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Small-sized Ni(1 1 1) particles in metal-organic frameworks with low over-potential for visible photocatalytic hydrogen generation

Paper ID Volume ID Publish Year Pages File Format Full-Text
44922 46380 2016 14 PDF Available
Title
Small-sized Ni(1 1 1) particles in metal-organic frameworks with low over-potential for visible photocatalytic hydrogen generation
Abstract

•Small-sized Ni NPs in MOF-5 as a co-catalyst for visible photocatalytic H2 evolution.•Ni@MOF-5 exhibited the excellent photocatalytic activity and stability.•Ni@MOF-5 material showed similar a low over-potential of −0.37 V with Pt@MOF-5.•Introduction of Ni(1 1 1) NPs promoted the electrons transfer from the MOF-5.•MOF-5 in facilitating the transfer of photogenerated electrons.

The development of an advanced co-catalyst is critical for improving the efficiency of the photocatalytic hydrogen evolution reaction. Noble metals (such as Pt) have been identified to be the most active co-catalyst for this reaction since they exhibit significantly low over-potential. However, their low-abundance, high cost, its scale-up setup usage is impeditive. Here, we reported that high efficient small-sized nickel particles embedded in the frameworks of MOF-5 as a co-catalyst with low over-potential for visible photocatalytic hydrogen evolution. The electrochemical measurements showed a low over-potential of −0.37 V, which have the similar over-potential as Pt@MOF-5. Such low over-potential is attributed to their high dispersion (41.8%), small-sized nickel particles (∼9 nm), and high specific surface area of MOF-5 (2973 m2/g). As evidenced by electrochemical impedance spectra (EIS) measurements, Ni nanoparticles with exposed (1 1 1) facet were more benefited the electrons transfer from MOF-5 than that of (2 0 0) facet one. In addition, Ni@MOF-5 exhibited the larger transient photocurrent and longer fluorescence lifetime. These results led to the high photocatalytic activities and stability for hydrogen evolution sensitized by Eosin Y (EY) over Ni@MOF-5. The rate of hydrogen evolution reached 30.22 mmol h−1 g−1[Ni] (at pH 11) over Ni@MOF-5 irradiated under visible light irradiation (λ ≥420 nm) in 2 h. The apparent quantum efficiency (AQE) of 16.7% over EY-Ni@MOF-5 was achieved at 430 nm. MOF-5 might promote the photogenerated electrons transfer from excited EY to the hydrogen evolution active sites (Ni), and consequently enhance photocatalytic hydrogen evolution efficiency.

Graphical abstractMOF-5 was explored as a support for catalyst of H2 evolution after anchored Ni particle. Very high dispersion of Ni(41.8%) and the Ni average crystallite size was 9 nm, due to the high SBET of Ni@MOF-5 (2961 m2/g). Ni@MOF-5 exhibits the similar over-potential (−0.37 V) as Pt@MOF-5. Ni NPs with exposed (1 1 1) facets was more benefited the electrons transfer from MOF-5 to Ni than that of (2 0 0) facets. Moreover, Ni@MOF-5 exhibits the larger transient photocurrent, longer fluorescence lifetime, high photocatalytic activities and excellent stability.Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
Small-sized Ni(1 1 1) particles; Metal-organic frameworks; Low over-potential; Visible photocatalytic hydrogen generation
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Small-sized Ni(1 1 1) particles in metal-organic frameworks with low over-potential for visible photocatalytic hydrogen generation
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volume 190, 5 August 2016, Pages 12–25
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
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