NiAl-layered Double Hydroxide Research Articles

High stability and selectivity of butterfly pea flower extract-NiAl LDH-based catalysts in the tetracycline degradation.

Layered double hydroxide (LDH) is an applicable material that can be modified in various ways. Modifications using natural extracts fulfill the principles of "green chemistry." The preparation of butterfly pea flower extract (BPE)-modified NiAl LDH was completed using the calcination and restacking method. The characteristics of the prepared composites were identified through analysis of functional groups, crystal phase, bandgap energy, surface area and surface morphology. Fourier transform-infrared (FT-IR) characterization revealed that the active group of the catalyst is -OH except for NiAl layered double oxide (LDO), which has the metal oxide-like functional groups. X-ray diffraction patterns expressed a typical layered material structure of NiAl LDH dan NiAl LDH-BPE, but not for NiAl LDO and NiAl LDO-BPE. Introducing BPE into NiAl LDH and NiAl LDO effectively decreased the bandgap energy and changed the surface morphology. The prepared catalysts were applied in a batch system with pH 5 to degrade tetracycline (TC). NiAl LDO demonstrated the highest activity as a catalyst in TC degradation, with a 93.61% degradation rate. In contrast, NiAl LDO-BPE demonstrated the highest structural stability in TC degradation and repeated use, with an initial degradation percentage of 82.58% and a fifth regeneration percentage of 71.4%.

Custard apple seed oil-based polyesteramide polyol- a precursor for layered double hydroxide (LDH)-modified polyurethane coatings

Polyesteramide polyol was synthesized by employing aminolysis with a base catalyst with custard apple seed oil as source material. It was afterward esterified with phthalic anhydride to form polyesteramide polyol. Polyurethane coatings are produced by combining polyesteramide polyols, which are synthesized, with hexamethylene diisocyanate trimer (HDI). The co-precipitation technique was used to synthesize a nickel-aluminum layered double hydroxide (Ni-Al LDH). Subsequently, the synthesized Ni-Al LDH was further modified by incorporating the corrosion inhibitor 2-mercaptobenzothiazole (MBT) into its interlayer space by the in-situ method. The synthesized Ni-Al LDH and Ni-Al-MBT LDH are then incorporated into the polyesteramide polyol to enhance the anti-corrosive properties of the polyurethane coatings. The synthesized diethanolamide, polyesteramide polyol, and LDH have been characterized using FTIR whereas SEM and XRD are specific to LDH analysis. EIS, DSC, TGA, salt spray, contact angle, and mechanical testing such as thickness, adhesion flexibility, scratch hardness, impact resistance, and pencil hardness are focused on coating evaluation. The incorporation of LDH led to a substantial enhancement in the coating's corrosion resistance, as evidenced by a decrease in corrosion. Incorporating LDH and MBT-LDH improved the scratch resistance of the coating by 1.5 kg compared to plain PU coating, whereas hardness properties also improved slightly. In anticorrosive analysis, it is observed that LDH and MBT-LDH show better anticorrosive performance as compared to plain PU coating.

V2O5-assembled NiAl-layered double hydroxide as high-performance electrode for asymmetric supercapacitor

V2O5-assembled NiAl-layered double hydroxide as high-performance electrode for asymmetric supercapacitor

Investigation of Ag nanoparticles decorated Ni-Al layered double hydroxide as a gas sensor

Chemiresistive gas sensors based on LDH structure were investigated for the detection of widely used volatile organic compounds (VOCs) including methanol, ethanol, and acetone at room temperature. In order to increase the surface active sites and subsequently improve the detection sensitivity of gas molecules, the use of Ag decoration method along with the creation of porosity on the surface of LDH structures were investigated. In this method, methanol solvent was used as a hole scavenger and UV radiation as a catalyst for binding Ag to the surface of LDH sheets. The microstructure and morphology of the composites were investigated by FESEM, HRTEM, EDS, EDS mapping, XRD, and MS analysis. The investigated parameters included relative humidity, calibration curve, repeatability, selectivity, and response/recovery times. According to the obtained results, the creations of surface corrosion by methanol and decorating the structure with Ag have both affected the sensitivity of the sensors. The pure Ni-Al LDH sensor has a response value of 6.8–250 ppm of ethanol. By increasing the specific surface area and creating LDH nanosheets, the response value can be increased up to 8.52. Also, the addition of Ag NP (Ni-Al LDH decorated with Ag NP) has increased the response up to 10.89. It was also observed that the response times in different modes have the least difference. At the end, the response mechanism was investigated based on the heterojunction theory.

