Energy Conversion Applications Research Articles

Impact of aliovalent La-doping on zinc oxide – A wurtzite piezoelectric

The development of high-performance low-cost electroactive films for energy conversion and electronic device applications is a key goal of current advanced materials and condensed matter physics research. Here, using solution-based scalable chemical spray pyrolysis, high-quality electroactive lanthanum-doped zinc oxide (i.e., Zn1-xLaxO) thin films are grown on silicon substrates, and the impact of aliovalent lanthanum doping is investigated using a suite of microstructural, optical and nanoscale scanning probe microscopy techniques. The synthesized polycrystalline thin films show hexagonal wurtzite crystal structure with an increased unit cell volume, crystallite size, and conductivity with lanthanum doping up to 4 at.% beyond which the thin films (6 at.%), however, exhibit a change in dominant crystalline orientation from (101) to (002) plane. Concurrently, at this optimal dopant concentration of 4–6 at.%, the electromechanical performance is enhanced by about 20 %, and polarity-dependent nanoscale electronic transport behaviour is revealed. Our study, therefore, provides key insights into the impact of the rare earth aliovalent lanthanum dopant on the electroactive and electronic properties of low-cost, functional thin films for sustainable energy and sensing applications.

Electronic and optical properties of As/Bi2Se3 van der Waals heterostructure: Ab initio insights

In this study, based on the first-principles calculations, we theoretically studied the electronic and optical properties of two dimensional (2D) As/Bi2Se3 van der Waals (vdW) heterostructure. The results show that all the materials exhibit semiconducting behavior with calculated band gaps of Eg = 1.71, 1.0, and 1.65 eV without spin-orbit coupling (SOC), for As monolayer, Bi2Se3 monolayer, and As/Bi2Se3 heterostructure respectively. Notably, the As/Bi2Se3 heterostructure demonstrates a type-II band alignment, facilitating the effective spatial separation of photogenerated carriers. This characteristic offers exciting opportunities for applications in efficient optoelectronic devices, photocatalysis, and solar energy conversion. The optical properties studies show that the heterostructure exhibits significant light absorption across the visible to ultraviolet light spectrum, making it a promising candidate for a wide array of optoelectronic devices.

Sabatier principle guiding the design of cathode catalysts for Li-CO2 batteries

The Sabatier principle has been widely used for designing electrocatalysts for energy conversion applications, but it is rarely mentioned in the research of cathode catalyst of Li-CO2 batteries. In our work, the “volcanic” relationship between the catalytic activity and the adsorption energy of the catalyst to the intermediates is first demonstrated based on the first-principles calculation, which meets the Sabatier principle and can be used to design the cathode catalysts. The increases in the number of nitrogen-vacancy in WN shift the d-band center and increase the interaction with the reactants. The catalytic activity increases first and then decreases with the increase of adsorption energy, which was proved in the experiment. The optimal catalyst for moderate adsorption of intermediate makes the thin Li2CO3 distribute evenly. It exhibits a median voltage difference of 0.68 V and an energy efficiency of 84.33% at 20 μA cm−2 with a limited capacity of 200 μA h cm−2.

D-band center modulation of supported Ru on phosphorous doped black TiO2 for efficient hydrogen generation

Metal oxide has been considered as promising support to regulate the active microenvironment of noble metals to promote the catalytic performance, but they suffer from unsatisfactory electrical resistance and poor stability. Herein, ultrafast quasi-solid microwave (60 s) is employed to achieve phosphorous-doped black TiO2 supported Ru (Ru/P-TiO2) with d-band center modulation to optimize the reaction kinetics of hydrogen evolution reaction (HER). The as-synthesized Ru/P-TiO2 exhibits extraordinary HER activities in alkaline fresehwater/seawater electrolytes with overpotential of 43 mV to reach 10 mA cm−2 coupled with satisfactory stability. Experiment and density functional theory (DFT) calculation clarify that the achieved Ru/P-TiO2 owns optimal d-band center for H* adsorption. Moreover, the phosphorous doping enhanced the electronic interactions between Ru and oxygen vacancy-enriched TiO2 to optimize the reaction kinetics and enhance the stability. This work provides promising strategy to modulate the metal oxide matrix for designing novel catalysts on energy conversion and storage applications.

Highly Stable MOF-Type Lead Halide Luminescent Ferroelectrics.

