Opto—acoustic determination of absolute quantum yields in flourescent solutions

In the photolysis of copper(II)-chloride-alcohol-acetonitrile systems (cCu = 1 mmol l-1, copper(II)-to-chloride molar ratio 1 : 2 to 1 : 8, 10% (v/v) alcohol), Cu(II) is reduced to Cu(I), and methanol, ethanol, 1-propanol, or 1-butanol is oxidized to the corresponding aldehyde, 2-propanol to acetone. In the case of 1-propanol and 1-butanol, chlorinated aldehydes are formed in addition too. The measured quantum yields of the photoreduction of Cu(II) to Cu(I) lay in the range of ΦCu(I) = 4.5 to 40 mmol einstein-1, the absolute quantum yields of the alcohol oxidation products were 2.3 to 47 mmol einstein-1. The photoactive components are chlorocupric complexes [CuClx](2-x)+ (x = 1-4). The presence of complexes with a higher number of chloroligands in the coordination sphere (x = 3, 4) brings about a decrease in the Cu(II) photoreduction rate. The decrease in the photoreduction rate observed in the presence of dioxygen is explained in terms of re-oxidation of copper(I) by the latter, resulting in an increase in the concentration of the photochemically active cupric complexes. The catalytic aspects of the systems in question are discussed with respect to this effect.

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Determination of reaction quantum yields of photochromic fulgides using mid-IR spectroscopy: quantitative evaluation and normal mode analysis

Chemical Physics Letters ◽

10.1016/s0009-2614(99)01134-3 ◽

1999 ◽

Vol 314 (1-2) ◽

pp. 65-72 ◽

Cited By ~ 14

Author(s):

M Seibold ◽

H Port ◽

K Gustav

Keyword(s):

Ir Spectroscopy ◽

Normal Mode ◽

Quantitative Evaluation ◽

Normal Mode Analysis ◽

Mode Analysis ◽

Quantum Yields

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HPLC in photokinetics: Determination of reaction mechanism and photochemical quantum yields of (E)-1-phenylpropene

Chromatographia ◽

10.1007/bf02311813 ◽

1987 ◽

Vol 23 (6) ◽

pp. 395-400 ◽

Cited By ~ 5

Author(s):

G. Gauglitz ◽

W. Schmid

Keyword(s):

Reaction Mechanism ◽

Quantum Yields

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Photocatalytic Activity: Experimental Features to Report in Heterogeneous Photocatalysis

Materials ◽

10.3390/ma11101990 ◽

2018 ◽

Vol 11 (10) ◽

pp. 1990 ◽

Cited By ~ 32

Author(s):

Md. Hoque ◽

Marcelo Guzman

Keyword(s):

Reaction Rate ◽

Monochromatic Light ◽

Heterogeneous Photocatalysis ◽

Research Articles ◽

Quantum Yields ◽

Characterization Methods ◽

Valuable Data ◽

Photocatalytic Activities ◽

Scientific Papers

Heterogeneous photocatalysis is a prominent area of research with major applications in solar energy conversion, air pollution mitigation, and removal of contaminants from water. A large number of scientific papers related to the photocatalysis field and its environmental applications are published in different journals specializing in materials and nanomaterials. However, many problems exist in the conception of papers by authors unfamiliar with standard characterization methods of photocatalysts as well as with the procedures needed to determine photocatalytic activities based on the determination of “apparent quantum efficiencies” within a wavelength interval or “apparent quantum yields” in the case of using monochromatic light. In this regard, an astonishing number of recent research articles include claims of highly efficient (photo)catalysts or similar terms about materials with superior or enhanced efficiency for a given reaction without proper experimental support. Consequently, the comparison of the efficiencies of photocatalysts may result as being meaningless, especially when reports are only based on expressions determining (1) a reaction rate per weight of catalyst or its surface area, (2) quantum efficiencies or quantum yields, and (3) turnover frequencies or turnover numbers. Herein, we summarize the standards needed for reporting valuable data in photocatalysis and highlight some common discrepancies found in the literature. This work should inform researchers interested in reporting photocatalysis projects about the correct procedures for collecting experimental data and properly characterizing the materials by providing examples and key supporting literature.

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