Unprecedented Eighteen‐Faceted BiOCl with a Ternary Facet Junction Boosting Cascade Charge Flow and Photo‐redox

Exposure of anisotropic crystal facets allows the directional transfer of photoexcited electrons (e^?) and holes (h⁺), for spatial charge separation. High‐index facets with a high density of low‐coordinated atoms always serve as reactive catalytic sites. However, preparation of multi‐facets or high‐index facets is highly challenging for layered bismuth‐based photocatalysts. Herein, we report the preparation of unprecedented eighteen‐faceted BiOCl with {001} top facets and {102} and {112} oblique facets via a hydrothermal process. Compared to the conventional BiOCl square plates with {001} top facets and {110} lateral facets, the eighteen‐faceted BiOCl has highly enhanced photocatalytic activity for H₂ evolution and hydroxyl radicals (^.OH) production. Theoretical calculations and photodeposition results disclose that the of eighteen‐faceted BiOCl has a well‐matched {001}/{102}/{112} ternary facet junction, which provides a cascade path for more efficient charge flow than the binary facet junction in BiOCl square plates.     

The Effects of Exposed Specific Facets and Sulfation on the Surface Acidity of Cu2O Solids

Cuprous oxide microcrystals with {111}, {111}/{100}, and {100} exposed facets were synthesized. ³¹P MAS NMR using trimethylphosphine as the probe molecule was employed to study the acidic properties of samples. It was found that the total acidic density of samples increases evidently after sulfation compared with the pristine cuprous oxide microcrystals. During sulfation, new {100} facets are formed at the expense of {111} facets and lead to the generation of two Lewis acid sites due to the different binding states of SO₄²⁻ on {111} and {100} facets. Moreover, DFT calculation was used to illustrate the binding models of SO₄²⁻ on {111} and {100} facets. Also, a Pechmann condensation reaction was applied to study the acidic catalytic activity of these samples. It was found that the sulfated {111} facet has better activity due to its higher Lewis acid density compared with the sulfated {100} facet.     

Adsorption‐Induced Restructuring and Early Stages of Carbon‐Nanotube Growth on Ni Nanoparticles

Carbon adsorption on various Ni surfaces is investigated as a function of coverage via a combination of first‐principles simulations and field emission microscope experiments. It is found that carbon can be efficiently stored as subsurface carbides, but with different energetics on differently oriented surfaces depending on their compactness and density of adsorption sites. In the resulting morphological reshaping, {113} facets are predicted to grow at the expense of {111} and {100} facets, in excellent agreement with experimental observations. Moreover, at high coverage on the {113} surface the carbon adsorption energy passes through a maximum after which a structural crossover is realized such that carbon atoms tend to ascend to the surface to form one‐dimensional chains (which are the precursors of graphitic nanostructures). This rationalizes the experimental observation of an incubation time between carbon storage and the beginning of catalytic growth, and provides insight into the early stages (nucleation mechanism) of carbon nanotubes on Ni nanoparticles.     

The Origin of Shape Sensitivity in Palladium‐Catalyzed Suzuki–Miyaura Cross Coupling Reactions

The shape sensitivity of Pd catalysts in Suzuki–Miyaura coupling reactions is studied using nanocrystals enclosed by well‐defined surface facets. The catalytic performance of Pd nanocrystals with cubic, cuboctahedral and octahedral morphologies are compared. Superior catalytic reactivity is observed for Pd NCs with {100} surface facets compared to {111} facets. The origin of the enhanced reactivity associated with a cubic morphology is related to the leaching susceptibility of the nanocrystals. Molecular oxygen plays a key role in facilitating the leaching of Pd atoms from the surface of the nanocrystals. The interaction of O₂ with Pd is itself facet‐dependent, which in turn gives rise to more efficient leaching from {100} facets, compared to {111} facets under the reaction conditions.     

