Microemulsion synthesis, characterization of highly visible light responsive rare Earth-doped bi(2) o(3)

In this paper, Bi₂O₃ and rare earth (La, Ce)‐doped Bi₂O₃ visible‐light‐driven photocatalysts were prepared in a Triton X‐100/n‐hexanol/cyclohexane/water reverse microemulsion. The resulting materials were characterized by X‐ray powder diffraction (XRD), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) surface area, photoluminescence spectra (PLS) and UV–Vis diffuse reflectance spectroscopy. The XRD patterns of the as‐prepared catalysts calcined at 500°C exhibited only the characteristic peaks of monoclinic α‐Bi₂O₃. PLS analysis implied that the separation efficiency for electron‐hole has been enhanced when Bi₂O₃ was doped with rare earth. UV–Vis diffuse reflectance spectroscopy measurements presented an extension of light absorption into the visible region. The photocatalytic activity of the samples was evaluated by degradation of methyl orange (MO) and 2,4‐dichlorophenol (2,4‐DCP). The results displayed that the photocatalytic activity of rare earth‐doped Bi₂O₃ was higher than that of dopant‐free Bi₂O₃. The optimal dopant amount of La or Ce was 1.0 mol%. And the mechanisms of influence on the photocatalytic activity of the catalysts were discussed.     

Template‐Free Fabrication of Bi2O3 and (BiO)2CO3 Nanotubes and Their Application in Water Treatment

Uniform bismuth oxide (Bi₂O₃) and bismuth subcarbonate ((BiO)₂CO₃) nanotubes were successfully synthesized by a facile solvothermal method without the need for any surfactants or templates. The synergistic effect of ethylene glycol (EG) and urea played a critical role in the formation of the tubular nanostructures. These Bi₂O₃ and (BiO)₂CO₃ nanotubes exhibited excellent Cr^VI‐removal capacity. Bi₂O₃ nanotubes, with a maximum Cr^VI‐removal capacity of 79 mg g^?1, possessed high removal ability in a wide range of pH values (3–11). Moreover, Bi₂O₃ and (BiO)₂CO₃ nanotubes also displayed highly efficient photocatalytic activity for the degradation of RhB under visible‐light irradiation. This work not only demonstrates a new and facile route for the fabrication of Bi₂O₃ and (BiO)₂CO₃ nanotubes, but also provides new promising adsorbents for the removal of heavy‐metal ions and potential photocatalysts for environmental remediation.     

Samarium and Nitrogen Co‐Doped Bi2WO6 Photocatalysts: Synergistic Effect of Sm3+/Sm2+ Redox Centers and N‐Doped Level for Enhancing Visible‐Light Photocatalytic Activity

Samarium and nitrogen co‐doped Bi₂WO₆ nanosheets were successfully synthesized by using a hydrothermal method. The crystal structures, morphology, elemental compositions, and optical properties of the prepared samples were investigated. The incorporation of samarium and nitrogen ions into Bi₂WO₆ was proved by X‐ray diffraction, energy dispersive X‐ray spectroscopy, and X‐ray photoelectron spectroscopy. UV/Vis diffuse reflectance spectroscopy indicated that the samarium and nitrogen co‐doped Bi₂WO₆ possessed strong visible‐light absorption. Remarkably, the samarium and nitrogen co‐doped Bi₂WO₆ exhibited higher photocatalytic activity than single‐doped and pure Bi₂WO₆ under visible‐light irradiation. Radical trapping experiments indicated that holes (h⁺) and superoxide radicals ( ^. O₂^?) were the main active species. The results of photoluminescence spectroscopy and photocurrent measurements demonstrated that the recombination rate of the photogenerated electrons and holes pairs was greatly depressed. The enhanced activity was attributed to the synergistic effect of the in‐built Sm³⁺/Sm²⁺ redox pair centers and the N‐doped level. The mechanism of the excellent photocatalytic activity of Sm‐N‐Bi₂WO₆ is also discussed.     

