3D Porous Network Research Articles

Interface engineering of Ni/NiO heterostructures with abundant catalytic active sites for enhanced methanol oxidation electrocatalysis

Designing efficient and stable non-noble metal electrocatalysts with good performance in reaction kinetics is desirable yet challenging for the study of methanol oxidation reaction (MOR). Herein, we have reported well-defined nanoscale nickel/nickel oxide (Ni/NiO) heterostructures supported by a three-dimensional (3D) porous graphene network (RG) via a delicate interface engineering technique. The as-prepared 3D Ni/NiO/RG composites achieve outstanding catalytic activity (79.5 mA cm−2/1262.1 mA mg−1) for MOR in alkaline solution, outperforming most reported non-precious catalysts. A combined experimental and computational investigation shows that such a good performance benefits from the specific Ni/NiO interface, which not only bears abundant accessible active sites but also improves the energetics of MOR. Moreover, this interface contributes to favorable kinetic and improved structural stability during electrocatalysis, ensuring superior catalytic performance after 1000 consecutive cyclic voltammetry tests for MOR. Our work demonstrates the potential of interface engineering in the rational design of efficient precious-metal-free electrocatalysts.

In-situ self-assembly robust defected graphene wrapped silicon/nanorod carbon for high-performance binder-free Li ion battery

• Utilization of evaporation-induced self-assembling method benefits to prepare the large scalable electrode film. • 3D conductive porous network provides voids for Si expansion and accelerates lithium ion transport. • The binder-free Si/NRC@DG stabilizes the capacity retention. • The Si/NRC@DG//LiFePO 4 full cell exhibits excellent electrochemical performance. High capacity silicon electrode with low cost is deemed as the promising anode material for the future Li-ion batteries with the replacement of graphite anode. In this work, robust defected graphene layers wrapped silicon/nanorod carbon (Si/NRC@DG) is synthesized through evaporation-induced self-assembly method for high lithium ion storage. Results show that the rapid conductive network formed by nanorods and defected graphene shorten the electron/lithium ion pathway to reach Si nanoparticles, enhancing the utilization. Meanwhile, the unique three-dimensional nano-architecture accommodates the large volumetric expansion of Si, immerses the electrolyte and facilitates efficient lithium ion diffusion. As a result, the so-synthesized Si/NRC@DG electrode exhibits a remarkable capacity of 669 mA h g −1 at 0.1 A g −1 after 100 cycles. Coupled with LiFePO 4 cathode, the assembled full cell is capable of offering an initial capacity of 126 mA h g −1 , providing opportunities for realizing high energy lithium ion batteries.

A novel hierarchical porous carbon-supported MnO2 nanofibers composite with three-dimensional interpenetrating network structure as a high-performance supercapacitor

For improving the conductivity of porous carbon and the utilizations of its pore structures, a hierarchical porous carbon (HPC) had been developed with highly fluffy three-dimensional (3D) continuous network structure. Using the HPC as a support, a novel MnO2@HPC composite with 3D interpenetrating network structure was prepared as electrode material of supercapacitor via simple hydrothermal method. When the hydrothermal reaction temperature was 100°C, the MnO2 nanofibers (∼5 nm) were uniformly grown on and within the fluffy 3D porous network of the HPC, forming a composite with interpenetrating network structure. The as-prepared composite (MnO2@HPC-100) exhibited the characteristics of both electric double-layer capacitance and pseudo-capacitance, which had a high specific capacity of 368 F g−1 at a current density of 0.5 A g−1 and 186 F g−1 at 10 A g−1 (50.5% retention). In addition, the asymmetric supercapacitor device was assembled with a relatively high energy density of 88.2 Wh Kg−1 at a power density of 162 W Kg−1. The device had a high capacity retention rate of 95% after 10000 cycles, and the coulomb efficiency was stable at 99.7%, showing the excellent stability of the composite. Therefore, the MnO2@HPC-100 composite has great application prospects in energy storage.

