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Journal ArticleDOI: 10.1021/ACSSUSCHEMENG.0C08903

In Situ Synthesis of Mo2C Nanoparticles on Graphene Nanosheets for Enhanced Photocatalytic H2-Production Activity of TiO2

02 Mar 2021-ACS Sustainable Chemistry & Engineering (American Chemical Society (ACS))-Vol. 9, Iss: 10, pp 3828-3837
Abstract: Molybdenum carbide (Mo₂C) has been proven to be the most promising candidate for the H₂-evolution cocatalyst due to the similar H⁺-adsorption ability to Pt. However, owing to its limited electrical conductivity, the Mo₂C-modified photocatalysts usually exhibit a low H₂-evolution performance. Considering the perfect electron mobility of graphene nanosheets, in this article, Mo₂C nanoparticles (ca. 5 nm) were in-situ and evenly grown on the reduced graphene oxide (rGO) to prepare the graphene-modified Mo₂C (rGO-Mo₂C) nanoparticles to improve the photocatalytic hydrogen-generation rate of TiO₂. Herein, the rGO-Mo₂C is obtained by the direct calcination of graphene oxide (GO) as the carbon source and (NH₄)₆Mo₇O₂₄ at 800 °C, which is further coupled with the TiO₂ to synthesize the efficient TiO₂/rGO-Mo₂C photocatalyst. The greatest hydrogen-generation activity of TiO₂/rGO-Mo₂C achieved 880 μmol h–¹ g–¹ (AQE = 2.64%), which was 5.5 and 88 times higher than that of TiO₂/rGO and TiO₂, respectively. The boosted performance of TiO₂/rGO-Mo₂C can be attributed to the synergetic action that the rGO nanosheets can act as electron media to promote the photoelectron transfer, and the Mo₂C nanoparticles can serve as active centers to improve the interfacial hydrogen-generation reaction. This work can provide a new synthesis strategy for the design of efficient cocatalysts for potential applications.

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Topics: Graphene (52%)
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Journal ArticleDOI: 10.1016/J.JALLCOM.2021.160165
Cui Kong1, Feng-Jun Zhang1, Yingrui Wang1, Jing Huang1  +1 moreInstitutions (2)
Abstract: In this work, a novel Mo1−xS2 (Mo1−xS2/TiO2) with controllable Mo vacancies was successfully synthesized by simple NaBH4 treatment, which exhibits significantly enhanced hydrogen evolution reaction (HER) activity with lower overpotential and smaller Tafel slope in alkaline electrolyte. Compared with pure TiO2 or MoS2/TiO2, the H2 release rate of Mo1−xS2/TiO2 heterostructure photocatalyst was significantly increased when Mo1−xS2 serves as a co-catalyst. At optimal molar ratio of 2.5:1 Mo1−xS2/TiO2, the H2 release rate achieves 1561 μmol g−1 h−1 in triethanolamine solution, which is approximately 5.3 and 2.7 times of pure TiO2 and MoS2/TiO2, respectively. Through electrochemical analysis and first-principle density functional theory calculations, the faster separation and transfer of photogenerated electron and holes as well as higher HER activity improve the efficiency of photocatalytic hydrogen production. This work opens a new doorway for utilization of defective 2D sheet materials towards solar to H2 conversion.

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Topics: Tafel equation (55%), Overpotential (55%), Hydrogen production (53%) ... read more