Thermal Stability,Microstructure and Photocatalytic Activity of the Bismuth Oxybromide Photocatalyst

Flake BiOBr was first prepared by a solution method at room temperature. Then, the produced BiOBr was calcined at different temperatures. It was found that BiOBr is not a stable compound. It transforms to plate‐like Bi₂₄O₃₁Br₁₁at around 750°C and the formed Bi₂₄O₃₁Br₁₁ can further convert to rod‐like α‐Bi₂O₃ at around 850°C. The prepared compounds were characterized with X‐ray diffraction (XRD), N₂ physical adsorption, scanning electron microscopy (SEM), and UV‐Vis diffuse reflectance spectra (DRS), respectively. The photocatalytic activity of the produced bismuth oxybromides was evaluated by photocatalytic decomposition of acid orange II under both visible light (λ>420 nm) and UV light (λ=365 nm) irradiation. Results show that these compounds have different band gaps and different photocatalytic properties. The band gap energies of the as‐prepared samples were found to be 2.82, 2.79, 2.60 and 3.15 eV for BiOBr, BiOBr/Bi₂₄O₃₁Br, Bi₂₄O₃₁Br, and α‐Bi₂O₃, respectively. Under both UV light and visible light irradiation, the photocatalytic activity follows the order: BiOBr/Bi₂₄O₃₁Br mixture>BiOBr>Bi₂₄O₃₁Br>α‐Bi₂O₃. The change in photocatalytic activity could be attributed to the different light absorption ability and microstructures of the photocatalysts.     

Enhanced visible‐light‐driven photocatalytic activity of F doped reduced graphene oxide ‐ Bi2WO6 photocatalyst

The reduced graphene oxide‐Bi₂WO₆ (rGO‐BWO) photocatalysts with the different R_F/O values (molar ratio of the F molar mass and the O's molar mass of Bi₂WO₆) had been successfully synthesized via one‐step hydrothermal method. The F‐doped rGO‐BWO samples were characterized by X‐ray diffraction patterns (XRD), field‐emission scanning electron microscopy (FE‐ESEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller surface area (BET), X‐ray photoelectron spectroscopy (XPS) and UV–vis diffuse reflectance spectra (DRS). The results indicate that F^? ions had been successfully doped into rGO‐BWO samples. With the increasing of the R_F/O values from 0 to 2%, the evident change of the morphology and the absorption edges of F‐doped rGO‐BWO samples and the photocatalytic activities had been enhanced. Moreover, the photocatalytic activity of F‐doped rGO‐BWO with R_F/O = 0.05 were better than rGO‐BWO and the other F‐doped rGO‐BWO under 500 W Xe lamp light irradiation. The enhanced photocatalytic activity can be attributed to the morphology of the intact microsphere that signify the bigger specific surface area for providing more possible reaction sites for the adsorption–desorption equilibrium of photocatalytic reaction, the introduction of F^? ions that may cause the enhancement of surface acidity and creation of oxygen vacancies under visible light irradiation, the narrower band gap which means needing less energy for the electron hole pair transition.     

Synthesis of Bi2WO6/Bi2O3 Composite with Enhanced Photocatalytic Activity by a Facile One‐step Hydrothermal Synthesis Route

In this study, the characterization and photocatalytic activity of Bi₂WO₆/Bi₂O₃ under visible‐light irradiation was investigated in detail. The results suggested that Bi₂WO₆/Bi₂O₃ can be synthesized by a facile one‐pot hydrothermal route using a super big 200 mL Teflon‐lined autoclave with optimal sodium oleate/Bi molar ratio of 1.25. Through the characterization of Bi₂WO₆/Bi₂O₃ by X‐ray diffraction, scanning electron microscopy, X‐ray photoelectron spectroscopy, Fourier transform infrared, UV‐vis diffuse reflectance spectra and Photoluminescence spectra, it was found that the as‐prepared composite possessed smaller crystallite size and higher visible‐light responsive than the pure Bi₂WO₆. Moreover, it was expected that the as‐prepared composites exhibited enhanced photocatalytic activity for the degradation of Rhodamine B under visible‐light irradiation, which could be ascribed to their improved light absorption property and the reduced recombination of the photogenerated electrons and holes during the photocatalytic reaction. In general, this study could provide a principle method to synthesize Bi₂WO₆/Bi₂O₃ with enhanced photocatalytic activity by one‐step hydrothermal synthesis route for environmental purification.     