Electrospun Hierarchical LiV3O8 Nanofibers Assembled from Nanosheets with Exposed {100} Facets and their Enhanced Performance in Aqueous Lithium‐Ion Batteries

Hierarchical LiV₃O₈ nanofibers, assembled from nanosheets that have exposed {100} facets, have been fabricated by using electrospinning combined with calcination. The formation mechanism of hierarchical nanofibers was investigated by X‐ray diffraction and scanning electron microscopy. Poly(vinyl alcohol) (PVA) played a dual role in the formation of the nanofibers: besides acting as the template for forming the fibers, it effectively prevented the aggregation of LiV₃O₈ nanoparticles, thereby allowing them to grow into small nanosheets with exposed {100} facets owing to the self‐limitation property of LiV₃O₈. This nanostructure is beneficial for the insertion/extraction of lithium ions. Meanwhile, the {100} facets have fewer and smaller channels, which may effectively alleviate proton co‐intercalation into the electrode materials. Hence, the hierarchical LiV₃O₈ nanofibers exhibit higher discharge capacities and better cycling stabilities as the anode electrode material for aqueous lithium‐ion batteries than those reported previously. We demonstrate that these hierarchical nanofibers have promising potential applications in aqueous lithium‐ion batteries.     

Synthesis of {100} Facet Dominant Anatase TiO2 Nanobelts and the Origin of Facet‐Dependent Photoreactivity

Sword‐like anatase TiO₂ nanobelts exposed with 78 % clean {100} facets were synthesized and the facet‐dependent photoreactivity of anatase TiO₂ was investigated. By quantitative comparison with the reference {001} facets, the {100} facets possessed about ten‐times higher active sites density than that on {001} facets, resulting in higher photoreaction efficiency. After the active sites density normalization, the {100} and {001} facets exhibited distinct wavelength‐dependent photocatalytic performance, attributed to the anisotropic electronic structures in TiO₂ crystals.     

从头开始理解形貌依赖的CuOx-CeO2相互作用

CuOx/CeO2催化剂在CO氧化反应中表现出高催化活性和显著结构敏感性.文献报道中CuOx/CeO2催化剂体系的合成条件差异较大,从而导致观察到的CuOx-CeO2相互作用存在较大争议.因此,系统研究并阐明CuOx/CeO2催化剂中CuOx-CeO2相互作用对于理解复杂的CuOx-CeO2界面催化作用具有重要的研究意义.近期发现,氧化物纳米晶的形貌可作为一种新的结构参数,在不改变氧化物催化剂组成的条件下实现其结构和性能的调控.本文以不同形貌CeO2纳米晶为载体,包括优先暴露{110}+{100}晶面的CeO2纳米棒、优先暴露{100}晶面的CeO2纳米立方体和优先暴露{111}晶面的CeO2纳米多面体,采用等体积浸渍方法合成了Cu担载量为0.025%~5%的CuOx/CeO2纳米晶催化剂,结合谱学和电镜表征方法,以及CO吸附原位红外光谱,系统研究了CuOx物种在不同形貌CeO2纳米晶上的结构演化及其催化CO氧化的构-效关系.结构表征结果表明, CuOx物种结构不仅依赖于Cu的担载量,也依赖于载体CeO2的形貌.随着Cu担载量的增加, CuOx物种优先沉积在CeO2的表面缺陷位,然后聚集和长大;同时伴随着CuOx物种从孤立Cu离子到与载体强/弱相互作用的CuOx团簇,高分散Cu O颗粒和大尺寸Cu O颗粒.孤立Cu^+离子和与载体弱相互作用CuOx团簇主要形成于CeO2纳米立方体的表面,这可能与CeO2纳米立方体暴露的氧终止CeO2{100}晶面相关.CO吸附原位红外结果表明, CuOx团簇与不同CeO2表面相互作用的强度顺序为:CeO2纳米棒暴露的{110}面>CeO2纳米多面体暴露的{111}面>CeO2纳米立方体暴露的{100}面.CeO2纳米立方体与Cu2+离子间相互作用弱于与Cu^+之间的,因此CeO2纳米立方体负载的CuOx物种在CO还原过程中容易停留在稳定的Cu^+中间物种;而CeO2纳米棒与Cu2+离子之间的相互作用强于与Cu^+之间的相互作用,因此CeO2纳米棒负载的CuOx物种在CO还原过程中容易形成金属铜.因此CO吸附原位红外光谱观察到CeO2纳米立方体负载CuOx催化剂中吸附在Cu^+的CO物种远远多于CeO2纳米棒负载CuOx催化剂.CO氧化反应结果表明, CuOx/CeO2催化剂表现出同时依赖于CuOx物种结构和CeO2形貌的结构敏感性.CuOx/CeO2催化剂活性表现出与CuOx/CeO2催化剂的CO还原性能的正相关性,说明中CuOx/CeO2催化CO氧化反应遵循Mv K反应机理.这些结果系统地关联了CeO2形貌, CuOx-CeO2相互作用, CuOx物种结构和CeO2还原性能, CuOx/CeO2催化CO氧化反应活性.     

