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Title: Microwave-assisted synthesis of Ca1-xMnxMoO4 (x = 0, 0.2, 0.7, and 1) and its application in artificial photosynthesis.
Authors: Silva Junior, Roberto Carlos da
Nogueira, André Esteves
Giroto, Amanda Soares
Torres, Juliana Arriel
Siqueira, Kisla Prislen Félix
Keywords: Artificial photosynthesis
Issue Date: 2021
Citation: SILVA JÚNIOR, R. C. da et al. Microwave-assisted synthesis of Ca1-xMnxMoO4 (x = 0, 0.2, 0.7, and 1) and its application in artificial photosynthesis. Ceramics International, v. 47, p. 5388-5398, 2021. Disponível em: <>. Acesso em: 10 jun. 2021.
Abstract: This work reports, for the first time, to the best of our knowledge, the use of calcium molybdates doped with Mn2+ in the catalytic photoreduction of CO2 to produce compounds with higher added value that have appli cations in different branches of the chemical industry. The molybdates were prepared at 100 ◦C by microwave assisted hydrothermal synthesis and were characterized by X-ray diffraction, Raman vibrational spectroscopy, scanning electron microscopy, and diffuse UV–vis reflectance spectroscopy. The synthesized Ca1-xMnxMoO4 catalysts (x = 0, 0.2, 0.7, and 1) were also calcined at 500 ◦C, in order to investigate possible phase transitions. For x = 0 and 0.2, the samples crystallized in the tetragonal structure (I41/a, #88) and no phase transitions were observed at 500 ◦C. For x = 0.7 and 1.0, the phase produced at 100 ◦C was a hydrated form of manganese molybdate that exhibited triclinic structure (P1, #2) and became monoclinic (C2/m, #12) when calcined at 500 ◦C. The catalysts subsequently investigated were the pure molybdate and the materials with doping contents of 20 and 70 mol% Mn2+, hydrothermally treated at 100 ◦C and after calcination at 500 ◦C. The band gap en ergies ranged from 2.77 to 3.50 eV. In the performance tests, the productions of CO and CH4 after 6 h of irra diation were in the ranges 2.41–19.74 and 0.21–0.82 μmol g− 1 , respectively. The doped x = 0.2 sample treated at 100 ◦C exhibited the best performance, producing the highest amounts of CO and CH4. The results indicated that the doping of CaMoO4 with Mn2+ improved the performance of this ceramic for the purpose of artificial photosynthesis. Furthermore, our results support a deep discussion about the role of doping content and crys talline structure of the molybdates on the photocatalytic activity.
ISSN: 0272-8842
Appears in Collections:DEQUI - Artigos publicados em periódicos

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