Synthesis and Characterization of Cerium Molybdate Semiconductor Nanoparticles

Abstract

Cerium molybdate semiconductive nanoparticles were synthesized by the EDTA-citrate combined complexation method. Gel thermal degradation behavior, phase formation, morphology, composition and band gap of cerium molybdate powders were characterized by TG/DSC, XRD, SEM/EDS and DRS analysis, respectively. The nanoparticles were synthesized by fixing the pH of the reaction medium to 9, producing an organometallic gel which was heated to 230 ºC obtaining a precursor powder. The precursors were calcined in a temperature range of 450 -800 ºC for 3 h. The cerium molybdate powders were characterized and the phase evolution, morphology and band gap changes with the increase of calcining temperature were investigated. It was observed that the calcining temperature directly influences the formation of the crystalline structure, appearance of other phases in the materials and the particle size.

Evaluation of two processing routes for the synthesis of molybdenum oxide with cobalt addition

“…The data are presented in Table V. where k is the absorption constant, which is dependent on the material, and n can assume values of 1/2, 3/2, 2 and 3 according to the electronic transition (directly allowed, indirectly allowed, directly prohibited or indirectly prohibited, respectively) that occurs; n was taken to be ½ according to [20]. Direct transition is often used to describe crystalline MoO 3 films, with reported optical band gaps in the range of 2.8 to 3.5 eV [21,22].…”

Synthesis of NiMoO4 by the Complexation Method Combining EDTA-Citrate and its Behavior Against Biodiesel Acidity

“…This loss of mass is explained by the synthetic route herein used, which uses starting reagents that undergo complete combustion during the calcination process, eliminating all organic components. The synthetic approach used in this study allows to obtain high-crystallinity ceramic materials with good chemical homogeneity and free of secondary phases using a low processing time that saves energy [48][49][50][51] .…”

“…Concerning the synthesis of metal molybdates, sol-gel 33,34 , solvothermal 35 and precipitation methods have been widely used [36][37][38][39][40][41][42] . The complexation method combining EDTA-Citrate has stood out in recent years for synthesizingdifferent materials such as perovskites (ABO 3 ) 29,43,44 , fluorites (A 2 X 3 , A 2 B 2 X 7 ) 45,46 , ferrites (ABC 2 X 5 ) 47 , and tungstates/molybdates (AWO 4 /AMoO 4 ) [48][49][50] . In general, it is a simple synthetic method that presents easy reproducibility and short synthesis time as advantages over other methods 43,[45][46][47][48] .…”

“…In general, it is a simple synthetic method that presents easy reproducibility and short synthesis time as advantages over other methods 43,[45][46][47][48] . The possibility of manipulating synthesis parameters, such as pH, time and calcination temperatureallows to change/modify the material properties 19,47,[49][50][51] .…”

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“…Citric acid acts as an auxiliary complexing agent in this synthesis process [44]. This methodology allows adjusting parameters such as heating time, heating rate, calcination temperature, initial pH of the synthesis, and the stoichiometric ratio chelating/cations, thus reaching nanoparticles with different morphologies, high purity, high degree of crystallinity and precise stoichiometric control [45][46][47][48]. In this synthesis process, the ions in solution are organized at an atomic level within an organic matrix formed by complexing agents [49].…”