Platinum Multicubes Prepared by Ni2+‐Mediated Shape Evolution Exhibit High Electrocatalytic Activity for Oxygen Reduction

Pt(100) facets are generally considered less active for the oxygen reduction reaction (ORR). Reported herein is a unique Pt‐branched structure, a multicube, whose surface is mostly enclosed by {100} facets but contains high‐index facets at the small junction area between the adjacent cubic components. The synthesis is accomplished by a Ni²⁺‐mediated facet evolution from high‐index {311} to {100} facets on the frameworks of multipods. Despite the high {100} facet coverage, the Pt multicubes exhibit impressive ORR activity in terms of half‐wave potential and current density nearly to the level of the most active Pt‐based catalysts, while the durability of catalysts is well retained. The facet evolution creates a set of samples with tunable ratios of high‐index to low‐index facets. The results reveal that the excellent ORR performance of Pt multicubes is a combined result of active sites by high‐index facets and low resistance by flat surface. It is anticipated that this work will offer a new approach to facet‐controlled synthesis and ORR catalysts design.     

Controlled Synthesis and Enhanced Catalytic and Gas‐Sensing Properties of Tin Dioxide Nanoparticles with Exposed High‐Energy Facets

A morphology evolution of SnO₂ nanoparticles from low‐energy facets (i.e., {101} and {110}) to high‐energy facets (i.e., {111}) was achieved in a basic environment. In the proposed synthetic method, octahedral SnO₂ nanoparticles enclosed by high‐energy {111} facets were successfully synthesized for the first time, and tetramethylammonium hydroxide was found to be crucial for the control of exposed facets. Furthermore, our experiments demonstrated that the SnO₂ nanoparticles with exposed high‐energy facets, such as {221} or {111}, exhibited enhanced catalytic activity for the oxidation of CO and enhanced gas‐sensing properties due to their high chemical activity, which results from unsaturated coordination of surface atoms, superior to that of low‐energy facets. These results effectively demonstrate the significance of research into improving the physical and chemical properties of materials by tailoring exposed facets of nanomaterials.     

Axis‐Oriented,Continuous Anatase Titania Films with Exposed Reactive {100} Facets

Homogeneous TiO₂ single crystals with high exposure of {100} reactive facets were constructed as a seed monolayer on transparent conductive substrates with the desired orientation of reactive facets. A secondary growth process was subsequently carried out on the monolayer seed film to form an axis‐oriented continuous reactive film. Performing secondary growth with different precursors led to optimized conditions for high‐performance photoelectrochemical activity of anatase TiO₂ films. Experimental techniques such as UV/Vis absorption spectroscopy, X‐ray diffraction, high‐resolution SEM, and photoelectrochemistry were used to characterize the structural, optical, and photoelectrochemical properties of the as‐synthesized films. As a photoanode in a photoelectrochemical cell, the axis‐oriented reactive film shows a maximum photocurrent density of 0.3 mA cm^?2, as opposed to 0.075 mA cm^?2 for non‐axis‐oriented (randomly oriented) TiO₂ film.     