Series of TM-OFs as a Platform for Efficient Catalysis and Multifunctional Luminescence Sensing.

Three novel porous transition-metal-organic frameworks (TM-OFs), formulated as [Co3(DCPN)2(μ2-OH2)4(H2O)4](DMF)2 (1), [Cd3(DCPN)2(μ2-OH2)4(H2O)4](DMF)2 (2), and [CdK(DCPN)(DMA)] (3), have been successfully prepared via solvothermal conditions based on a 5-(3',6'-dicarboxylic phenyl) nicotinic carboxylic acid (H3DCPN) ligand. 1 and 2 both have the same porous 3D network structure with the point symbol of {410·614·84}·{45·6}2 based on trinuclear ({Co3} or {Cd3}) clusters, indicating a one-dimensional porous channel, and possess excellent water and thermal stability; 3 also displays a porous 3D network structure with a 4-connected sra topology based on the heteronuclear metal cluster {CdK}. Complex 1 can be used to load Pd nanoparticles (Pd NPs) via a wetness impregnation strategy to obtain Pd@1. The reduction of nitrophenols (2-NP, 3-NP, 4-NP) by Pd@1 in aqueous solution shows outstanding conversion, excellent rate constants (k), and remarkable cycling stability due to the synergistic effect of complex 1 and Pd NPs. Luminescence sensing tests confirmed that 2 is a reliable multifunctional chemical sensor with high selectivity and sensitivity for low concentrations of Fe3+, Cr2O72-, CPFX, and NFX. Specifically, 2 shows a fluorescence enhancement behavior toward fluoroquinolone antibiotics (CPFX and NFX), which has not been reported previously in the literature. Moreover, the rational mechanism of fluorescence sensing was also systematically investigated by various detection means and theoretical calculations.

Nanoparticle–Hydrogel Based Sensors: Synthesis and Applications

Hydrogels are hydrophilic three-dimensional (3D) porous polymer networks that can easily stabilize various nanoparticles. Loading noble metal nanoparticles into a 3D network of hydrogels can enhance the synergy of the components. It can also be modified to prepare intelligent materials that can recognize external stimuli. The combination of noble metal nanoparticles and hydrogels to produce modified or new composite materials has attracted considerable attention as to the use of these materials in sensors. However, there is limited review literature on nanoparticle–hydrogel-based sensors. This paper presents the detailed strategies of synthesis and design of the composites, and the latest applications of nanoparticle–hydrogel materials in the sensing field. Finally, the current challenges and future development directions of nanoparticle–hydrogel-based sensors are proposed.

Cotton-derived 3D carbon fiber aerogel to in situ support Bi2O3 nanoparticles as a separation-free photocatalyst for antibiotic removal

Because of abundant oxygen-based groups, natural cotton is adopted as the precursor to in situ fabricate a three-dimensional (3D) Bi2O3-supported carbon fiber aerogel (Bi2O3/CF). The calcination temperature plays an important role in the crystal composition of Bi species and the specific surface area of the aerogel. When the calcination temperature is 800 °C, the Bi2O3/CF product exhibits the highest tetracycline (TC) removal efficiency, including large adsorbability and superior photocatalytic activity. Furthermore, its 3D porous network architecture provides a multidimensional open framework for the free mobility of solution and rapid diffusion of reactants and products. In the flowing system, the 3D Bi2O3/CF aerogel can implement the continuous and stable elimination of pollutants for a long time, and it does not require any separation operation. Consequently, the 3D Bi2O3/CF aerogel is expected as a promising functional material to massively remove organic pollutants from industrial wastewater.

Hierarchically Porous Three-Dimensional (3D) Carbon Nanorod Networks with a High Content of FeNx Sites for Efficient Oxygen Reduction Reaction.