Lead halide molecular ferroelectrics represent an important class of luminescent ferroelectrics, distinguished by their high chemical and structural tunability, excellent processability and distinctive luminescent characteristics. However, their inherent instability, prone to decomposition upon exposure to moisture and light, hinders their broader ferroelectric applications. Herein, for the first time, we present a series of isoreticular metal-organic framework (MOF)-type lead halide luminescent ferroelectrics, demonstrating exceptional robustness under ambient conditions for at least 15 months and even when subjected to aqueous boiling conditions. Unlike conventional metal-oxo secondary building units (SBUs) in MOFs adopting highly centrosymmetric structure with limited structural distortion, our lead halide-based MOFs occupy structurally deformable [Pb2X]+ (X=Cl-/Br-/I-) SBUs that facilitate a c-axis-biased displacement of Pb2+ centers and substantially contribute to thermoinducible structural transformation. Importantly, this class of MOF-type lead halide ferroelectrics undergo ferroelectric-to-paraelectric phase transitions with remarkably high Curie temperature of up to 505 K, superior to most of molecular ferroelectrics. Moreover, the covalent bonding between phosphorescent organic component and the light-harvesting inorganic component achieves efficient spin-orbit coupling and intersystem crossing, resulting in long-lived afterglow emission. The compelling combination of high stability, ferroelectricity and afterglow emission exhibited by lead halide MOFs opens up many potential opportunities in energy-conversion applications.

MXenes as Electrocatalysts for Energy Conversion Applications: Advances and Prospects

Hydrogen as a potential future energy source provides a number of benefits in terms of sustainability, high energy density, and zero emissions. The production of hydrogen via water splitting is regarded as the cleanest and sustainable process. In contrast, fossil fuel combustion causes significant environmental problems through the production and release of secondary gases such as NOx, SO2, and CO2. It is vital to focus on reducing these harmful gases. CO2, a major pollutant produced by the combustion of fossil fuels and various human activities, plays a central role in the greenhouse effect and contributes to global warming. It is therefore imperative to actively eliminate and mitigate CO2 levels to preserve the global environment. MXenes and MXene‐based catalysts exhibit both outstanding hydrogen evolution reaction (HER) performance and CO2 reduction. In this review, recent progress is systematically examined and discussed in the preparation and utilization of MXenes as catalysts for HER and carbon dioxide reduction reaction (CO2RR). The discussion begins with a concise overview of the fabrication and characteristics of MXenes, followed by a comprehensive exploration of their efficacy as catalysts for HER and CO2RR.

Ultra-broadband absorber based on algorithmic optimization of MgF2–Fe stacked structure

Broadband absorbers possess a wide array of potential applications, including electromagnetic cloaking, solar energy harvesting, and solar power generation. However, achieving excellent ultra-broadband absorption with plasma-metal materials remains challenging due to their inherently narrow bandwidth. To tackle this issue, we propose an ultra-broadband absorber, free from lithography, composed of a multilayer stack of magnesium-iron fluoride (MgF2–Fe). In this study, we optimized the structural parameters of the absorber using a particle swarm optimization algorithm to achieve theoretically optimal absorptivity. Numerical simulations revealed that the absorber achieved an impressive theoretical average absorption of 98.4% across a broad wavelength range from ultraviolet to near-infrared (321–1800 nm). Importantly, it exhibited stable absorption performance at large incidence angles (0–70°), while maintaining high absorption efficiency. Furthermore, it demonstrated polarization independence at perpendicular incidence angles. Subsequently, experimental preparations and tests were conducted on absorber samples to evaluate their solar energy absorption capacity. Both experimental and theoretical comparisons underscored the promising potential of this structure for applications in solar energy collection, conversion, and solar power generation.

Empirical heat transfer correlations of high-pressure transcritical fluids at low Reynolds numbers

Empirical heat transfer correlations serve as indispensable tools for predicting and optimizing the thermal performance of a wide range of engineering devices, like for example in energy conversion and propulsion applications. Although a remarkable number of correlations exist for systems at low (atmospheric) pressures, accurately quantifying heat transfer under high-pressure transcritical conditions poses a notable challenge, especially at low Reynolds numbers due to the scarcity of correlations available in the literature. This difficulty has prompted the widespread use of general empirical correlations, which are inadequate for such flow conditions, and hold significant implications, for instance, in fields like microfluidics technology. In this regard, the aim of this study is to develop novel heat transfer correlations tailored for high-pressure transcritical fluids at relatively low Reynolds numbers. These correlations are derived from a dataset of 18 direct numerical simulations of carbon dioxide confined between differentially heated walls, which induce a transcritical trajectory through the pseudo-boiling region. The correlations are developed for both the cold liquid-like and hot gas-like regions, resulting in a total of 6 correlations that encompass the laminar, transitional, and turbulent flow regimes. In particular, as a function of Reynolds, Prandtl, Eckert and Mach numbers, the proposed empirical correlations provide accurate estimations with relative errors below 8%, which significantly surpass existing literature correlations.