Breakthrough Study of CO2 Adsorption and Regeneration Performance of Mn‐ and Ce‐Doped Ni–Al Layered Double Hydroxides Derived Mixed Oxides in Packed‐Bed Column

AbstractCarbon dioxide (CO2) capture is an important strategy to mitigate greenhouse gas emissions and reduce global warming effects. This study synthesizes two nanomaterials, Ce‐doped Ni–Al mixed metal oxide (CNAO) and Mn‐doped Ni–Al mixed metal oxide (MNAO), from Mn‐ and Ce‐doped Ni–Al‐layered double hydroxides using a co‐precipitation method followed by a calcination process. The materials are characterized using various techniques, such as High‐resolution transmission electron microscopy‐energy dispersive x‐ray spectroscopy/selected area electron dispersion (HRTEM‐EDS/SAED), X‐ray diffraction (XRD), x‐ray photoelectron spectroscopy (XPS), Brunauer‐Emmett‐Teller (BET), and attenuated total reflection Fourier transform infrared (ATR FT‐IR). The CO2 adsorption performance of the materials is evaluated using packed‐bed column experiments at the testing conditions of 13 vol% ± 1 vol% CO2 in N2 simulated flue gas, flow rate of 20 mL min−1, inlet pressure of 14.15 ± 0.1 psi, and temperature of 31 °C ± 2 °C. The results show that both CNAO and MNAO are promising nanomaterials for CO2 capture applications due to their high CO2 adsorption capacity and efficiency. CNAO has a higher saturation capacity of 11.4 mmol g−1 and a longer breakthrough time than MNAO, which has a saturation capacity of 10.0 mmol g−1. The doping of Ce and Mn enhances the CO2 adsorption capacity of the materials compared to the un‐doped Ni–Al mixed oxide. The mechanisms of CO2 adsorption are mainly linearly adsorbed CO2, bidentate, and monodentate or bulk carbonate formation, as revealed by ATR FT‐IR analysis. The regeneration performance results suggest that CNAO is more stable than MNAO under multiple regeneration cycles and more promising material for large‐scale CO2 capture applications.

Alkali-etched ultrathin NiAl-layered double hydroxides with rich vacancies for the sensitive electrochemical detection of dopamine

Defect engineering is an effective solution to improve the catalytic performance by liberating edge active sites. Herein, we report the synthesis of porous and ultrathin NiAl-layered double hydroxide nanosheets with rich defects (ELDHe) through the alkali etching followed by liquid delamination of the bulk NiAl-LDH. Etching and delamination actions introduce abundant defects and pores on the ultrathin LDH nanosheets, which can offer numerous edge sites, large specific surface area, and lots of vacancies. Consequently, the ELDHe modified glassy carbon electrode (ELDHe/GCE) realizes fast charge-transfer and mass-transfer on the electrode/electrolyte interface due to the more active centers and large surface area of ELDHe. The modified electrode presents excellent sensing performance toward dopamine. The chronoamperometric sensor achieves a large linear range of 0.05 ∼ 180 μM to dopamine with a detect limit of 6.1 nM. This sensor demonstrates good selectivity, reproducibility, and stability. The corresponding analytical method is successfully applied for the determination of dopamine in human urine samples.

