Development ofα-Fe₂O₃/Nb₂O₅photocatalysts by a Pechini sol–gel route: structural, morphological and optical influence

Synthesis, characterization and evaluation of iron oxides and niobium in the removal of dyes in Fenton type reactions and photocatalysis

“…However, •OH radicals have greater oxidative potential, so they are more effective in the system [27,28]. Materials bandgap values (Table 1) suggest that all solids have semiconductors electronic properties [29][30][31].The solids showed practically the same result (1.8 eV) and sample FeNb1.5 favored a little more the reduction of the prohibited band (1.7 eV), demonstrating that this ratio can potentiate photocatalytic reactions even more [32].This factor generates advantages in the use of mixed oxides based on iron and niobium, since pure niobium oxide absorbs light in the ultraviolet region (bandgap from 3.1 to 4.0 eV) and mixed oxides have spectral photosensitivity in the visible range, being possible to use sunlight as energy source [30,33,34].…”

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“…Several synthesis methodologies have already been used to produce ferrites including co-precipitation [14,32], proteic sol-gel [10], hydrothermal [33][34][35], solvothermal [36][37][38], conventional sol-gel [29], combustion [39], solid state reaction [40], solution blow spinning [16], and complexation [41]. The sol-gel process is one of the most accepted methods for producing ferrites where chelates are formed through a complexation reaction between multivalent ions and citric acid, a multidentate ligand [30,42]. However, the possibility of using transition metals with different oxidation states to produce a wide variety of ceramic materials requires a versatile complexing agent such as ethylenediamine tetra-acetic acid (EDTA).…”

“…EDTA can be combined with metal ions in the proportion 1:1, regardless of the cation charge, the exception standing for alkali metals that do not chelate with EDTA. This molecule has six donor groups of electron pairs for bonds with metal ions, EDTA has four carboxylic groups and two amino groups, thus, it is classified as a hexadentate ligand [42].…”

Synthesis of Hematite Nanodiscs from Natural Laterites and Investigating Their Adsorption Capability of Removing Ni2+ and Cd2+ Ions from Aqueous Solutions

“…Although there is a high potential of laterites to be used in synthesizing value-added iron-based nanomaterials, limited work has been conducted so far. Commonly studied iron-based nanomaterials include magnetite (Fe 3 O 4 ) [29], goethite(α-FeOOH) [30], and hematite(Fe 2 O 3 ) [31][32][33]. Among those, hematite nanoparticles have been investigated for a range of applications, including adsorption [18,[34][35][36][37], water splitting [38,39], photochemical [40,41], catalytic [40,42], and electrochemical [43,44] processes.…”