Sonophotocatalytic treatment of diazinon using visible light‐driven Ce:Cu‐1,4‐BDOAH2 photocatalyst in a batch‐mode process: Response surface methodology and optimization

Cu–1,4‐benzenedioxyacetic acid (Cu‐1,4‐BDOAH₂) with a narrow band gap (2.52 eV) was synthesized and doped with Ce to afford Ce:Cu‐1,4‐BDOAH₂ as an efficient photocatalyst with narrower band gap (2.39 eV). The prepared Cu‐1,4‐BDOAH₂ and Ce:Cu‐1,4‐BDOAH₂ were characterized using Fourier transform infrared, energy‐dispersive X‐ray, diffuse reflectance spectroscopies, scanning electron microscopy and X‐ray diffraction. The sonophotocatalytic degradation of diazinon was carried out in a batch‐mode reactor using visible light‐driven Ce:Cu‐1,4‐BDOAH₂ photocatalyst as well as ultrasonic irradiation. The narrow band gap of the photocatalyst means that it can be activated under visible light illumination. The effects of operational parameters such as initial diazinon concentration (5–25 mg l^?1), pH (2–10), photocatalyst dosage (10–30 mg) and irradiation time (10–30 min) on the sonophotocatalytic degradation efficiency were investigated using central composite design under response surface methodology. The optimization process was studied using desirability function and the results indicated 99.8% degradation, which was obtained at optimum values of 25 mg l^?1, 6, 20 mg and 20 min for the initial concentration of diazinon, pH, photocatalyst dosage and irradiation time, respectively. Reusability experiments of Ce:Cu‐1,4‐BDOAH₂ photocatalyst showed that it is quite stable with excellent catalytic activity even after five cycles.     

Controllable Synthesis of Porphyrin‐Based 2D Lanthanide Metal–Organic Frameworks with Thickness‐ and Metal‐Node‐Dependent Photocatalytic Performance

Synthesizing 2D metal–organic frameworks (2D MOFs) in high yields and rational tailoring of the properties in a predictable manner for specific applications is extremely challenging. Now, a series of porphyrin‐based 2D lanthanide MOFs (Ln‐TCPP, Ln=Ce, Sm, Eu, Tb, Yb, TCPP=tetrakis(4‐carboxyphenyl) porphyrin) with different thickness were successfully prepared in a household microwave oven. The as‐prepared 2D Ln‐TCPP nanosheets showed thickness‐dependent photocatalytic performances towards photooxidation of 1,5‐dihydroxynaphthalene (1,5‐DHN) to synthesize juglone. Particularly, the Yb‐TCPP displayed outstanding photodynamic activity to generate O₂^? and ¹O₂. This work not only provides fundamental insights into structure designing and property tailoring of 2D MOFs nanosheets, but also pave a new way to improve the photocatalytic performance.     

Visible‐Light‐Induced Photoredox Catalysis with a Tetracerium‐Containing Silicotungstate

The development of visible‐light‐induced photocatalysts for chemoselective functional group transformations has received considerable attention. Polyoxometalates (POMs) are potential materials for efficient photocatalysts because their properties can be precisely tuned by changing their constituent elements and structures and by the introduction of additional metal cations. Furthermore, they are thermally and oxidatively more stable than the frequently utilized organometallic complexes. The visible‐light‐responsive tetranuclear cerium(III)‐containing silicotungstate TBA₆[{Ce(H₂O)}₂{Ce(CH₃CN)}₂(μ₄‐O)(γ‐SiW₁₀O₃₆)₂] (CePOM; TBA=tetra‐n‐butylammonium) has now been synthesized; when CePOM was irradiated with visible light (λ>400 nm), a unique intramolecular Ce^III‐to‐POM(W^VI) charge transfer was observed. With CePOM, the photocatalytic oxidative dehydrogenation of primary and secondary amines as well as the α‐cyanation of tertiary amines smoothly proceeded in the presence of O₂ (1 atm) as the sole oxidant.     

Enhanced Photocatalytic Activity of MIL‐125 by Post‐Synthetic Modification with CrIII and Ag Nanoparticles

NH₂‐MIL‐125, [Ti₈O₈(OH)₄(bdc‐NH₂)₆] (bdc^2?=1,4‐benzene dicarboxylate) is a highly porous metal–organic framework (MOF) that has a band gap lying within the ultraviolet region at about 2.6 eV. The band gap may be reduced by a suitable post‐synthetic modification of the nanochannels using conventional organic chemistry methods. Here, it is shown that the photocatalytic activity of NH₂‐MIL‐125 in the degradation of methylene blue under visible light is remarkably augmented by post‐synthetic modification with acetylacetone followed by Cr^III complexation. The latter metal ion extends the absorption from the ultraviolet to the visible light region (band gap 2.21 eV). The photogenerated holes migrate from the MOF’s valence band to the Cr^III valence band, promoting the separation of holes and electrons and increasing the recombination time. Moreover, it is shown that the MOF’s photocatalytic activity is also much improved by doping with Ag nanoparticles, formed in situ by the reduction of Ag⁺ with the acetylacetonate pendant groups (the resulting MOF band gap is 2.09 eV). Presumably, the Ag nanoparticles are able to accept the MOF’s photogenerated electrons, thus avoiding electron–hole recombination. Both, the Cr‐ and Ag‐bearing materials are stable under photocatalytic conditions. These findings open new avenues for improving the photocatalytic activity of MOFs.     

