Flower-like Hierarchical Architectures Research Articles

Synthesis of Pd-Doped SnO2 and Flower-like Hierarchical Structures for Efficient and Rapid Detection of Ethanolamine.

In this study, we successfully synthesized a Pd-doped SnO2 (Pd-SnO2) material with a flower-like hierarchical structure using the solvothermal method. The material's structural proper-ties were characterized employing techniques such as XRD, XPS, FESEM and HRTEM. A gas sensor fabricated from the 2.0 mol% Pd-SnO2 material demonstrated exceptional sensitivity (Ra/Rg = 106) to 100 ppm ethanolamine at an operating temperature of 150 °C, with rapid response/recovery times of 10 s and 12 s, respectively, along with excellent linearity, selectivity, and stability, and a detection limit down to 1 ppm. The superior gas-sensing performance is attributed to the distinctive flower-like hierarchical architecture of the Pd-SnO2 and the lattice distortions introduced by Pd doping, which substantially boost the material's sensing characteristics. Further analysis using density functional theory (DFT) has revealed that within the Pd-SnO2 system, Sn exhibits strong affinities for O and N, leading to high adsorption energies for ethanolamine, thus enhancing the system's selectivity and sensitivity to ethanolamine gas. This research introduces a novel approach for the efficient and rapid detection of ethanolamine gas.

Dual Strategy of Morphology Optimization and Interlayer Expansion in VS2 Cathode Toward High-Performance Mg-Li Hybrid Ion Batteries.

Combining the merits of the dendrite-free formation of a Mg anode and the fast kinetics of Li ions, the Mg-Li hybrid ion batteries (MLIBs) are considered an ideal energy storage system. However, the lack of advanced cathode materials limits their further practical application. Herein, we report a dual strategy of morphology optimization and interlayer expansion for the construction of hierarchical flower-like VS2 architecture coated by N-doped amorphous carbon layers. This tailored hierarchical flower-like structure coupled with homogeneous N-doped amorphous carbon layers cooperatively provide more active sites and buffer volume changes, thus realizing the enhancement of capacity and structural stability. Moreover, the enlarged interlayer spacing caused by the cointercalation of polyvinylpyrrolidone and ammonium ions can effectively promote the charge transfer rate and facilitate the rapid ion diffusion, as further demonstrated by electrochemical results and theoretical calculations. These features endow the hierarchical flower-like VS2 cathode with superior specific energy density (644.4 Wh kg-1, average voltage of 1.2 V vs Mg2+/Mg) and excellent rate capability (181.1 mAh g-1 at 2000 mA g-1). Systematic ex situ characterization measurements are employed to reveal the ion storage mechanism, which confirms that Li+ storage plays a leading role in the capacity contribution of MLIBs. Our strategy is in favor of providing useful insights to design and construct MLIBs with high energy density and excellent rate performance.

Effective strategy for alleviation of oil contamination in marine via the superhydrophobic biochar: Performances, mechanisms and environmental recalcitrance

The performance of layered double hydroxides (LDH)-biochar composite on alleviating oil spill pollution is poorly understood. A superhydrophobic biochar (NCY) was synthesized from the pristine wood chips biochar (WCB) after the surface deposition of NiCo-LDH (NCB) and hydrophobic modification with stearate. The oil removal potential of the designed biochars was investigated via the diesel oil/crude oil adsorption experiments and the environmental recalcitrance evaluation. The compared characterization results revealed that NiCo-LDH was successfully deposited onto biochar matrix via the electrostatic attraction and pore filling effect, which facilitated a special flower-like hierarchical architecture rough surface for biochar and hinder the multi-layer stacking of LDH. Benefit from the constructed hierarchical architecture, the occupancy of oxygen-containing functional groups and hydrophobic modification of stearate, the water contact angle of NCY (156°) was remarkably larger than NCB (117°) and WCB (50.1°), which exhibit a superhydrophobic. The maximum diesel oil sorption capacities of biochars increased from 3.28 g/g in WCB to 5.64 g/g in NCB and 11.6 g/g in NCY, as well as the maximum crude oil sorption capacities of biochars showed a similar trend (WCB: 4.64 g/g, NCB: 8.74 g/g, NCY: 18.6 g/g). Accordingly, NCY showed higher oil adsorption capacity than NCB and WCB mainly due to the enhanced hydrophobic forces and the π-π electron donor-acceptor interaction resulted from lower amount of O-containing functional groups and superhydrophobic surface wettability. Furthermore, the application of LDH remarkably improved the environmental recalcitrance of biochar (resist to the chemical oxidation and thermal decomposition in marine) due to the coating of NiCo-LDH could enhance the bulk stability of biochar and increase the liable carbon content in biochar. This study proved that the application of NiCo-LDH and stearate could be an effective approach for improve the oil pollution remediation capacity and the environmental recalcitrance of biochar.