Efficient, durable, and inexpensive electrocatalysts are recommendable for accelerating the kinetics of oxygen reduction reaction and achieving high performance. Herein, with predesigned hierarchically porous silica nanorods as a hard template, hierarchically macro-bimodal meso/microporous 3D carbon interwoven nanorod networks containing a high content of single-atom FeNx species (Fe/RNC) were prepared by melting of precursors and confined pyrolysis within the pores of the hard template. What distinguishes the use of silica nanorods as a hard template is that it not only provides a porous texture for confined pyrolysis of the precursors but also the interwoven texture of the nanorods gives rise to a macroporous mesh-like morphology. Benefiting from the ultrahigh iron content (5.69 wt %) of the FeNx sites, a 3D porous network configuration with high accessibility of active centers, as well as a high specific surface area of 793 m2g-1, the as-prepared Fe/RNC exhibited superior activity and durability for ORR and zinc-air batteries. For comparison, the catalyst Fe/NC-MCM, which was prepared with a similar procedure but with unimodal mesoporous silica MCM-41 nanoparticles as the hard template, possesses a less porous structure and active accessibility and thus exhibits inferior ORR activity. This work provides an effective design/nanoengineering for electrocatalysts in ORR and zinc-air batteries and will inspire more research on accessibility of active sites in non-noble carbon-based electrocatalysts.

3D porous carbon conductive network with highly dispersed Fe–N x sites catalysts for oxygen reduction reaction

Intrinsic activity and reactive numbers are considered two important factors in oxygen reduction reaction (ORR) catalysts. Herein, we report the rational design and synthesis of a strongly coupled hybrid material comprising of FeZn nanoparticles (FeZn NPs) supported by a three-dimensional carbon conductive network (FeZn NPs@3D-CN) for increased ORR performance. Fe–N–C sites can offer high intrinsic activity owing to the unique bonding and oxygen vacancies, and the carbon conductive network facilitating the exposure to active sites, and increasing electron transport. Because of the synergetic effect of the conductive networks containing Fe–N–C and polyaniline, the catalysts exhibited ORR activity in an alkaline medium via a four-electron transfer process. FeZn NPs@3D-CN exhibited outstanding performance with a limited current density (6.2 mA cm−2), the Tafel slope (81.19 mV dec−1), and stability (23 mV negative shift after 2000 cycles), which were superior to those of 20% Pt/C (5.7 mA cm−2, 75.1 mV dec−1, 36 mV negative shift after 2000 cycles). This research highlights the effect of conductive networks expanding pathways and reducing the resistance of mass transport, which is a facile method to generate superior ORR electrocatalysts.

Improved recurrent generative model for reconstructing large-size porous media from two-dimensional images.

Modeling the three-dimensional (3D) structure from a given 2D image is of great importance for analyzing and studying the physical properties of porous media. As an intractable inverse problem, many methods have been developed to address this fundamental problems over the past decades. Among many methods, the deep learning-(DL) based methods show great advantages in terms of accuracy, diversity, and efficiency. Usually, the 3D reconstruction from the 2D slice with a larger field-of-view is more conducive to simulate and analyze the physical properties of porous media accurately. However, due to the limitation of reconstruction ability, the reconstruction size of most widely used generative adversarial network-based model is constrained to 64^{3} or 128^{3}. Recently, a 3D porous media recurrent neural network based method (namely, 3D-PMRNN) (namely 3D-PMRNN) has been proposed to improve the reconstruction ability, and thus the reconstruction size is expanded to 256^{3}. Nevertheless, in order to train these models, the existed DL-based methods need to down-sample the original computed tomography (CT) image first so that the convolutional kernel can capture the morphological features of training images. Thus, the detailed information of the original CT image will be lost. Besides, the 3D reconstruction from a optical thin sectionis not available because of the large size of the cutting slice. In this paper, we proposed an improved recurrent generative model to further enhance the reconstruction ability (512^{3}). Benefiting from the RNN-based architecture, the proposed model requires only one 3D training sample at least and generates the 3D structures layer by layer. There are three more improvements: First, a hybrid receptive field for the kernel of convolutional neural network is adopted. Second, an attention-based module is merged into the proposed model. Finally, a useful sectionloss is proposed to enhance the continuity along the Z direction. Three experiments are carried out to verify the effectiveness of the proposed model. Experimental results indicate the good reconstruction ability of proposed model in terms of accuracy, diversity, and generalization. And the effectiveness of sectionloss is also proved from the perspective of visual inspection and statistical comparison.

