Crystal‐Facet Engineering of Ferric Giniite by Using Ionic‐Liquid Precursors and Their Enhanced Photocatalytic Performances under Visible‐Light Irradiation

Abstract

In the work presented here, well-dispersed ferric giniite microcrystals with controlled sizes and shapes are solvothermally synthesized from ionic-liquid precursors by using 1-n-butyl-3-methylimidazolium dihydrogenphosphate ([Bmim][H2PO4]) as phosphate source. The success of this synthesis relies on the concentration and composition of the ionic-liquid precursors. By adjusting the molar ratios of Fe(NO3)3·9H2O to [Bmim][H2PO4] as well as the composition of ionic-liquid precursors, we obtained uniform microstructures such as bipyramids exposing {111} facets, plates exposing {001} facets, hollow spheres, tetragonal hexadecahedron exposing {441} and {111} facets, and truncated bipyamids with carved {001} facets. The crystalline structure of the ferric giniite microcrystals is disclosed by various characterization techniques. It was revealed that [Bmim][H2PO4] played an important role in stabilizing the {111} facets of ferric giniite crystals, leading to the different morphologies in the presence of ionic-liquid precursors with different compositions. Furthermore, since these ferric giniite crystals were characterized by different facets, they could serve as model Fenton-like catalysts to uncover the correlation between the surface and the catalytic performance for the photodegradation of organic dyes under visible-light irradiation. Our measurements indicate that the photocatalytic activity of as-prepared Fenton-like catalysts is highly dependent on the exposed facets, and the surface area has essentially no obvious effect on the photocatalytic degradation of organic dyes in the present study. It is highly expected that these findings are useful in understanding the photocatalytic activity of Fenton-like catalysts with different morphologies, and suggest a promising new strategy for crystal-facet engineering of photocatalysts for wastewater treatment based on heterogeneous Fenton-like process.

Controlled Synthesis of a Hexagonal‐Shaped NiO Nanocatalyst with Highly Reactive Facets {1 1 0} and Its Catalytic Activity

“…[1][2][3][4] The surface properties of nanocrystals highly depend on the shape of the materials with exposed facets, which have great influence on the activity of nanocrystals in the chemical reactions. [5][6][7] Thus, design and morphological control of the architecture of nanocrystals are very significant factors in nanoscience and nanotechnology owing to these unique size and shape-dependent phenomena. [8][9][10] The shape and facets of the nanocrystals can be finetuned with different chemical methods.…”

Ionic liquid-modulated preparation of hexagonal tungsten trioxide mesocrystals for lithium-ion batteries

“…Thus, the [Bmim] + ions can preferred to adsorb on the O 2--terminated {100} planes of h-WO 3 particles by electrostatic force. [45][46][47] More importantly, the hydrogen bond, can be induced to form between the hydrogen atom at the C2 position of the imidazole ring and the bridged oxygen atoms of {100} planes along [001] direction, as shown in Figure 2. As reported, [Bmim] + ions have very strong tendency to self-assemble into ordered structures stabilized by additional π-π interactions along the aligned hydrogen bonds.…”

Ionic Liquid Assisted Electrospinning of Porous LiFe0.4Mn0.6PO4/CNFs as Free‐Standing Cathodes with a Pseudocapacitive Contribution for High‐Performance Lithium‐Ion Batteries

“…A stable and spinnable precursor solution was first formulated by employing an IL, 1‐ n‐butyl ‐3‐methylimidazolium dihydrogenphosphate ([Bmim]H 2 PO 4 ), as phosphate source in the PAN‐based solution . In the subsequent electrospinning process (Figure S1), the anion of IL participated the formation of LFMP, the imidazole cation was in situ adsorbed on the formed nanoparticle surface due to electrostatic attraction, similar to the classic Dergaugin–Landau–Verwey–Overbeek (DLVO) type coulombic repulsion model (Figure a) .…”