Fabrication of oxygen-vacancy-adjustable Yb3+/Er3+ co-doped BiOBr 3D flowerlike hierarchical architectures with enhanced photocatalytic activity under broad spectrum (UV/vis/NIR) excitation

A novel Yb3+/Er3+ co-doped BiOBr photocatalyst with 3D flowerlike hierarchical architectures were successfully fabricated through self-assembled process without any templates under hydrothermal conditions, and the structure and properties of the photocatalysts were characterized. The results indicate that Yb3+ ions and Er3+ ions are successfully doped into the lattice of BiOBr, and the as-obtained photocatalyst can respond the NIR light and emit red and green light due to the up-conversion effect of the rare-earth ions. Meanwhile, with co-doped Yb3+/Er3+ ions content increasing, oxygen vacancy concentration in the photocatalyst rises. The oxygen vacancy will form the intermediate energy band, which can decrease the photon energy required for electronical transition, and thus help to utilize the luminous energy generated by up-conversion luminescence. Moreover, the appropriate introduction of defects (oxygen vacancy defect and impurity atom) can further promote the transfer and separation efficiency of photo-generated carriers. Hence, Yb3+/Er3+ co-doped BiOBr photocatalyst exhibits enhanced photocatalytic properties under broad spectrum (UV/vis/NIR) excitation, which is about 4 times as high as that of pure BiOBr.

Customized self-assembled bimetallic hybrid nanoflowers promoting the robustness of D-allulose 3-epimerase

Enzyme-based hybrid nanoflowers, a green biocatalyst technology employing metal ions as the main driving force of enzyme immobilization without participating in the catalytic reaction, have been extensively explored to increase enzyme robustness. Here, a customized self-assembled protein-bimetallic hybrid nanoflower system (HNF) was designed to immobilize D-allulose 3-epimerase (DAEase) with a hierarchical flower-like architecture. The tailored DAEase-HNFs were extremely stable in acidic conditions, retaining more than 70 % of their initial activity after incubation in aqueous solution at pH 3.0–6.0 for 4 h. They were also durable, retaining 92.4 % relative activity after 8 consecutive cycles, and maintaining 82.3 % relative activity after storage for 30 days at 4 °C. Molecular dynamics (MD) simulations were performed to probe the self-assembly processes related to the increased robustness of the encapsulated DAEase by investigating the conformational changes in the gating switch helix of the substrate entrance, hydrogen bond networks, and the catalytic cavity. Our data indicate that HNFs are a promising immobilization strategy to improve the robustness and durability of DAEase.

A MOF-derived porous In2O3 flower-like hierarchical architecture sensor: near room-temperature preparation and fast trimethylamine sensing performance

A MOF-derived porous In2O3 flower-like hierarchical architecture sensor is prepared at near room temperature, which exhibits a high response and a fast response speed towards trimethylamine.

Novel FeVO4/CuS heterojunction nanocomposite as a high-performance visible-light-active photocatalyst for ibuprofen degradation in aquatic media

Herein, we report the fabrication of type-II FeVO4/CuS heterojunction nanocomposite by a versatile reflux-assisted co-precipitation procedure. The hybrid FeVO4/CuS heterostructure with a band gap of 1.95 eV, demonstrated excellent degradation efficiency of ibuprofen antibiotic (∼95%) after 90 min of visible-light irradiation, which displayed remarkably enhanced photocatalytic degradation (1.75 fold higher) in comparison to pristine FeVO4 structure. The superior photocatalytic performance of the FeVO4/CuS nanocomposite is associated with hierarchical flower-like architectures, great visible-light harvesting, and poor electron-hole recombination due to the fabrication of type-II heterojunction. In addition, we introduced an obvious photocatalytic destruction mechanism, which indicated that superoxides (•O2−) and holes (h+) were the invasive species in antibiotic degradation on the FeVO4/CuS photocatalyst. Consequently, the as-prepared FeVO4/CuS heterojunction photocatalyst is a promising candidate for the development of future photocatalysts towards the elimination of antibiotics under sun light irradiation at short process time.