3D porous carbon network-reinforced defective CoFeOx@C as a high-rate electrode for lithium-ion batteries

Integrating metal oxides with three-dimensional (3D) porous carbon is extremely desirable for improving the capacity and cyclability of lithium-ion batteries (LIBs). Herein 3D porous carbon network (3DPCN)-reinforced composite electrodes were developed by integrating biomass (i.e., agaric)-derived 3DPCN and Prussian blue analogue (PBA)-generated carbon-coated metal oxides (CoFeOx@C). To achieve an integrated structure, PBA precursors were directly deposited and grown on 3DPCN (PBA/3DPCN), and then, PBA/3DPCN was subjected to low-temperature oxidation in air and thermal treatment in Ar to yield double carbon-modified metal oxides (CoFeOx@C/C). The interconnected CoFeOx@C/C electrode, as an advanced anode of LIBs, delivers excellent capacity and cyclability, with typical specific capacities of 1043.4 mAh g−1 at 0.2 A g−1 and 483.2 mAh g−1 at as high as 5.0 A g−1 after 120 cycles. This superior electrochemical performance originates from the interconnected structure of 3DPCN, the finely regulated composition of nanosized CoFeOx@C, and the tight contact and synergistic effect between 3DPCN and CoFeOx@C. The 3DPCN not only provides a void space for buffering the volume change of CoFeOx@C but also acts as a framework for improving the conductivity of the entire electrode, while compositionally optimized defective CoFeOx@C contributes the majority of the specific capacity. Our work paves the way to overcome the drawbacks (e.g., low electronic conductivity, self-aggregation, and low rate capability) of metal oxides as electrodes of LIBs.

CoS nanoparticle encapsulated S-doped carbon nanofiber/nanotube hybrid grown on exfoliated graphite for long-lifespan and high-rate potassium ion batteries

Exfoliated graphite (EG) as important matrix material for potassium-ion batteries (PIBs) suffers from its inherent low surface activity, which results in poor interactions with active matter (e.g. metal sulfides) and undesired initial capacity decay of the EG-based electrodes. To address these issues, in this study, an attempt for EG’ surface engineering has been carried out through a stepwise gas-phase strategy. A S-doped carbon nanofiber/nanotube (CNF/CNT) hybrid was in-situ introduced on the surface of EG to form a novel micro-/nano- multiscale matrix structure. CoS nanoparticles are encapsulated in the inner of CNFs and CNTs. The special core–shell configuration not only prevents the aggregation of CoS during the sulfidation process, but also confines the active nanoparticles to avoid pulverization and maintains stable integrated electrode structure. Moreover, the couple effect between the active site-rich nature of CNFs and the high conductivity of CNTs as well as the formation of 3D porous network contribute to substantially elevated reversible capacity (411 mAh g−1), excellent initial cycling stability and rate capability (184 mAh g−1 at 2.0 A g−1). The effective surface modification strategy dominated by rational hybridization of CNFs and CNTs provides a new avenue for the development of high-performance electrode materials in PIB applications.

Cyanogel‐Induced PdCu Alloy with Pd‐Enriched Surface for Formic Acid Oxidation and Oxygen Reduction

