1. New insights into the mechanism of photocatalytic hydrogen evolution from aqueous solutions of saccharides over CdS-based photocatalysts under visible light.
- Author
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Kurenkova, Anna Yu., Markovskaya, Dina V., Gerasimov, Evgeny Yu., Prosvirin, Igor P., Cherepanova, Svetlana V., and Kozlova, Ekaterina A.
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HYDROGEN evolution reactions , *PHOTOCATALYSTS , *SACCHARIDES , *VISIBLE spectra , *AQUEOUS solutions , *HYDROGEN , *QUANTUM efficiency , *ELECTROLYTIC cells - Abstract
A new multiphase photocatalyst – 1%Pt/Cd 0.6 Zn 0.4 S/Cd 0.1 Zn 0.9 S – was synthesized by a simple hydrothermal treatment of as-prepared Cd 0.3 Zn 0.7 S solid solution and thoroughly characterized by different methods. The activity was tested in a sustainable process of hydrogen evolution from aqueous solutions of two saccharides (glucose and xylose) under visible light. The mechanism of the photocatalytic hydrogen evolution from complex organic substrates is still controversial. In this research it was shown that optimizing the experimental conditions (pH, substrate concentration) leads to a significant increase in the photocatalytic activity for both saccharides. A kinetic equation based on a Langmuir model and including the degree of dissociation of the substrate was proposed and verified for the first time. The highest activities during hydrogen evolution for glucose and xylose were achieved in strongly alkaline media. The photocatalyst 1%Pt/CdZnS120 possessed an activity equal to 3.4 mmol H 2 h−1 g−1 (glucose, apparent quantum efficiency 8.4%), that exceeds recently reported values. Image 1 • New photocatalyst 1%Pt/Cd 0.6 Zn 0.4 S/Cd 0.1 Zn 0.9 S was synthesized and characterized. • Activity was tested in H 2 evolution from solutions of glucose and xylose (450 nm). • The highest activity for glucose solution was 3.4 mmol H 2 h-1 g-1 with AQE = 8.4%. • High stability of the proposed photocatalyst at a high pH (5 M NaOH) was confirmed. • Kinetic equation based on a Langmuir model was proposed for both saccharides. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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