A comparative study on the acetone sensing properties of ZnO disk pairs, flowers, and walnuts prepared by hydrothermal method

The synthesis of sensing materials in suitable morphology and microstructure is critical for fabricating fast, highly responsive, and reliable acetone sensing devices for human safety and health. Herein, ZnO disk pairs, flower-like, and walnut-like hierarchical architectures were prepared by varying the relative amount of citric acid and NaOH to Zinc acetate dihydrate during the hydrothermal process. At the lowest prime working temperature, the ZnO flowers exhibited the highest gas response, stability, and selectivity towards acetone due to the highest degree of (001) facet exposure and Schottky barrier height, the largest BET specific surface area and BJH average pore size. At the same temperature, the ZnO walnuts displayed the shortest response/recovery time and the lowest limit of detection due to the highest content of surface oxygen vacancy and the high reactivity of adsorbed O2– ions; the ZnO disk pairs showed unique selectivity towards ethylene glycol monomethyl ether due to the highest degree of (100) facet exposure and the smallest BJH average pore size. Replacing Zinc acetate dehydrate by Zinc nitrate hexahydrate improved the acetone sensing performance of the ZnO flowers in terms of response value, stability, and selectivity at the expense of a higher LOD and a slower recovery speed.

Synthesis of carnation flower-like Bi2O2CO3 photocatalyst and its promising application for photoreduction of Cr(VI)

In this study, we have synthesized high-quality carnation flower-like Bi2O2CO3 hierarchical architectures via a hydrothermal route. The as-synthesized Bi2O2CO3 photocatalyst was systematically characterized and analyzed by various techniques. Its photocatalytic activity was investigated by simulated-sunlight driving photoreduction of Cr(VI), revealing that it exhibits excellent photocatalytic removal of Cr(VI). The effects of various factors (H2SO4, NaOH, Cr(VI) concentration, catalyst dosage) on the photoreduction efficiency and involved mechanism were systematically investigated and discussed. In addition, we have also systematically examined the effects of various parameters (H2SO4 concentration, 1,5-diphenylcarbazide (DPC) concentration, Cr(VI) concentration, reaction time t and reaction temperature T) on the absorbance of the Cr(VI) solution, with the aim of correctly determining the Cr(VI) concentration according to UV–vis absorption measurements using DPC as the chromogenic agent.

Hollow flower-like Cr2V4O13 hierarchical micro-nano architectures: Controlled self-assembly synthesis and the outstanding catalytic performances for ammoxidation of chlorotoluenes

The controlled synthesis of hierarchical micro-nano materials has attracted great interest due to their wide applications in catalysis and many other fields. In this paper, hollow flower-like Cr2V4O13 hierarchical micro-nano structures were successfully synthesized via a facile hydrothermal process and subsequent calcination treatment. The samples were characterized by XRD, TGA, FT-IR, SEM, TEM, XPS, TPR and N2 adsorption-desorption. SEM and TEM micrographs showed that the as-obtained Cr2V4O13 had a three-dimensional (3-D) hollow flower-like superstructure assembled by numerous nanoflakes with widths of 0.2 µm and thickness of about 30 nm. The micro-nano structured Cr2V4O13 exhibited high activity and selectivity in continuous ammoxidation of chlorotoluenes to the corresponding chlorobenzonitriles. To the best of our knowledge, this is the highest activity reported for selective ammoxidation of chlorotoluenes with Cr-V-O binary catalysts. The unique catalytic behavior of Cr2V4O13 was ascribed to the micro-nano hierarchical architecture and the increased active surface sites.

Flower-like MoS2 hierarchical architectures assembled by 2D nanosheets sensitized with SnO2 quantum dots for high-performance NH3 sensing at room temperature

Flower-like MoS2 hierarchical architectures assembled by ultrathin 2D nanosheets decorated with SnO2 quantum dots (QDs) were successfully prepared through a solvothermal method and used for room-temperature NH3 sensing detection. The morphology and structure of as-prepared hierarchical architectures were fully characterized, showing that SnO2 QDs with uniform particle size of 2–4 nm were uniformly distributed on the ultrathin nanosheets of MoS2 hierarchical architectures. SnO2 QDs@MoS2 composites based gas sensor exhibited a high response of 8.6 and short response/recovery times of 6 s/121 s to 100 ppm NH3 with good selectivity, excellent repeatability, and outstanding long-term stability at room temperature of 25 °C. Such highly enhanced response toward NH3 was ascribed to the synergistic effect between active SnO2 QDs with abundant dangling bonds and MoS2 nanosheets with large specific surface area and high carrier mobility. This work presented a potential room-temperature sensing material and revealed the underlying sensitization mechanism of the quantum dots, offering new ideas for the development of low-temperature gas sensors.