Atomic‐Scale Determination of Active Facets on the MoVTeNb Oxide M1 Phase and Their Intrinsic Catalytic Activity for Ethane Oxidative Dehydrogenation

Aberration‐corrected high‐angle annular dark‐field scanning transmission electron microscopy (HAADF‐STEM) has been used to image the basal {001} plane of the catalytically relevant M1 phase in MoVTeNb complex oxides. Facets {010}, {120}, and {210} are identified as the most frequent lateral termination planes of the crystals. Combination of STEM with He ion microscopy (HIM) images, Rietveld analysis, and kinetic tests reveals that the activation of ethane is correlated to the availability of facets {001}, {120}, and {210} at the surface of M1 crystals. The lateral facets {120} and {210} expose crystalline positions related to the typical active centers described for propane oxidation. Conversely, the low activity of the facet {010} is attributed to its configuration, consisting of only stable M₆O₂₁ units connected by a single octahedron. Thus, we quantitatively demonstrated that differences in catalytic activity among M1 samples of equal chemical composition depend primarily on the morphology of the particles, which determines the predominant terminating facets.     

Synthesis and mechanistic study of palladium nanobars and nanorods

This paper describes a simple and versatile method for growing highly anisotropic nanostructures of Pd, single-crystal nanobars bounded by {100} facets and single-crystal nanorods with their side surfaces enclosed by {100} and {110} facets. According to thermodynamic arguments, Pd atoms should nucleate and grow in a solution phase to form cuboctahedrons of spherical shape with their surfaces bounded by a mix of {111} and {100} facets. Anisotropic nanostructures can only form under kinetically controlled conditions, while the cubic symmetry is broken. In the present system, we found that one-dimensional growth could be induced and maintained through an interplay of the following processes: (i) speedy reduction of the precursor to ensure prompt addition of atoms to the seed; (ii) chemisorption of bromide on the seed to promote the formation of {100} and {110} facets; and (iii) localized oxidative etching on one specific face of the seed to initiate preferential growth on this face. Experimentally, the anisotropic growth can be achieved by varying the type and concentration of reducing agent, as well as by adjusting the reaction temperature. This methodology developed for Pd has also been extended to both Au and Pt. As expected for a kinetically controlled product, the anisotropic nanostructure evolved into the thermodynamically favored shape during an aging process.     

纳米Pd的形貌和尺寸可控制备及其1,4-丁炔二醇加氢性能

采用化学还原法合成Pd纳米立方体,并将其作为晶种,进一步合成大尺寸的纳米Pd立方体以及具有不同{100}和{111}晶面比例的纳米Pd多面体.将形貌和尺寸可控的纳米Pd溶胶应用于1,4-丁炔二醇催化加氢的反应中,反应结果表明,纳米Pd的催化性能取决于其尺寸和形貌.{111}晶面的催化活性高于{100}晶面,PVP稳定的Pd胶体对1,4-丁烯二醇均具有较高选择性,具有适当{100}和{111}晶面比例的纳米Pd多面体对1,4-丁烯二醇的选择性可达96%.     

Selective Growth and Structural Analysis of Regular MnO Nanooctapods Bearing Multiple High‐Index Surface Facets

Although numerous morphologies of MnO nanostructures have been reported, an exact structural analysis and mechanistic study has been lacking. In the present study, the formation of regular MnO octapods was demonstrated in a simple procedure, comprising the thermal decomposition of manganese oleate. Because of their structural uniformity, an ideal three‐dimensional model was successfully constructed. The eight arms protruded from the cubic center with tip angles of 38° and surface facets of {311} and {533} with rounded edges. The concentrations of oleate and chloride ions were the determining factors for the octapod formation. Selective coordination of the oleate ions to the {100} faces led to edge growth along the <111> direction, which was then limited by the chloride ions bound to the high‐index surface facets. These structural and mechanistic analyses should be helpful for understanding the complex nanostructures and for tuning their structure‐related properties.     

A 3D AgCl Hierarchical Superstructure Synthesized by a Wet Chemical Oxidation Method

A novel 3D AgCl hierarchical superstructure, with fast growth along the 〈111〉 directions of cubic seeds, is synthesized by using a wet chemical oxidation method. The morphological structures and the growth process are investigated by scanning electron microscopy and X‐ray diffraction. The crystal structures are analyzed by their crystallographic orientations. The surface energy of AgCl facets {100}, {110}, and {111} with absorbance of Cl^? ions is studied by density functional theory calculations. Based on the experimental and computational results, a plausible mechanism is proposed to illustrate the formation of the 3D AgCl hierarchical superstructures. With more active sites, the photocatalytic activity of the 3D AgCl hierarchical superstructures is better than those of concave and cubic ones in oxygen evolution under irradiation by visible light.     