Photocatalytic degradation of reactive dyes over Ni[sbnd]Al layered double hydroxide

Due to the uncontrolled discharge of textile effluents, the extent of reactive dyes in wastewater is rising. Due to their toxicity, efficient removal becomes quite essential. In this report, NiAl layered double hydroxide (LDH) has been prepared using the coprecipitation methodology for the photocatalytic degradation of reactive dyes. The as-prepared materials were characterized by different techniques, such as DRS, XRD, FESEM, HRTEM, and XPS etc. The XRD pattern of the LDH confirms the formation of the rhombohedral (R3m) phase. The FESEM analysis reveals the irregular hexagon-like shape of the prepared LDH. The NiAl LDH has 98(1) and 87(1)% photodegradation efficiencies towards the removal of reactive blue 19 and reactive Red 120, respectively. The control experiments in the presence of different scavengers confirm that hydroxyl radicals and superoxide anions participate in photocatalytic degradation. The HRMS studies confirm the formation of different smaller fragments, thereby providing a deeper insight into the photodegradation mechanism. Moreover, the demineralization efficiency (88.9%) is quite close to the degradation efficiency for reactive blue 19, signifying practically complete demineralization of the pollutants. The recyclability studies ascertain the high stability of the photocatalyst. Therefore, the as-prepared NiAl LDHs can be considered a promising photocatalyst for the removal of reactive dyes from wastewater.

Construction of MoS42− intercalated NiAl-layered double hydroxide by solvent-free method for promoting photocatalytic degradation of antibiotics: Synergistic effect of oxygen vacancies and electron-rich groups

MoS42− intercalated NiAl-layered double hydroxides (LDH) were prepared by solvent-free techniques, which possessed oxygen vacancies and efficient electron transfer channels. Oxygen vacancies were increased with increasing of the MoS42− intercalation amount. Through X-ray Photoelectron Spectroscopy (XPS), Electron Paramagnetic Resonance (EPR), Kelvin Probe Force Microscopy (KPFM), and Density Functional Theory (DFT), the presence of oxygen vacancies and electron transfer channels were confirmed. In the meantime, the formation mechanisms of electron transfer channels and the synergistic mechanisms involving oxygen vacancies and electron transfer channels were illustrated. Electrochemical characterization revealed that compared with LDH, the electron lifetime of LDH-WM-0.5 increased from 1.70 ns to 2.88 ns, and the recombination efficiency of electron holes was reduced by about 6 times. Degradation experiments demonstrated that the degradation rate of tetracycline by LDH-WM-0.5 increased from 19.0 % to 90.0 % in 3 h, representing a 4.5-fold improvement compared to LDH photocatalysts. This study contributed novel insights into developing advanced photocatalysts by strategically manipulating the presence of oxygen vacancies and constructing the electron transfer channels.

An S-scheme heterointerface-engineered high-performance ternary NiAl-LDH@TiO2/Ti3C2 MXene photocatalytic system for solar-powered CO2 reduction to produce energy-rich fuels

While there is much potential for photocatalytic CO2 reduction, poor light absorption and high recombination rates of photogenerated charges limit its effectiveness. To address these challenges, we systematically developed a heterointerface-engineered ternary hybrid photocatalyst comprising NiAl-layered double hydroxide (LDH), titanium dioxide (TiO2), and titanium carbide (Ti3C2) MXene via an in situ growth approach. As a result of the unique combination of these three components, the synthesized ternary NiAl-LDH@TiO2/Ti3C2 photocatalyst demonstrated broad light absorption spanning across the ultraviolet, visible, and near-infrared regions, as well as elevated CO2 adsorption capacity. In situ-irradiated X-ray photoelectron spectroscopy and electron paramagnetic resonance analyses provided compelling evidence for an unconventional S-scheme charge transfer mechanism in the ternary system that effectively separates the charges and suppresses recombination, allowing NiAl-LDH to maintain its strong reducing capacity and TiO2 to maintain its robust oxidizing capacity. Utilizing the complementary and synergistic properties of these three components (NiAl-LDH, TiO2, and Ti3C2), an optimized ternary NiAl-LDH@TiO2/Ti3C2 photocatalyst with 30 wt% Ti3C2 exhibited extraordinary solar-driven CO2 reduction performance with a remarkable 99 % CO selectivity against competitive H2 production and a high apparent quantum yield of 0.81 at 365 nm. Additionally, the ternary photocatalyst exhibited excellent stability, maintaining its performance capacity over multiple CO2 reduction cycles. This work provides a fresh perspective on designing and creating efficient ternary S-scheme photocatalytic systems for solar-driven CO2 reduction and highlights the potential for energy-rich fuel production.

