Self-assembled 3D porous flowerlike α-Fe2O3 hierarchical nanostructures: Synthesis, growth mechanism, and their application in photocatalysis

Abstract

In this work, a facile route using a simple solvothermal reaction to synthesize 3D porous flowerlike hierarchical nanostructures (HNs) of α-Fe(2)O(3) without employing templates or matrices for self-assembly is presented. The morphology and compositional characteristics of the 3D HNs were investigated by various techniques. The 3D HNs composed of 2D nanopetals, were intercrossed with each other and constructed from nanobricks with a length of about 100 nm and a diameter of about 30 nm. Influencing factors such as the reaction time, dosage of reactants and the solvents are systematically investigated. A possible formation mechanism for the 3D HNs is proposed. On the basis of characterization results, the growth of such 3D HNs has been proposed as a self-assembly followed by Ostwald ripening process. The specific surface area of the 3D HNs also was investigated by using nitrogen adsorption and desorption isotherms. The as-prepared α-Fe(2)O(3) HNs have a comparatively large Brunauer-Emmett-Teller (BET) surface area of about 52.51 m(2) g(-1). The photocatalytic properties of the as-obtained α-Fe(2)O(3) 3D HNs are systematically investigated, which was evaluated by the degradation of RhB dye under ultraviolet light irradiation. The result shows that photocatalytic activity is greatly affected by the hierarchical and porous structure.

Fabrication of 3D photocatalytic α-Fe2O3 structure using direct ink writing method

“…Second, it is reported that the efficiency of catalytic process depends on the adsorption and desorption of molecules on the surface of the catalyst. 18 of the catalyst can increase the photocatalytic reaction sites because of large relation area. As a result, the woodpile structure sample has a better degradation performance than that of the bulk material due to the fully developed inner space structure.…”

Visible photocatalytic degradation of Rhodamine B using Fe(III)-substituted phosphotungstic heteropolyanion

“…Zhou et al reported the synthesis of hematite (␣-Fe 2 O 3 ) nanocatalysts with welldefined architecture [28]. Zhu et al prepared 3D porous flowerlike hierarchical nanostructures of ␣-Fe 2 O 3 using an isopropyl alcoholmediated self-assembly solvothermal reaction [29]. In addition, Zhao et al succeeded in the fabrication of iron-modified rectorite bifunction material using ultrasonic-assisted ion-exchange and hydrolysis [30].…”

Surfactant-assisted growth and optical properties of ZnO hexagonal bilayer disk-like microstructures

“…Figure 1 On the basis of previous studies [3,[14][15][16][17][18][19][20][21][22][23] and the above results, the possible growth processes of the ZnO HBDMs can be schematically illustrated, as shown in figure 3. First, numerous ZnAc 2 was hydrolyzed in the highly basic reaction solution, and Zn(OH) 4 2− ions were first formed. Then, under solvothermal conditions, a large number of tiny ZnO nanoparticles spontaneously appeared from the dehydration of Zn(OH) 4 2− ions by initial homogeneous nucleation.…”

“…First, numerous ZnAc 2 was hydrolyzed in the highly basic reaction solution, and Zn(OH) 4 2− ions were first formed. Then, under solvothermal conditions, a large number of tiny ZnO nanoparticles spontaneously appeared from the dehydration of Zn(OH) 4 2− ions by initial homogeneous nucleation. The freshly crystalline nanoparticles are unstable and have a tendency to aggregate together and developed into larger crystals, which may be driven by the minimization of interfacial energy.…”

“…Considerable effort has been devoted to the morphology-controllable synthesis of ZnO [3]. In our previous works, we reported the control synthesis of semiconductor metal oxide using different methods [4][5][6][7][8][9][10][11][12]. One of the most promising methods is a biomimetic strategy that uses surfactants or polymers as the structuredirecting agent to control the nucleation, growth, and alignment of crystals [3].…”