Pd‐based catalysts with preferred morphologies and compositions are of great significance for boosting oxygen reduction reaction (ORR) and formic acid oxidation reaction (FAOR) performance, but the development of facile preparation methods is challenging. Therefore, an unconventional strategy is proposed to synthesize palladium‐copper cyanogel (Cux[Pd(CN)4]y·aH2O) and subsequently induce the formation of PdCu alloy nanocorals (ANCs), which has the advantages of being simple, green, and efficient. The synthesized PdCu ANCs consist of a 3D porous network structure and Pd‐enriched surface, which is beneficial to exposing more accessible active sites, accelerating mass/electron transfer rate, and strengthening chemical stability. By virtue of these merits, the PdCu ANCs exhibit superior activity and stability in both FAOR and ORR. Remarkably, the mass activity of PdCu ANCs catalyst in FAOR reaches 554.53 mA mgPd−1, with a 4.8‐fold enhancement compared to commercial Pd black. And the half‐wave potential of 0.861 V of PdCu ANCs catalyst in ORR surpasses the values of commercial Pd black and Pt black catalysts.

Ambient-Dried, Ultra-high Strength, Low Thermal Conductivity, High Char Residual Rate F-type Polybenzoxazine Aerogel.

The effect of the curing temperature (Tc) on the properties of PBO aerogel was investigated in this paper. The compressive strength of PBO aerogel prepared was much higher than that of PBO aerogel of the same density in other kinds of literature. With the robust F-type polybenzoxazine (PBO) aerogels with ultra-high Young’s modulus (733.7 MPa at 0.48 g/cm3 and 1070 MPa at 0.57 g/cm3), excellent properties were obtained through a facile and scalable room-temperature HCl-catalyzed sol–gel method, followed by the ambient pressure drying technique. It is found that Tc plays a vital role in the polymerization process and the evolution of the microstructure of the 3D porous PBO network, where the necks between the nanoparticles become thick and strong when Tc is up to 150 °C, resulting in a pearl necklace-to-worm transformation in the micro-structure and significant growth in mechanical properties, but if Tc is higher than 180 °C, the pore volume and specific surface area will decrease sharply. Moreover, all synthetic PBO aerogels here possessed inherent flame retardancy and a high residual char rate in the volume density (0.32–0.57 g/cm3). These properties make the F-type PBO aerogels a candidate material in aerospace applications or other fields.

Three-dimensional nickel and copper-based foam-in-foam architecture as an electrode for efficient water electrolysis

A cost-effective and benign electrocatalyst designed by facile synthetic routes with noteworthy electrochemical performance is widely desired for water electrolysis. Noble-metal based electrocatalyst are known to have better catalytic performance. However, the arduous obstacle in its commercialization towards H2 fuel generation, high cost and their limited availability restricts its high-scale and industrial use. Therefore, there is an urgent demand for an alternative electrocatalyst towards water splitting which is not only highly efficient and cost-effective but earth-abundant as well. Straight growth/synthesis of the nanostructured electrocatalyst on the current collector or conducting substrate directly boosts up the reaction kinetics, activity and most importantly the stability of the catalyst. The electrocatalyst takes the benefits of the conducting substrate in terms of synergistic effect between active material and the substrate, active surface area, electrons rich environment as well as conductivity. 3D nickel foam (Nif) and copper foam (Cuf) have been explored and proved to be efficient conducting substrate due to their hierarchical 3D porous network which provides conducting channel for easy and fast ion transport during water electrolysis. In the current article, we are reporting an effectual foam in foam architecture, where copper foam was electrochemically grown on nickel foam (Nif@Cuf) under controlled and optimized conditions. This bimetallic foam serves a dual role of conductive substrate as well as active material. Here, the electrochemical activity of as synthesized Nif@Cuf were extensively explored to check and analyse its performance towards water splitting. The substrate was found to hold excellent electrocatalytic performance and attained a potential of 1.6 V to drive a current density of 10 mA cm−2 with an admirable stability. Thus, this simple yet effective approach of catalyst designing could be explored more for direct growth of nanostructured electrocatalyst applied for future renewable energy technology.