Visible-light photocatalytic activity of the metastable Bi20TiO32 synthesized by a high-temperature quenching method

Metastable Bi₂₀TiO₃₂ samples were synthesized by a high-temperature quenching method using α-Bi₂O₃ and anatase TiO₂ as raw materials. The photocatalytic activity of the as-prepared samples was measured with the photodegradation of methyl orange at room temperature under visible light irradiation. The Bi₂₀TiO₃₂ samples exhibited good absorption in the visible light region with a band gap of about 2.38 eV and the band structure of Bi₂₀TiO₃₂ was studied. Photodegradation against methyl orange was much better than α-Bi₂O₃ prepared by the same way. The photocatalytic activity of Bi₂₀TiO₃₂ samples is supposed to be associated with the hybridized Bi 6s and O 2p orbitals. In addition, the dispersive characteristic of Bi 6s orbital in the hybridized valence band facilitates the mobility of the photogenerated carriers and hampers their recombination.     

Carbonyl‐Grafted g‐C3N4 Porous Nanosheets for Efficient Photocatalytic Hydrogen Evolution

Carbonyl‐grafted g‐C₃N₄ porous nanosheets (COCNPNS) were fabricated by means of a two‐step thermal process using melamine and oxalic acid as starting reagents. The combination of melamine with oxalic acid to form a melamine–oxalic acid supramolecule as a precursor is key to synthesizing carbonyl‐grafted g‐C₃N₄. The bulk carbonyl‐grafted g‐C₃N₄ (COCN) was further thermally etched onto porous nanosheets by O₂ under air. In such a process, the carbonyl groups were partly removed and the obtained sample showed remarkably enhanced visible‐light harvesting and promoted the separation and transfer of photogenerated electrons and holes. With its unique porous structure and enhanced light‐harvesting capability, under visible‐light illumination (λ >420 nm) the prepared COCNPNS exhibited a superior photocatalytic hydrogen evolution rate of 83.6 μmol h⁻¹, which is 26 times that of the p‐CN obtained directly from thermal polycondensation of melamine.     

Ultrathin Metal–Organic Framework Nanosheets with Ultrahigh Loading of Single Pt Atoms for Efficient Visible‐Light‐Driven Photocatalytic H2 Evolution

A surfactant‐stabilized coordination strategy is used to make two‐dimensional (2D) single‐atom catalysts (SACs) with an ultrahigh Pt loading of 12.0 wt %, by assembly of pre‐formed single Pt atom coordinated porphyrin precursors into free‐standing metal–organic framework (MOF) nanosheets with an ultrathin thickness of 2.4±0.9 nm. This is the first example of 2D MOF‐based SACs. Remarkably, the 2D SACs exhibit a record‐high photocatalytic H₂ evolution rate of 11 320 μmol g^?1 h^?1 via water splitting under visible light irradiation (λ>420 nm) compared with those of reported MOF‐based photocatalysts. Moreover, the MOF nanosheets can be readily drop‐casted onto solid substrates, forming thin films while still retaining their photocatalytic activity, which is highly desirable for practical solar H₂ production.     

AgBi(WO4)2: A New Modification Material to Bi2WO6 for Enhanced and Stable Visible‐Light Photocatalyic Performance

In this work, we report a novel AgBi(WO₄)₂–Bi₂WO₆ heterostructure, which was designed and synthesized by using a simple hydrothermal method. Methyl orange was used as a representative dye indicator to evaluate the visible‐light catalytic activity and the catalytic mechanism was investigated. The as‐synthesized AgBi(WO₄)₂–Bi₂WO₆ composite displayed a 43 times higher photocatalytic activity than Bi₂WO₆. Owing to the matched band gap and distinctive heterostructure, AgBi(WO₄)₂–Bi₂WO₆ reveals a high visible‐light response and high‐efficiency utilization of both photogenerated electrons and holes. AgBi(WO₄)₂ reveals a similar energy level to and good lattice match with Bi₂WO₆, which are favorable qualities for band bending and fluent electron transfer. Furthermore, the photoexcited electrons can produce oxygen to generate ^.O₂^? radicals, which is vital for the overall utilization of both holes and electrons. This is the first example of AgBi(WO₄)₂ being used as photocatalytic material.     