Hierarchical flower-like architecture of nickel phosphide anchored with nitrogen-doped carbon quantum dots and cobalt oxide for advanced hybrid supercapacitors

The exploitation of hybrid supercapacitors with excellent electrochemical properties is of great significance for energy storage systems. Herein, a three-dimensional hierarchical flower-like architecture of nickel phosphide (Ni2P) decorated with nitrogen-doped carbon quantum dots (N-CQDs) and cobalt oxide (Co3O4) is constructed by an effective two-step hydrothermal strategy followed by in situ phosphorization process. Introducing N-CQDs with superior electrochemical characteristics can not only induce the formation of N-CQDs deposited nickel hydroxide (Ni(OH)2) flower-like architecture but also significantly enhance the electrochemical features of Ni(OH)2 nanosheets. After combination with Co3O4 nanoparticles and phosphorization treatment, an advanced cathode of Ni2P/Co3O4/N-CQDs with enriched surface phosphate ions is obtained, which possesses an ultra-high capacity of 1044 C g−1 (2088 F g−1) at 1 A g−1 with a splendid rate capacity of 876 C g−1 (1752 F g−1) at 20 A g−1. Moreover, a device assembled by Ni2P/Co3O4/N-CQDs hierarchical flower-like architecture and p-phenylenediamine functionalized reduced graphene oxide (PPD/rGO) nanosheets depicts a commendable energy density of 53.5 Wh kg−1 at 772.9 W kg−1. This work provides a novel hierarchical multi-component electrode material with decent electrochemical capacities for hybrid supercapacitors, which has a broad prospect in energy storage devices.

Bimetallic SnS2/NiS2@S-rGO nanocomposite with hierarchical flower-like architecture for superior high rate and ultra-stable half/full sodium-ion batteries

Bimetallic SnS2/NiS2 with hierarchical flower-like architecture wrapped by interconnected S-doped rGO 3D network (SnS2/NiS2@S-rGO) was synthesized by facile solvothermal strategy. The unique hierarchical flower-like architecture endows the whole electrode with sufficient Na+ active site and contact area to electrolyte, which could buffer the volume expansion and shorten the diffusion length of Na+. The interconnected S-rGO 3D network increases the whole electrochemical conductivity and accelerates the Na+ diffusion and electron transmission. In addition, the synergy effect of NiS2 and SnS2 components further enhanced the electrochemical performance. The obtained SnS2/NiS2@S-rGO electrode exhibits outstanding rate performance (330.4 mAh g−1 at 10 A g−1) and ultralong cycle stability (340.7 mAh g−1 after 5000 cycles at 2 A g−1) for sodium-ion half-cell. In addition, Na3V2(PO4)3@rGO//SnS2/NiS2@S-rGO sodium-ion full-cells are successfully assembled and deliver capacity of 472.8 mAh g−1 after 50 cycles at 0.1 A g−1. Ex-situ XRD, Raman spectra and HRTEM images, and a series of electrochemical analyses were employed to investigate the sodium-ion storage mechanism and ion diffusion kinetics of the SnS2/NiS2@S-rGO electrode. These results uncover the promising potential of SnS2/NiS2@S-rGO with hierarchical flower-like architecture toward SIBs.

Layered Double Hydroxide-Based Gas Sensors for VOC Detection at Room Temperature.

Miniaturized low-cost sensors for volatile organic compounds (VOCs) have the potentiality to become a fundamental tool for indoor and outdoor air quality monitoring, to significantly improve everyday life. Layered double hydroxides (LDHs) belong to the class of anionic clays and are largely employed for NOx detection, while few results are reported on VOCs. In this work, a novel LDH coprecipitation method is proposed. For the first time, a study comparing four LDHs (ZnAl–Cl, ZnFe–Cl, ZnAl–NO3, and MgAl–NO3) is carried out to investigate the sensing performances. As explored through several microscopy and spectroscopy analyses, LDHs show a morphology characterized by a large surface area and a three-dimensional hierarchical flowerlike architecture with micro- and nanopores that induce a fast diffusion and highly effective surface interaction of the target gases. The fabricated sensors, operating at room temperature, are able to reversibly and selectively detect acetone, ethanol, ammonia, and chlorine vapors, reaching significant sensing response values up to 6% at 21 °C. The results demonstrate that by changing the LDHs’ composition, it is possible to modulate the sensitivity and selectivity of the sensor, helping the discrimination of different analytes, and the consequent integration on a sensor array paves the way for electronic nose development.