Superior adsorptive removal of ciprofloxacin by graphene oxide modified Ni-Al layered double hydroxide composites

Pharmaceutical drug removal from industrial wastewater has become a major challenge in recent years. To address this concern, an eco-friendly, non-toxic, renewable, low-cost, and simple-to-synthesize catalyst called Ni-Al LDH (Layered Double Hydroxide) was synthesized using the co-precipitation method. LDH was further constructed with GO (Graphene Oxide) using the electro-self-assembly method for its effective performance in the removal of ciprofloxacin from wastewater. XRD, FESEM, EDX, Raman, FTIR, UV-Vis DRS, and BET analysis were used to characterize the as-prepared Ni-Al LDH and composites of GO@LDH. Using bare LDH and its composite with GO, several parameters such as adsorbent dosage, contact time, adsorbate concentration, and pH were optimized. GO(5)@LDH shows complete adsorption of 87.4% in 180 min for ciprofloxacin solution. The SBET for Ni-Al LDH, GO(1)@LDH, and GO(5)@LDH was determined to be in the order 3.5456 m2/g, 19.575 m2/g, and 22.5591 m2/g, suggesting that the surface area of the LDH increases upon GO loading. According to the calculation based on Langmuir isotherm, GO(5)@LDH (1968.5 mg/g) has a greater maximum adsorption capacity than Ni-Al LDH (332.2 mg/g). The kinetic analysis reveals that it adheres to a pseudo-second-order kinetic model. The catalyst was effectively employed for four repeating cycles with only a 10% decrease in removal rate, demonstrating that it can be easily regenerated. The morphology of the catalyst GO(5)@LDH remained the same before and after use, as seen by the XRD spectra, indicating the stability of the catalyst. As a result, LDH-GO composites are ideal catalysts for the treatment of ciprofloxacin wastes in the environment.

Treatment of Methylene Blue Using Ni-Al/Magnetite Biochar Layered Double Hydroxides Composite by Adsorption

Methylene blue dye is hard to degrade and requires treatment using Ni-Al Layered double hydroxides (LDHs) modified with magnetite biochar (MBC) to form Ni-Al/magnetite biochar composite in overcoming environmental pollution. Material attainment was identified by characterization using X-Ray Diffraction (XRD), Fourier Transform – Infra Red (FT-IR), Branuer Emmet Teller (BET), Scanning Electron Microscopy – Energy Dispersive X-Ray (SEM-EDX) and Vibration Sample Magnetometer (VSM). XRD characterization displays angle 2θ at 11°, 60° is a typical angle of LDH, and angles 22° and 35° of magnetite biochar. FT-IR characterization analysis at wavelength 1381 cm-1 for NO3- group and M-O group at wave number 700 cm-1. C-H group on biochar at 1404 cm-1 and wave number 586 cm-1 for Fe-O group. BET characterization analysis of Ni-Al/MBC has a large surface area and pore volume of 127.310 m²/g and 0.1950 cm³/g. SEM characterization analysis of Ni-Al/MBC has large, coarse pores and non-uniform shape, EDX data shows that there are forming elements such as Ni, Al from LDH and, Fe, C elements from magnetite biochar. pH, kinetics, isotherms, and thermodynamics become influential in adsorption processes. The adsorption capacity of the composite reaches 68.493 mg/g by following the Langmuir equation and adsorption kinetics refers to the Pseudo Second Order (PSO) equation. Adsorption continuity is spontaneous and endothermic. Ni-Al/MBC has stability in the process of adsorbent regeneration up to five adsorption cycles and, therefore can be used as a potential adsorbent in the treatment of methylene blue dye in aqueous environmental pollution. Copyright © 2023 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 

Flower-like Ni-Al/LDH synergistic polyaniline anchored to the carbon sphere surface to improve the fire performance of waterborne epoxy coatings