Plasmonic Ag/AgCl‐modified bismuth subcarbonate with enhanced visible light photocatalytic activity

Plasmonic Ag/AgCl‐modified bismuth subcarbonate (Bi₂O₂CO₃) composites were prepared by a multistep process with hydrothermal, deposition, and photoreduction in the absence of organic capping agents. The properties of the obtained Ag/AgCl/Bi₂O₂CO₃ samples were characterized using X‐ray diffraction, field emission scanning electron microscopy and X‐ray photoelectron, UV–visible diffuse reflectance, and photoluminescence spectroscopies. The results reveal that Ag/AgCl nanoparticles are dispersed on the Bi₂O₂CO₃ surface to achieve plasmonic Ag/AgCl/Bi₂O₂CO₃. The Ag/AgCl/Bi₂O₂CO₃ nanocomposites show improved rhodamine B (RhB) adsorption capacity and photocatalytic activity compared with pure Bi₂O₂CO₃ and Ag/AgCl. In addition, the Ag/AgCl/Bi₂O₂CO₃ composite with 20 wt% Ag/AgCl exhibits the highest photocatalytic activity and remains stable for the photodegradation of RhB under visible light. The enhanced photocatalytic activity of Ag/AgCl/Bi₂O₂CO₃ may be attributed to the surface plasmon resonance effect of in situ generated Ag nanoparticles and synergistic effect of Ag/AgCl and Bi₂O₂CO₃, which increase the separation efficiency of photogenerated electron–hole pairs under visible light irradiation.     

Structural characterization and photocatalytic properties of novel Bi<Subscript>2</Subscript>FeVO<Subscript>7</Subscript>

Bi₂FeVO₇ was prepared by a solid-state reaction technique for the first time and the structural and photocatalytic properties of Bi₂FeVO₇ were studied. The results shows that this compound crystallized in the tetragonal crystal system with space group I4/mmm. Moreover, the band gap of Bi₂FeVO₇ was estimated to be about 2.22(6) eV. For the photocatalytic water splitting reaction, H₂ or O₂ evolution was observed from pure water with Bi₂FeVO₇ as the photocatalyst by ultraviolet light irradiation. Degradation of aqueous methylene blue (MB) dye by photocatalytic way over this compound was further studied under visible light irradiation. Bi₂FeVO₇ shows higher catalytic activity compared to TiO₂ (P-25) for MB photocatalytic degradation under visible light irradiation. Complete removal of aqueous MB was realized after visible light irradiation for 170 min with Bi₂FeVO₇ as the photocatalyst. The reduction of the total organic carbon (TOC) and the formation of inorganic products, SO ₄ ²⁻ and NO ₃ ⁻ revealed the continuous mineralization of aqueous MB during the photocatalytic course.     

Synthesis of Hierarchical Macro‐/Mesoporous Solid‐Solution Photocatalysts by a Polymerization–Carbonization–Oxidation Route: The Case of Ce0.49Zr0.37Bi0.14O1.93

A hierarchical macro‐/mesoporous Ce_0.49Zr_0.37Bi_0.14O_1.93 solid‐solution network has been synthesized on a large scale by means of a simple and general polymerization–carbonization–oxidation synthetic route. The as‐prepared product has been characterized by SEM, XRD, TEM, BET surface area measurement, UV/Vis diffuse‐reflectance spectroscopy, energy‐dispersive X‐ray spectroscopy (EDS), and photoelectrochemistry measurements. The photocatalytic activity of the product has been demonstrated through the photocatalytic degradation of methyl orange. Structural characterization has indicated that the hierarchical macro‐/mesoporous solid‐solution network not only contains numerous macropores, but also possesses an interior mesoporous structure. The mesopore size and BET surface area of the network have been measured as 2–25 nm and 140.5 m² g^?1, respectively. The hierarchical macro‐/mesoporous solid‐solution network with open and accessible pores was found to be well‐preserved after calcination at 800 °C, indicating especially high thermal stability. Due to its high specific surface area, the synergistic effect of the coupling of macropores and mesopores, and its high crystallinity, the Ce_0.49Zr_0.37Bi_0.14O_1.93 solid‐solution material shows a strong structure‐induced enhancement of visible‐light harvest and exhibits significantly improved visible‐light photocatalytic activity in the photodegradation of methyl orange compared with those of its other forms, such as mesoporous hollow spheres and bulk particles.     