3 Citations



Journal ArticleDOI: 10.1016/J.JALLCOM.2021.161425
Lin Dong1, Ping Wang1, Huogen Yu1Institutions (1)
Abstract: Compared with crystalline metal sulfides, amorphous metal sulfides can expose more unsaturated S atoms as hydrogen-production active centers to enhance photocatalytic hydrogen-evolution activity of photocatalysts. Therefore, it is of great significance to explore simple and mild strategies to fabricate new amorphous metal sulfides for improving H2-production performance. In this work, the amorphous BiSx nanodots with the size of 0.5–2 nm as a novel and effective H2-evolution cocatalyst were successfully and homogeneously loaded on TiO2 surface to extremely facilitate the photocatalytic H2-production performance. The BiSx/TiO2 photocatalyst was obtained by an EDTA-assisted two-step process, which was including the adsorption of the Bi(Ш)-EDTA ions on TiO2 and the in-situ formation of amorphous BiSx nanodots. It is found that the BiSx/TiO2(1.0 wt%) photocatalyst achieved the maximum photocatalytic hydrogen-production performance (803.2 μmol h−1 g−1, AQE= 3.86%), which was 83.6 and 1.6 folds of the blank TiO2 and crystalline Bi2S3-modified TiO2 (c-Bi2S3/TiO2), respectively. Importantly, the above amorphous BiSx nanodots can serve as a general cocatalyst to promote the H2-generation activity of other typical photocatalysts (g-C3N4 and CdS). The boosted photocatalytic H2-production performances are attributed to that the amorphous BiSx nanodots can provide more unsaturated active S atoms as the efficient H2-evolution active sites for promoting H2-evolution rate. This study provides a new insight for exploiting novel metal sulfide cocatalyst in the field of photocatalytic hydrogen evolution.

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Topics: Amorphous solid (55%), Nanodot (53%), Amorphous metal (51%) ... read more

1 Citations


Journal ArticleDOI: 10.1016/J.JALLCOM.2021.161850
Zhen Tian1, Xi Yang1, Yufang Chen1, Xuefei Wang1  +4 moreInstitutions (1)
Abstract: Photocatalytic hydrogen desorption from water has been considered to be a more effective way to solve energy shortages. However, the relatively high charge recombination rate and poor recyclability are the principal factors restricting the realistic utilization of photocatalysts. Herein, in order to improve the utilization of photogenerated carriers and the response range of visible light, a ternary composite material LaFeO3/g-C3N4 nanosheets-graphene had been successfully prepared. A series of systematic studies on the structure, microscopic morphology, magnetic properties and photocatalytic hydrogen evolution activity have been carried out. The combination of CNNS, LaFeO3 and graphene in the composites was confirmed by XRD and XPS. SEM and TEM results show that LaFeO3 micro-particles grow uniformly on the CNNS flaps and the graphene is observed to cover the surface of the LaFeO3/CNNS. The optical properties indicate that the absorption edge of the composite material extends to the visible light region. The excellent photocatalytic performance of LFO/CNNS-0.25G composite (1326.5 μmol h−1 g−1) is mainly result in the improved redox capacity and carrier separation due to the tight C–O–Fe bond of Z-scheme heterojunction, meanwhile, the introduction of graphene also broadens the visible light response and accelerates the carrier transport. This research can provide a novel strategy for designing artificial photocatalytic systems with high charge transfer efficiency.

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Topics: Nanosheet (55%), Graphene (54%), Photocatalysis (52%) ... read more

1 Citations



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65 results found


Journal ArticleDOI: 10.1002/ADMA.200802627
Xinchen Wang1, Xiufang Chen2, Arne Thomas1, Xianzhi Fu2  +1 moreInstitutions (2)
27 Apr 2009-Advanced Materials
Abstract: [*] Prof. X. C. Wang, X. F. Chen, Prof. X. Z. Fu Research Institute of Photocatalysis State Key Laboratory Breeding Base of Photocatalysis Fuzhou University, Fuzhou 350002 (PR China) E-mail: xcwang@fzu.edu.cn; xzfu@fzu.edu.cn Prof. X. C. Wang, Dr. A. Thomas, Prof. M. Antonietti Department of Colloid Chemistry Max-Planck Institute of Colloids and Interfaces Research Campus Golm, 14476 Potsdam (Germany)

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Topics: Carbon nitride (69%), Nitride (64%), Hybrid material (58%)

948 Citations


Journal ArticleDOI: 10.1002/ADMA.201303611
Guigang Zhang1, Mingwen Zhang1, Xinxin Ye1, Xiaoqing Qiu1  +2 moreInstitutions (1)
01 Feb 2014-Advanced Materials
Abstract: An optimized and general synthetic strategy based on in-situ iodine modifying of polymeric graphitic carbon nitride is discussed. The as-prepared iodine functionalized g-CN shows enhanced electronic and optical properties, as well as increased photocatalytic activities in an assay of hydrogen evolution.