In this study, phytic acid -doped polyaniline (PPA) was loaded on the surface of carbon spheres, resulting in a classical C-N-P flame retardant system, that has a beneficial function for the formation of residual carbon. Subsequently, using this phosphorus-nitride carbon sphere (CS/PPA) as a carrier, flower-like Ni-Al-layered double hydroxide (Ni-Al/LDH) were uniformly grown on its surface, thus obtaining a novel nano-fire retardant with a graded structure to heighten the fire-resistant properties of aqueous epoxy resin. Importantly, the intervention of Ni-Al/LDH nanosheets not only imparts a gas-phase fire retardant function to the coating, but also the presence of Ni and Al bimetals can effectively catalyze the formation of more residual carbon in the combustion process. The highest residual carbon (30.7 %) in thermal weight loss experiments of the CS/PPA@Ni-Al/LDH/EP composite coating confirmed this view. Tests on the thermal insulation behavior of coatings illustrated that the backside temperature (168.8 °C) for CS/PPA@Ni-Al/LDH/EP was significantly smaller than that of other coatings, and that this optimum thermal shielding is inextricably linked to the high residual carbon and the residual metal oxides. Furthermore, the CS/PPA@Ni-Al/LDH/EP specimen shown the greatest expansion height (25.1 mm), expansion ratio (19.61) as well as the smallest smoke density rating (39.1 %), proving that its expansion property and smoke suppression were effectively improved. Moreover, the microstructure for the expanded carbon layer demonstrated that the CS/PPA@Ni-Al/LDH filled EP possessed a more complete and dense residual carbon after burning. Moreover, the high degree of graphitization of the residual carbon for CS/PPA@Ni-Al/LDH/EP determined its high thermal stability. The lowest cracked gas phase products and CO release of the CS/PPA@Ni-Al/LDH/EP composite coating during TG-IR testing confirmed its lowest fire toxicity. The development of such a composite flame retardant with a graded structure could help to advance the progress of waterborne intumescent fire coatings.

Performance and influencing mechanisms of magnetically separable Ni-M layered double hydroxides (M = Fe, Al) for catalytic ozonation

From a preliminary performance comparison of several layered double hydroxides (LDHs), magnetically separable Ni-M LDHs (M = Fe, Al) were synthesized and applied as efficient ozonation catalysts for degrading dye Rhodamine B (RhB). As proved by various characterizations, the micromorphology, nanostructure size, and porous feature of the synthesized Ni-M LDHs significantly varied with different metal components. Among them, Ni3-Fe LDH and Ni2-Al LDH possessed a relatively larger specific surface area to react with O3 interfacially, thereby exhibiting excellent catalytic ozonation performance. The RhB was almost completely degraded within 60 min, and the removal efficiencies of COD and TOC reached above 70% and 50%, respectively. The effects of catalyst dosage, initial dye concentration, solution pH, and coexisting inorganic anions on RhB degradation were studied systematically. ESR measurements and radical quenching experiments indicated that OH, O2−, and 1O2 are primary reactive oxygen species (ROS), while 1O2 induced the most dominant degradation contribution. According to the variations of ROS formation and material properties during the catalytic ozonation process, the possible reaction mechanisms were proposed. Moreover, the differences involved in the redox of multivalent metals and the transformation of surface hydroxyls over Ni-Fe and Ni-Al LDHs were further revealed.

Engineering a Ni-Al Brucite-Based Interface Layer with Regulated Zn2+ Flux for Highly Reversible Zn Metal Anodes.

Practical aqueous Zn-ion batteries are appealing for grid-scale energy storage with intrinsic safety and cost-effectiveness, yet their cycling stability and reversibility are limited by unwanted dendrite growth and water-induced erosions on Zn. Herein, a hydrophilic and Zn2+-conductive Ni-Al layered double hydroxide (NiAl-LDH) interphase layer is constructed on the surface of Zn, in which NiAl-LDH enables a more uniformly distributed Zn2+ concentration and interfacial electric field owing to its large internal Zn2+ channels and favorable charge redistribution effect. Consequently, the NiAl-LDH-integrated Zn anode achieves low voltage hysteresis and high reversibility of Zn plating/stripping with uniform underneath deposition behaviors. Remarkably, the resultant NiAl-2 LDH@Zn delivers superior cycling durability over 2800 h (∼4 months, 0.5 mA cm-2), realizes high reversibility with 99.4% average Coulombic efficiency over 1400 cycles, and confers stable operation of full Zn cells with high V2O5 mass loadings. This work offers a facile and instructive interface design approach for achieving highly stable Zn metal anodes.