Hierarchical N-Doped porous 3D network electrode with enhanced capacitive deionization performance

Capacitive deionization (CDI) has emerged as a promising method of desalination owing to its outstanding regeneration efficiency, low energy consumption, and without secondary contamination. The electrosorption capacity is largely determined by the electrode material. Nevertheless, the bottlenecks of present carbon-based CDI electrode materials are their limited desalination capability and single pore channel, which are unfavorable for salt ion diffusion and access to the internal space. Herein, we synthesized nitrogen-doped porous carbon (NPC) and performed a facile activation to obtain hierarchical porous carbon (KNPC) for CDI desalination. The optimized KNPC showed a remarkable desalination performance of 28.40 mg/g in 500 mg/L NaCl solution, with an exceptional regeneration performance of 94.44% after 15 consecutive cycles. The enhanced CDI performance could be attributed to the following aspects: (1) KNPC was introduced plenty of microporous and mesoporous structures, which provides convenient transport channels and accelerated salt ion transport. (2) The enlarged specific surface area and pore volume provide sufficient adsorption sites for salt ions. (3) The modified KNPC exhibited excellent electrochemical properties and wettability, consisting of higher specific capacitance, decreased internal resistance, and ultra-high hydrophilicity. (4) KOH activation promoted the capacitive contribution of the KNPC electrode, thus improving its CDI performance.

Hydrophilic antifouling 3D porous MXene/holey graphene nanocomposites for electrochemical determination of dopamine

Dopamine (DA) detection is essential for diagnosis and evaluation of diseases such as Parkinson’s, Alzheimer and schizophrenia. However, conventional electrochemical sensors are vulnerable to biofouling in complex biological fluids, which leads to significant decrease in sensor performance. Ti3C2Tx MXene, a novel 2D material with excellent conductivity and hydrophilicity, is a potential antifouling material for electrodes. But oxidation can strongly influence the performance of MXene. In this work, an antifouling electrochemical sensor for DA detection was fabricated by combining MXene and holey graphene (HG). Multilayer MXene (M−MXene) and single-layer MXene (S-MXene) were combined with HG to form a 3D porous network. HG not only prevented the restacking of MXene but it also improved the stability of MXene. Owing to the excellent conductivity and large surface area, S-MXene/HG modified electrode had a fast electron transfer and excellent electrocatalytic activity for DA compared with M−MXene/HG. Furthermore, S-MXene/HG possessed higher surface hydrophilicity and enhanced biofouling resistance than M−MXene/HG and HG modified electrode. S-MXene sensor displayed excellent analytical performance for DA and antifouling ability in complex fluids. It offers new promising possibilities for its clinical application.

In situ preparation of NiCoFe-LDH nanoflowers on carbon cloth toward simultaneous detecting hydroquinone and catechol

Herein, for the first time, a self-supported electrode for simultaneous determination of hydroquinone (HQ) and catechol (CA) was synthesized by loading NiCoFe-layered double hydroxide nanoflowers on hydrophilic carbon cloth (NiCoFe-LDH NFs/CC) with a simple hydrothermal method. By combining the advantages of NiCoFe-LDH NFs with hydrophilic carbon cloth such as good conductivity, 3D porous network structure, high electrocatalytic activity, and fast electron transport, the proposed NiCoFe-LDH NFs/CC electrode dispalyed good electrochemical activity for detecting HQ and CA. The binder-free and free-standing electrode based on NiCoFe-LDH NFs/CC possessed good linear range (5–200 μM), low determination limit (0.15 μM and 0.11 μM), and strong selectivity. Furthermore, it also showed good electrochemical stability without obvious change in ten days. More importantly, as-prepared electrode could be used as an efficient electrochemical sensor to determine HQ and CA content in actual samples with good recovery rate, revealing its feasibility in potential application.