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Topics: Graphitic carbon nitride (65%)

833 Citations


Open accessJournal ArticleDOI: 10.1038/NCOMMS2152
Jianhua Sun1, Jinshui Zhang1, Mingwen Zhang1, Markus Antonietti2  +2 moreInstitutions (2)
Abstract: Photosynthesis occurs at the thylakoid membrane, which acts as a scaffold, precisely arranging functional proteins and electron carriers. Sun et al. synthesize hollow photosynthetic nanospheres that function as light-harvesting antennae and structured scaffolds that improve photoredox catalysis.

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Topics: Thylakoid (57%), Photoredox catalysis (52%)

710 Citations


Journal ArticleDOI: 10.1002/ADMA.201807660
Aiyun Meng1, Liuyang Zhang1, Bei Cheng1, Jiaguo Yu2  +1 moreInstitutions (2)
01 Jul 2019-Advanced Materials
Abstract: Semiconductor photocatalysis is recognized as a promising strategy to simultaneously address energy needs and environmental pollution. Titanium dioxide (TiO2 ) has been investigated for such applications due to its low cost, nontoxicity, and high chemical stability. However, pristine TiO2 still suffers from low utilization of visible light and high photogenerated-charge-carrier recombination rate. Recently, TiO2 photocatalysts modified by dual cocatalysts with different functions have attracted much attention due to the extended light absorption, enhanced reactant adsorption, and promoted charge-carrier-separation efficiency granted by various cocatalysts. Recent progress on the component and structural design of dual cocatalysts in TiO2 photocatalysts is summarized. Depending on their components, dual cocatalysts decorated on TiO2 photocatalysts can be divided into the following categories: bimetallic cocatalysts, metal-metal oxide/sulfide cocatalysts, metal-graphene cocatalysts, and metal oxide/sulfide-graphene cocatalysts. Depending on their architecture, they can be categorized into randomly deposited binary cocatalysts, facet-dependent selective-deposition binary cocatalysts, and core-shell structural binary cocatalysts. Concluding perspectives on the challenges and opportunities for the further exploration of dual cocatalyst-modified TiO2 photocatalysts are presented.

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Topics: Environmental pollution (52%)

367 Citations


Journal ArticleDOI: 10.1002/ADMA.201704156
Haijing Yan1, Ying Xie1, Yanqing Jiao1, Aiping Wu1  +4 moreInstitutions (1)
01 Jan 2018-Advanced Materials
Abstract: An in situ catalytic etching strategy is developed to fabricate holey reduced graphene oxide along with simultaneous coupling with a small-sized Mo2 N-Mo2 C heterojunction (Mo2 N-Mo2 C/HGr). The method includes the first immobilization of H3 PMo12 O40 (PMo12 ) clusters on graphite oxide (GO), followed by calcination in air and NH3 to form Mo2 N-Mo2 C/HGr. PMo12 not only acts as the Mo heterojunction source, but also provides the Mo species that can in situ catalyze the decomposition of adjacent reduced GO to form HGr, while the released gas (CO) and introduced NH3 simultaneously react with the Mo species to form an Mo2 N-Mo2 C heterojunction on HGr. The hybrid exhibits superior activity towards the hydrogen evolution reaction with low onset potentials of 11 mV (0.5 m H2 SO4 ) and 18 mV (1 m KOH) as well as remarkable stability. The activity in alkaline media is also superior to Pt/C at large current densities (>88 mA cm-2 ). The good activity of Mo2 N-Mo2 C/HGr is ascribed to its small size, the heterojunction of Mo2 N-Mo2 C, and the good charge/mass-transfer ability of HGr, as supported by a series of experiments and theoretical calculations.

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Topics: Graphene oxide paper (53%), Graphite oxide (52%), Heterojunction (51%) ... read more

303 Citations