Diffusion processes and growth on aluminum cluster surfaces

Diffusion processes of adatoms on icosahedral and Wulff polyhedral aluminum cluster surfaces have been studied by molecular dynamics simulations using the effective medium theory. Activation energies of diffusion mechanisms along {111} and {100} facets and from one facet to another, including different hopping and exchange processes as well as more exotic events, have been calculated. Exchange diffusion of an adatom by a chain mechanism through a {100} facet between two {111} facets and hopping diffusion across the edge between two {111} facets via a pull of another adatom on the neighbour facet are shown to play an important role. Adatoms on {111} facets are mobile already at very low temperatures, but on {100} facets diffusion starts above the room temperature as well as diffusion from {111} facets to {100} facets. Diffusion from {100} facet to other facets was not observed until at temperatures close to the melting temperatures of clusters. Dynamical simulations at different temperatures confirmed the appearance of diffusion mechanisms predicted by the activation energies.     

Morphology‐Engineered Highly Active and Stable Ru/TiO2 Catalysts for Selective CO Methanation

Ru/TiO₂ catalysts exhibit an exceptionally high activity in the selective methanation of CO in CO₂‐ and H₂‐rich reformates, but suffer from continuous deactivation during reaction. This limitation can be overcome through the fabrication of highly active and non‐deactivating Ru/TiO₂ catalysts by engineering the morphology of the TiO₂ support. Using anatase TiO₂ nanocrystals with mainly {001}, {100}, or {101} facets exposed, we show that after an initial activation period Ru/TiO₂‐{100} and Ru/TiO₂‐{101} are very stable, while Ru/TiO₂‐{001} deactivates continuously. Employing different operando/in situ spectroscopies and ex situ characterizations, we show that differences in the catalytic stability are related to differences in the metal–support interactions (MSIs). The stronger MSIs on the defect‐rich TiO₂‐{100} and TiO₂‐{101} supports stabilize flat Ru nanoparticles, while on TiO₂‐{001} hemispherical particles develop. The former MSIs also lead to electronic modifications of Ru surface atoms, reflected by the stronger bonding of adsorbed CO on those catalysts than on Ru/TiO₂‐{001}.     

Oxidation‐induced nanostructures on Cu{100}, Cu(Ag) and Ag/Cu{100} studied by photoelectron spectroscopy

Initial surface oxidation and nanoscale morphology on Cu{100}, Cu(Ag) and Ag/Cu{100} have been investigated in situ by X‐ray photoelectron spectroscopy (XPS), X‐ray induced Auger electron spectroscopy (XAES) and the inelastic electron background analysis as a function of oxygen exposure at 3.7 × 10^?2 and 213 mbar pressures at a surface temperature of 373 K. Relative Cu₂O concentrations have been quantified by analysis of the peak shape of the XAES Cu LMM transition. The surface morphology of Cu₂O islands and the Ag layer has been characterized by inelastic electron background analysis of XAES O KLL and Ag 3d transitions. Oxygen‐induced segregation of Cu, as well as the subsequent Cu₂O island formation on Cu(Ag) and Ag/Cu{100} surfaces, has been investigated quantitatively. Our results indicate that Ag has a clear inhibitive effect on the initial oxidation and Cu₂O island formation on Cu(Ag) and Ag/Cu{100} surfaces. The Cu₂O islands are also observed to remain highly strained on Ag/Cu{100} even at higher O₂ exposures. The results suggest that strained Cu₂O islands eventually penetrate through the buried Ag layer, and in conjunction with segregating Cu atoms enable the oxidation to proceed at a similar rate to or even faster than on the unalloyed Cu surface. Copyright © 2007 John Wiley & Sons, Ltd.     