Amino‐Assisted Anchoring of CsPbBr3 Perovskite Quantum Dots on Porous g‐C3N4 for Enhanced Photocatalytic CO2 Reduction

Halide perovskite quantum dots (QDs) have great potential in photocatalytic applications if their low charge transportation efficiency and chemical instability can be overcome. To circumvent these obstacles, we anchored CsPbBr₃ QDs (CPB) on NH_x‐rich porous g‐C₃N₄ nanosheets (PCN) to construct the composite photocatalysts via N?Br chemical bonding. The 20 CPB‐PCN (20 wt % of QDs) photocatalyst exhibits good stability and an outstanding yield of 149 μmol h^?1 g^?1 in acetonitrile/water for photocatalytic reduction of CO₂ to CO under visible light irradiation, which is around 15 times higher than that of CsPbBr₃ QDs. This study opens up new possibilities of using halide perovskite QDs for photocatalytic application.     

Bi<Subscript>2</Subscript>O<Subscript>3</Subscript>/BiFeO<Subscript>3</Subscript> heterostructure: preparation,characterization, and photocatalytic activity

Bi₂O₃/BiFeO₃ composite was successfully fabricated by a conventional sol–gel method and structural properties were characterized based on X-ray diffractometer, scanning electron microscope, transmission electron microscope, energy-dispersive X-ray analyzer, nitrogen adsorption–desorption measurement, and UV–visible diffuse reflectance spectroscopy. Bi₂O₃/BiFeO₃ had a good absorption for visible light, which was benefit to photocatalytic activity. The highest degradation efficiency was obtained when the content of Bi₂O₃ in Bi₂O₃/BiFeO₃ was 63.9%. Effect of experimental conditions was investigated, and the highest photocatalytic activity of Bi₂O₃/BiFeO₃ was observed at photocatalyst dosage of 0.5 g/L, initial BPA concentration of 10 mg/L, and solution pH of 6.3. Bi₂O₃/BiFeO₃ photocatalyst exhibited enhanced photocatalytic activity for BPA, and the reaction rate constant over Bi₂O₃/BiFeO₃ composite was 2.23, 3.65, and 8.71 times higher than that of BiFeO₃, Bi₂O₃ and commercial TiO₂ (P25), respectively. Bi₂O₃/BiFeO₃ showed high photocatalytic activity after three cycles, suggesting that it was a stable photocatalyst. The possible photocatalytic mechanism has been discussed on the basis of the theoretical calculation and the experimental results. The hydroxyl and superoxide radicals together with photogenerated holes played significant roles in the photocatalytic reaction.     

Two‐Dimensional Cobalt‐/Nickel‐Based Oxide Nanosheets for High‐Performance Sodium and Lithium Storage

Two‐dimensional (2D) nanomaterials are one of the most promising types of candidates for energy‐storage applications due to confined thicknesses and high surface areas, which would play an essential role in enhanced reaction kinetics. Herein, a universal process that can be extended for scale up is developed to synthesise ultrathin cobalt‐/nickel‐based hydroxides and oxides. The sodium and lithium storage capabilities of Co₃O₄ nanosheets are evaluated in detail. For sodium storage, the Co₃O₄ nanosheets exhibit excellent rate capability (e.g., 179 mA h g^?1 at 7.0 A g^?1 and 150 mA h g^?1 at 10.0 A g^?1) and promising cycling performance (404 mA h g^?1 after 100 cycles at 0.1 A g^?1). Meanwhile, very impressive lithium storage performance is also achieved, which is maintained at 1029 mA h g^?1 after 100 cycles at 0.2 A g^?1. NiO and NiCo₂O₄ nanosheets are also successfully prepared through the same synthetic approach, and both deliver very encouraging lithium storage performances. In addition to rechargeable batteries, 2D cobalt‐/nickel‐based hydroxides and oxides are also anticipated to have great potential applications in supercapacitors, electrocatalysis and other energy‐storage‐/‐conversion‐related fields.