oxidized titanium diboride as cocatalyst on hematite photoanode for solar water splitting

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S-Scheme α-Fe2O3/TiO2 Photocatalyst with Pd Cocatalyst for Enhanced Photocatalytic H2 Production Activity and Stability

Cited by 28 publications

References 84 publications

Rapid Charge Transfer Endowed by Interfacial Ni‐O Bonding in S‐scheme Heterojunction for Efficient Photocatalytic H2 and Imine Production

Rapid Charge Transfer Endowed by Interfacial Ni‐O Bonding in S‐scheme Heterojunction for Efficient Photocatalytic H2 and Imine Production

Scavenger-Supported Photocatalytic Evidence of an Extended Type I Electronic Structure of the TiO2@Fe2O3 Interface

Surface-oxidized titanium diboride as cocatalyst on hematite photoanode for solar water splitting

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Rapid Charge Transfer Endowed by Interfacial Ni‐O Bonding in S‐scheme Heterojunction for Efficient Photocatalytic H₂ and Imine Production

Rapid Charge Transfer Endowed by Interfacial Ni‐O Bonding in S‐scheme Heterojunction for Efficient Photocatalytic H₂ and Imine Production

Scavenger-Supported Photocatalytic Evidence of an Extended Type I Electronic Structure of the TiO₂@Fe₂O₃ Interface