Rational design of MoS2/g-C3N4/ZnIn2S4 hierarchical heterostructures with efficient charge transfer for significantly enhanced photocatalytic H2 production

The rational design of hierarchical heterojunction photocatalysts with efficient spatial charge separation remains an intense challenge in hydrogen generation from photocatalytic water splitting. Herein, a noble-metal-free MoS2/g-C3N4/ZnIn2S4 ternary heterostructure with a hierarchical flower-like architecture was developed by in situ growth of 3D flower-like ZnIn2S4 nanospheres on 2D MoS2 and 2D g-C3N4 nanosheets. Benefiting from the favorable 2D-2D-3D hierarchical heterojunction structure, the resultant MoS2/g-C3N4/ZnIn2S4 nanocomposite loaded with 3 wt% g-C3N4 and 1.5 wt% MoS2 displayed the optimal hydrogen evolution activity (6291 μmol g−1 h−1), which was a 6.96-fold and 2.54-fold enhancement compared to bare ZnIn2S4 and binary g-C3N4/ZnIn2S4, respectively. Structural characterizations reveal that the significantly boosted photoactivity is closely associated with the multichannel charge transfer among ZnIn2S4, MoS2, and g-C3N4 components with suitable band-edge alignments in the composites, where the photogenerated electrons migrate from g-C3N4 to ZnIn2S4 and MoS2 through the intimate heterojunction interfaces, thus enabling efficient electron-hole separation and high photoactivity for hydrogen evolution. In addition, the introduction of MoS2 nanosheets highly benefits the improved light-harvesting capacity and the reduced H2-evolution overpotential, further promoting the photocatalytic H2-evolution performance. Moreover, the MoS2/g-C3N4/ZnIn2S4 ternary heterostructure possesses prominent stability during the photoreaction process owing to the migration of photoinduced holes from ZnIn2S4 to g-C3N4, which is deemed to be central to practical applications in solar hydrogen production.

Photocatalytic purification of simulated dye wastewater in different pH environments by using BaTiO3/Bi2WO6 heterojunction photocatalysts

Abstract To reveal the photodegradation process of mixture dye solutions in different pH environments by photocatalysts is a key point to promote the practical application of potocatalysis technology in purifying industrial dye wastewater. Herein we report the photocatalytic degradation of various organic dyes (MO, RhB, MB) and MO/RhB/MB mixture solutions in different pH environments by using novel BaTiO3/Bi2WO6 (BTO/BWO) heterojunction composites as the photocatalyst and simulated sunlight as the light source. The BTO/BWO heterojunction photocatalysts were prepared by immobilizing BTO particles onto rose flower-like BWO hierarchical architectures. Among the as-derived samples, the 15 wt%BTO/BWO composite is determined to have the highest photodegradation performance, which is ascribed to the efficient separation of photoexcited electron/hole pairs due to the Z-scheme electron transfer mechanism. The photodegradation of the dyes is found to be highly dependent on the acidic–alkaline environments. Moreover, an interesting competitive photodegradation phenomenon between the dyes is observed in the MO/RhB/MB mixture solutions. Superoxide (•O2−) and hydroxyl (•OH) radicals are suggested to be the direct reactive species causing the dye photodegradation in the present photocatalytic system.

Layer-by-layer self-assembly of hierarchical flower-like HKUST-1-based composite over amino-tethered SBA-15 with synergistic enhancement for CO2 capture

In this study, a novel HKUST-1-based nanocomposite was fabricated through a facile in-situ solvothermal method using amino-tethered SBA-15 (APTMS-SBA-15) as the matrix. Several characterizations had been applied to study the physicochemical properties of the hybrid material. The APTMS-SBA-15, acting as a structure-directing agent, could not only induce the nucleation of HKUST-1 directionally through the coordination effect between Cu2+ centers and amino groups, but also regulate the growth of the nanocrystals via the confinement effect of mesoporous structure. The HKUST-1 grains transformed from octahedron (10–15 μm) to hierarchical flower-like architecture assembled by lamellar crystals (100–200 nm in thickness). The smaller crystal sizes along with the extra ordered mesopores were conducive to reducing the intragranular mass transfer resistance and shortening the diffusion path of CO2 transport. Compared with pristine HKUST-1, the specific surface area, micropore volume and the amount of exposed metal sites increased simultaneously. Meanwhile, the retained amino could also contribute to polarized surfaces of the framework, thus enhancing the interaction towards CO2 molecules. The adsorption sites originating from HKUST-1 synergized with APTMS-SBA-15 to promote the effective capture of CO2. At 25 °C and 1.0 bar, the CO2 adsorption capacity and CO2/N2 (15%/85%) selectivity of the composite reached 4.93 mmol/g and 18.3, which were increased by 18.5% and 92.6% respectively than those of pure HKUST-1. These findings provided a promising strategy for oriented design and synthesis of MOF-based composites with high efficiency for various gas separation processes.

