Green synthesis of earth-abundant metal sulfides (FeS2, CuS, and NiS2) and their use as visible-light active photocatalysts for H2 generation and dye removal

• Published in: Journal of materials science. Materials in electronics Vol. 29; no. 13; pp. 11613 - 11626
• Main Authors: Huerta-Flores, Ali M., Torres-Martínez, Leticia M., Moctezuma, Edgar, Singh, Aadesh P., Wickman, Björn
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-07-2018; Springer Nature B.V
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Copper sulfides; Earth; Ethanol; Ethylenediaminetetraacetic acids; Hydrogen; Hydrogen evolution reactions; Hydrogen production; Indigo; Materials Science; Metal sulfides; Optical and Electronic Materials; Optical properties; Oxidation; Particle size; Phenols; Photocatalysis; Photocatalysts; Photodegradation; Pyrite; Radiation; Reagents; Semiconductors; Sodium sulfide; Sodium sulfite
• ISSN: 0957-4522; 1573-482X; 1573-482X
• DOI: 10.1007/s10854-018-9259-x

Earth-abundant metal sulfides (for example, FeS
2
, CuS, and NiS
2
) are promising materials to be used as photocatalysts due to their suitable electronic and optical properties. In this work, we present a fast and low-cost hydrothermal method to synthesize these materials. They are integrally characterized and evaluated as photocatalysts for the H
2
evolution reaction and the degradation of indigo carmine (IC). FeS
2
exhibits the highest photocatalytic efficiency (32 µmol g
−1
 h
−1
of H
2
evolution and 88% of indigo carmine degradation) under visible light, and this activity is attributed to a larger crystallite size, smaller particle size, and lower recombination, compared to CuS and NiS
2
. Moreover, three different sacrificial reagents are studied for the H
2
evolution reaction, including Na
2
S/Na
2
SO
3
, EDTA, and ethanol. Na
2
S/Na
2
SO
3
shows the highest enhancement in the activity, increasing the rate of H
2
production more than 15 times. This behavior is related to the lower oxidation potential of Na
2
S/Na
2
SO
3
. Moreover, we evaluate the activity of the materials for the electrochemical hydrogen evolution reaction (HER). In summary, this work provides valuable information for effective applications of these earth-abundant metal sulfides for energy and environmental photocatalytic processes.