Built‐In Stable Lithiophilic Sites in 3D Current Collectors for Dendrite Free Li Metal Electrode

Stable lithiophilic sites in 3D current collectors are the key to guiding the uniform Li deposition and thus suppressing the Li dendrite growth, but such sites created by the conventional surface decoration method are easy to be consumed along with cycling. In this work, carbon fiber (CF)-based 3D porous networks with built-in lithiophilic sites that are stable upon cycling are demonstrated. Such heterostructured architecture is constructed by the introduction of zeolitic imidazolate framework-8-based nanoparticles during the formation of the 3D fibrous carbonaceous network and the following annealing. The introduced Zn species are found to be re-distributed along the entire individual CF in the 3D network, and function as lithiophilic sites that favor the homogenous lithium nucleation and growth. The 3D network also presents a multi-scale porous structure that improves the space utilization of the host. The corresponding symmetric cells adopting such 3D anode demonstrate excellent cycling performance, especially at a high rate (300 cycles at 10mAcm-2 with a capacity of 5mAhcm-2 ). A full cell with LiFePO4 cathode shows a capacity retention of 98% after cycling at 1C for 300 cycles. This method provides an effective design strategy for 3D hosting electrodes in dendrite-free alkali metal anode applications.

Three‐Dimensional Porous Low‐Defect Carbon Nanotube and Graphene Network Supported Rh Nanocrystals as Efficient Methanol Oxidation Electrocatalysts

AbstractWith the rapid economic development and urgent environmental demands, the direct methanol fuel cell (DMFC) as one of environmental‐friendly energy‐conversion systems has attracted wide attention in the world, while the insufficient activity and low structural stability of the anode Pt/carbon catalyst largely deteriorate its overall performance. Herein, we report a facile and cost‐effective bottom‐up method to the fabrication of rhodium nanocrystals supported by three‐dimensional (3D) porous hybrid networks constructed from low‐defect carbon nanotubes and reduced graphene oxide (Rh/LCNT‐RGO) as Pt‐alternative electrocatalysts for DMFC. Such a structural design gives the resultant Rh/LCNT‐RGO hybrid a series of fantastic architectural advantages, such as the large specific surface area of 3D interconnected graphene configuration, high electrical conductivity of low‐defect carbon nanotubes, and abundant catalytically active sites of well‐dispersive Rh nanocrystals. As a consequence, the Rh/LCNT‐RGO hybrid displays unusual catalytic abilities towards the methanol electrooxidation, including a large electrochemically active surface area of 123.8 m2 g−1, a high mass activity of 1228.5 mA mg−1, strong poison tolerance, and long lifespan, far surpassing those of reference Rh/carbon black, Rh/acid‐treated CNT, and Rh/RGO catalysts.

Superlative photoelectrochemical properties of 3D MgCr-LDH nanoparticles influencing towards photoinduced water splitting reactions

In the present work, we report the synthesis of single system three-dimensional (3D) open porous structure of MgCr-LDH nanoparticles in a substrate-free path by using one-step formamide assisted hydrothermal reaction followed by visible light irradiation for significant photoelectrochemical (PEC) properties that manifest towards photocatalytic H2 and O2 production. The as-prepared nanostructured materials were characterized by various physico-chemical characterization techniques. Moreover, this unique synthetic approach produces 3D open porous network structure of MgCr-LDH nanoparticles, which were formed by stacking of numerous 2D nanosheets, for effective light harvestation, easy electronic channelization and unveil superlative PEC properties, including high current density (6.9 mA/cm2), small Tafel slope of 82 mV/decade, smallest arc of the Nyquist plot (59.1 Ω cm−2) and photostability of 6000 s for boosting water splitting activity. In addition, such perfectly self-stacked 2D nanosheets in 3D MgCr-LDH possess more surface active defect sites as enriched 50% oxygen vacancy resulting a good contact surface within the structure for effective light absorption along with easy electron and hole separation, which facilitates the adsorption of protons and intermediate for water oxidation. Additionally, the Cr3+ as dopant pull up the electrons from water oxidation intermediates, thereby displaying superior photocatalytic H2 and O2 production activity of 1315 μmol/h and 579 μmol/h, respectively. Therefore, the open 3D morphological aspects of MgCr-LDH nanoparticles with porous network structure and high surface area possess more surface defect sites for electron channelization and identified as distinct novel features of this kind of materials for triggering significant PEC properties, along with robustly enhance the photocatalytic water splitting performances.