Flower-like hierarchical architecture of BiOI/ZnO p-n junction composites with high-efficient visible-light photodegradation activities

Photodegradation has been taken as a promising technology in solving global environmental pollution. In this paper, the flower-like hierarchical architecture of BiOI/ZnO p-n junction composites were synthesized by coating BiOI nanosheets on the flower-like hierarchical architecture of ZnO prepared by a simple hydrothermal method. The as-synthesized BiOI/ZnO composites were characterized by various techniques. The photocatalytic activities of the BiOI/ZnO composites were examined by degrading the Methylene Blue under visible-light conditions. The results show that the formation of the p-n junction between n-type ZnO and p-type BiOI has broadened the light absorption range, modified the band gap and specific surface area, facilitated the separation and transfer of photogenerated carriers of BiOI/ZnO composites. The visible-light photodegradation rate for 15 wt% BiOI/ZnO composites reached to 94% in 3 h with excellent reusability. The photodegradation obeys first-order reaction kinetic with rate constant of 15.64 × 10−3 min−1 for 15 wt% BiOI/ZnO, which is 4.4 and 24.3 times of that of ZnO and BiOI, respectively. The photodegradation mechanism was proposed based on the analyses of the energy band gap in the formation of the p-n junction.

Intriguing hierarchical Co@NC microflowers in situ assembled by nanoneedles: Towards enhanced reduction of nitroaromatic compounds via interfacial synergistic catalysis

Developing highly efficient and cost-effective catalyst with tuned microstructure holds great promise in the reduction of nitroaromatic compounds under mild reaction conditions. Herein, we report a new Co@NC-MF catalyst with a fascinating hierarchical flower-like architecture in situ assembled from uniform Co@NC nanoneedles, which can function as a favorable platform for the efficient reduction of nitroaromatic compounds in the presence of NaBH4. In addition with the structural advantage, the characterization and experimental results demonstrate the enormous advantage of interfacial synergistic catalysis in enhancing the catalytic performance. The outside electron-rich N-doped carbon layer as Lewis basic sites and the inside Co nanoparticles are responsible for the adsorption of 4-nitrophenol (4-NP) and generation of active hydrogen species, respectively. This work contributes to the construction of well-integrated composites with well-balanced interface synergy to boost the catalytic performance in various heterogeneous reactions.

In situ direct growth of flower-like hierarchical architecture of CoNi-layered double hydroxide on Ni foam as an efficient self-supported oxygen evolution electrocatalyst

Exploring economical, efficient and robust electrocatalysts toward the oxygen evolution reaction (OER) is one of the key issues in water splitting technology. Nanostructure engineering of electrocatalysts and hybridizing active species with a conductive support represent powerful strategies to enhance the electrocatalytic performance. Herein, we report a facile one-step solvothermal method to directly grow 3D CoNi-layered double hydroxide (LDH) flower-like architectures onto porous and conductive Ni foam (NF) substrate (denoted as CoNi-LDH(2:1)@NF hereafter). The flower-like hierarchical architecture of CoNi-LDHs with open configurations endows CoNi-LDH microflowers with sufficient accessible active sites and efficient mass diffusion paths. Moreover, the in situ direct growth manner ensures an intimate contact between the electroactive CoNi-LDHs and NF substrate and thus the charge transfer resistance is reduced. Consequently, the as-formed self-supported and binder-free electrode of CoNi-LDH(2:1)@NF exhibits an outstanding OER performance with a small overpotential of 283 mV at a relatively large current density of 50 mA cm−2 and a remarkable long-term electrochemical durability in 0.1 M KOH solution, holding great promise in practical scale-up water electrolysis. The present study may open a new avenue to design and fabricate cost-effective and high-efficiency electrocatalysts for energy conversion applications.