具有丰富介孔Cu-SAPO-34催化剂制备及其低温氨气选择性催化还原反应(英文)

氮氧化物(NO_x)是主要的大气污染物之一,与光化学烟雾、全球气候变暖等环境问题密切相关.随着汽车产业的高速发展,柴油车排放尾气中的NOx脱除成为国内外尾气催化净化领域最突出的难点之一.其中氨气选择性催化还原技术(NH_3-SCR)由于其高效率、低成本的特征已成为主要的移动源脱硝技术.目前,实际应用中最广泛的是V_2O_5-WO_3(MoO_3)/TiO_2催化剂,然而一些不可避免的因素仍然存在,比如V具有较强的毒性,较高的操作温度,较窄的活性温度窗口以及易将SO_2氧化为SO_3导致催化剂表面会有大量的硫酸盐沉积而失活等.因此很有必要开发一种无钒SCR催化剂.近年来,分子筛负载过渡金属作为催化剂引起了研究者的广泛兴趣,其中Cu-CHA分子筛催化剂因其高SCR活性,高N2选择性,较宽的温度窗口以及优异的稳定性引起研究者的广泛关注.就Cu/SAPO-34而言,传统的制备方法是利用离子交换法将Cu离子引入到SAPO-34微孔孔道中,然而由于微孔会限制Cu离子的分布,导致绝大多数Cu优先分布在分子筛外表面,从而限制了其活性发挥.Martínez-Franco课题组利用双模板一步法成功制备了Cu-SAPO-34催化剂,提高了分子筛中活性Cu离子数目.Peden课题组发现在NOx的NH_3-SCR反应中Cu-SAPO-34催化剂存在低温动力学限制.因此开发一种具有丰富介孔的多级孔Cu-SAPO-34催化剂势在必行.我们利用一步水热晶化法成功制备了一系列具有丰富介孔的Cu-SAPO-34催化剂.采用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、氮气吸附-脱附、X射线衍射(XRD)、~(27)Al核磁共振(Al-NMR)、紫外可见漫反射光谱(UV-Vis DRS)、电感耦合等离子体-原子发射光谱(ICP-AES)、X射线光电子能谱(XPS)、氢气程序升温还原(H2-TPR)和电子顺磁共振(EPR)等表征手段研究了Cu-SAPO-34多级孔催化剂的物理化学性质.XRD测试结果证实,H-Cu-SAPO-34催化剂具有典型的CHA结构.TEM和N2吸附-脱附测试结果表明,H-Cu-SAPO-34催化剂具有丰富的介孔结构.Al-NMR测试结果表明,多种配位的Al物种存在于H-Cu-SAPO-34中.UV-Vis DRS测试结果证实了孤立Cu~(2+)和高分散的CuO的存在,没有观察到(Cu-O-Cu)2+和CuAl2O4物种的存在.ICP-AES和XPS测试结果表明,H-Cu-SAPO-34催化剂具有相似的Cu含量,并且H-Cu-SAPO-34-20催化剂具有最高的Cu~(2+)含量.H2-TPR测试结果表明,H-Cu-SAPO-34-20催化剂具有最低的孤立Cu~(2+)还原温度以及最高的孤立Cu~(2+)含量.这可能有利于其NH3-SCR活性提高.同时H2-TPR还表明,H-Cu-SAPO-34催化剂中存在含量不等的孤立Cu+,并且孤立Cu~(2+)是NH3-SCR反应的主要活性中心.EPR测试结果进一步表明,位于SAPO-34椭球腔内(Site(I))的孤立Cu~(2+)是该反应的主要活性位.由NO的NH3-SCR反应测试结果来看,相比于普通的Cu/SAPO-34催化剂,具有丰富介孔结构的H-Cu-SAPO-34催化剂呈现出更高的低温催化活性,同时H-Cu-SAPO-34-20催化剂具有最高的低温NH3-SCR催化活性,这与其较高的活性Cu~(2+)含量以及较低的孤立Cu~(2+)还原温度密切相关.动力学测试结果表明,所合成的H-Cu-SAPO-34多级孔催化剂具有相似的活化能(Ea=98 kJ/mol),并且该值远大于普通CHA基SCR催化剂,这意味着介孔的存在确实大大降低了反应物分子在H-Cu-SAPO-34孔道内的扩散阻力,提高了反应物分子与活性位的接触概率,从而提高了其低温NH3-SCR催化性能.     

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

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.