Stacking Ni–Al and Co–Al Layered Double Hydroxide for High-Energy and High-Power Composite Electrodes

The requirement for high-power performance of secondary batteries suffering from inherent sluggish charge transfer kinetics is urgent for the expanding energy storage and conversion applications such as electric vehicles. A successful combination of high-power supercapacitors with high-energy secondary batteries in one energy storage device will meet the needs of both high power and energy density. We study the electrochemical behaviors of alternately stacked super-capacitive [Co4Al(OH)10]NO3 and [Ni4Al(OH)10]NO3 layered double hydroxide (LDH) electrodes. By cyclic voltammetry studies, the sandwich of [Co4Al(OH)10]NO3 lDH between [Ni4Al(OH)10]NO3 LDH and the Pt current collector results in the current amplification of the oxidation or reduction peaks to 4∼35 times. By galvanostatic charging/discharging, the 3-stacked Ni–Al|Co–Al|Ni–Al LDH electrode behaves better than the Co–Al|Ni–Al|Co–Al LDH electrode, exhibiting a maximal capacity, 338.1 mAh·g−1 under a current density of 1000 mA·g−1 and maintaining 288.6 mAh·g−1 within 400 cycles. It also has a much lower liquid-solid interface capacitor resistance and lower self-discharge. These results suggest that stacking in a suitable sequence contributes to high electrode performances, providing a strategy for producing energy storage and conversion devices. A synergetic charge transfer for the combination of Ni–Al and Co–Al LDH suggests that Co–Al LDH outstands as a bridge, accelerating the transfer of electrons.

2D/2D NiAl LDH integrated graphitic carbon nitride with robust interfacial contact for driving photocatalytic hydrogen production

Photocatalytic hydrogen production is promising for generating carbon-free energy through water splitting. Efficient photocatalytic materials with high photochemical efficiency are crucial for creating well-structured photocatalytic systems. Layered Double Hydroxides (LDHs) have gained significant scientific attention due to their unique electronic structure, compositional flexibility, and tunable band gap, which make them highly active for photocatalytic hydrogen evolution. However, the high surface energy of LDHs can lead to layer deactivation and reduce their efficiency as standalone photocatalysts. Herein, a novel design of two-dimensional (2D) g-C3N4 with 2D NiAl LDH to construct morphologically 2D/2D binary heterojunction composite with strong electrostatic interactions has been investigated. Different characterization techniques, such as XRD, FESEM, EDX, UV–Vis spectra, and PL were conducted to assess its photo-physical properties. The introduction of 15% NiAl LDH led to a significant increase in hydrogen production, reaching 28.13 µmol h−1, which is 3.75 and 9 times higher than pure g-C3N4 and NiAl LDH, respectively. The improved photocatalytic performance was attributed to the efficient charge transfer facilitated by the formation of Type-II heterojunction system. The interface junction observed in 2D/2D g-C3N4/NiAl LDH restricts charge recombination and extends its lifetime to carry out photocatalytic reactions. Furthermore, the effective integration of NiAl LDH onto g-C3N4 observed from FESEM and EDX prevents the deactivation of LDH nanoplates, supplying abundant reaction-active sites to expedite the photo-redox reaction. Significantly, the incorporation of transition metals, such as Ni and Al, into the LDH brucite layer enhances the optical properties, allowing for better utilization of light and further improving photocatalytic hydrogen production. This work provides valuable insights into the development of 2D/2D morphologically-engineered nanohybrids for driving photocatalytic hydrogen production.

The performance and mechanism for photocatalytic degradation of methylene blue catalyzed by ultrathin NiAl-layered double hydroxides

Ultrathin materials are widely used in various photocatalytic reactions due to their large specific surface area, multi-surface active sites, easy carrier separation and transport. In this work, ultrathin NiAl-layered double hydroxides (U-LDHs) nanosheets were prepared by a urea-assisted strategy for photocatalytic degradation of methylene blue. Atomic force microscopy (AFM) measurements show that the thickness of U-LDHs nanosheet is generally between 3 and 8 nm, with a wide pore size distribution and a high specific surface area (109 m2/g). U-LDHs nanosheets can remove 92.42% of methylene blue after 90 min light irradiation, which is nearly 40% higher than that of bulk NiAl-LDHs (B-LDHs). In addition, combined with photoelectric performance characterization and density functional theory calculation, it is confirmed that the U-LDHs nanosheets are much better to the separation and transfer of photogenerated carriers compared with the bulk LDHs. Besides, U-LDHs is conducive to adsorb oxygen to generate superoxide radicals, promoting the progress of photocatalytic reactions and significantly improving photodegradation performance.

An Efficient Intercalation Supramolecular Structure for Photocatalytic CO2 Reduction to Ethylene Under Visible Light

AbstractPhotocatalytic CO2 reduction (CO2PR) into multi‐carbon products (especially C2H4) is a highly attractive route for global carbon cycle, however, which is seriously limited by sluggish C‐C coupling kinetics and competitive hydrogen evolution reaction (HER) and so on. Herein, the fabrication of a novel supramolecular assembly of NiAl‐Fe‐TCPP is reported by intercalating iron porphyrin (Fe‐TCPP) into NiAl‐layered double hydroxide (NiAl‐LDH), and the resultant NiAl‐Fe‐TCPP exhibit superior catalytic performance on CO2PR to C2H4 under visible light irradiation in presence of photosensitizer. A high C2H4 selectivity up to 93.4% in the carbon‐containing products with the production rate as high as 24.7 µmol h−1 can be achieved over NiAl‐Fe‐TCPP. The ex/in situ X–ray absorption spectoscopy (XAS) indicates that the electron transfer between NiAl‐LDH and Fe‐TCPP can promote the generation of low‐valence of Fe sites, resulting in the efficient production of C2H4. The spin‐polarized density functional theory (DFT) calculations find that the synergistic mechanism that CO2 molecules are activated to CO on NiAl‐LDH and then spilled to Fe‐TCPP and coupled to COCHO#, which is further reduced to C2H4, are feasible in the perspective of Gibbs free energy. Moreover, the strong host‐guest interactions between NiAl‐LDH and Fe‐TCPP lead to the promoted photocatalytic activity and superior cycle stability.

Applications of Ni-Al Layered Double Hydroxide as Oxygen Evolution Reaction Catalysts Synthesized by Liquid Phase Deposition Process

Applications of Ni-Al Layered Double Hydroxide as Oxygen Evolution Reaction Catalysts Synthesized by Liquid Phase Deposition Process

Trace N-doped manganese dioxide cooperated with Ping-pong chrysanthemum-like NiAl-layered double hydroxide on cathode for improving bioelectrochemical performance of microbial fuel cell

Trace N-doped manganese dioxide (MnO2) nanoparticles were attached to NiAl-layered double hydroxide (LDH) nano sheets by a simple two-step hydrothermal reaction, and N-MnO2@NiAl-LDH was successfully prepared as cathode catalyst of microbial fuel cell (MFC). N-MnO2@NiAl-LDH was Ping-pong chrysanthemum-like structure formed by overlapping lamellar structures, with spherical MnO2 particles attached on. The unique Ping-pong chrysanthemum-like structure and pore size distribution provided large number of electrochemical active sites. The recombination of trace N and MnO2 reduced the charge transfer resistance, accelerated the electron transfer rate, and N-MnO2@NiAl-LDH showed high oxygen reduction reaction (ORR) capability. The maximum output power density of N-MnO2@NiAl-LDH-MFC was 698 mW/m2, about 4.59 times of NiAl-LDH (152.1 mW/m2). The maximum voltage was about 320 mV, and the stability was good for about 7 d. This would provide technical reference for the utilization of cathode catalyst for fuel cells.