Thermoelectric performance of Ag2GeX3 (X = S, Se, Te) with intrinsically low lattice thermal conductivity: A first principles study

Low lattice thermal conductivity is one of the key factor for excellent thermoelectric performance of materials. In this work, we have systematically studied the thermoelectric properties of Ag2GeX3 (X = S, Se, Te) by first-principles calculations in combination with Boltzmann transport theory. In terms of phonon transmission performance, due to the low frequency of acoustic phonons, strong coupling between low-frequency optical phonons and acoustic phonons, and relatively strong anharmonicity, Ag2GeX3 (X = S, Se, Te) exhibits extremely low lattice thermal conductivity of 0.30 Wm−1K−1, 0.28 Wm−1K−1 and 0.65 Wm−1K−1 at room temperature, respectively. At the same time, Ag2GeX3 (X = S, Se, Te) also exhibits good electrical transport performance. The appropriate band gap and high slope of electronic density of states (DOS) near the Fermi level result in a large Seebeck coefficient of the materials. As a result, the optimal ZT values of p(n)-type Ag2GeX3 (X = S, Se, Te) are 1.4(1.2), 2.2(0.7), and 0.9(0.7) at 800 K, respectively. These results demonstrate outstanding thermoelectric performance of Ag2GeSe3 for energy conversion applications.

Nanoscale Surface and Bulk Electronic Properties of Ti3C2Tx MXene Unraveled by Multimodal X-Ray Spectromicroscopy.

2D layered materials, such as transition metal carbides or nitrides, known as MXenes, offer an ideal platform to investigate charge transfer processes in confined environment, relevant for energy conversion and storage applications. Their rich surface chemistry plays an essential role in the pseudocapacitive behavior of MXenes. However, the local distribution of surface functional groups over single flakes and within few- or multilayered flakes remains unclear. In this work, scanning X-ray microscopy (SXM) is introduced with simultaneous transmission and electron yield detection, enabling multimodal nanoscale chemical imaging with bulk and surface sensitivity, respectively, of individual MXene flakes. The Ti chemical bonding environment is found to significantly vary between few-layered hydrofluoric acid-etched Ti3C2Tx MXenes and multilayered molten salt (MS)-etched Ti3C2Tx MXenes. Postmortem analysis of MS-etched Ti3C2Tx electrodes cycled in a Li-ion battery further illustrates that simultaneous bulk and surface chemical imaging using SXM offers a method well adapted to the characterization of the electrode-electrolyte interactions at the nanoscale.

Photoexcited charge carrier dynamics and electronic properties of two-dimensional MXene, Nb2CT x

Two-dimensional, 2D, niobium carbide MXene, Nb2CT x , has attracted attention due to its extraordinarily high photothermal conversion efficiency that has applications ranging from medicine, for tumor ablation, to solar energy conversion. Here, we characterize its electronic properties and investigate the ultrafast dynamics of its photoexcitations with a goal of shedding light onto the origins of its unique properties. Through density functional theory, DFT, calculations, we find that Nb2CT x is metallic, with a small but finite DOS at the Fermi level for all experimentally relevant terminations that can be achieved using HF or molten salt etching of the parent MAX phase, including –OH, –O, –F, –Cl, –Br, –I. In agreement with this prediction, THz spectroscopy reveals an intrinsic long-range conductivity of ∼60 Ω−1 cm−1, with significant charge carrier localization and a charge carrier density (∼1020 cm−3) comparable to Mo-based MXenes. Excitation with 800 nm pulses results in a rapid enhancement in photoconductivity, which decays to less than 25% of its peak value within several picoseconds, underlying efficient photothermal conversion. At the same time, a small fraction of photoinjected excess carriers persists for hundreds of picoseconds, and can potentially be utilized in photocatalysis or other energy conversion applications.

Palladium Metallene‐Based Electrocatalysts for Energy Conversion Applications

AbstractPalladium (Pd)‐based catalysts are considered compelling alternatives to platinum (Pt)‐based counterparts in various electrocatalytic reactions. Recently, Pd metallene‐based nanomaterials have emerged as innovative materials for electrocatalysis, demonstrating unique functional properties and exceptional catalytic activity. This review aims to discuss recent research progress on Pd metallene‐based electrocatalysts for energy conversion applications, providing an overview of their design strategies and pivotal advantages. Seven pivotal construction strategies for Pd metallene‐based electrocatalysts, including defect engineering, interface engineering, strain effect, phase engineering, alloying effect, and doping effect, are meticulously introduced and comprehensively discussed, highlighting their critical roles in modulating the electronic structure and coordination environment. Finally, the current challenges and perspectives on the future directions of Pd metallene‐based electrocatalysts are provided.

Polyethylene assisted CNTs in-situ growth on Fe-Mn-O to boost the electrochemical and electrocatalytic performance

Efficient reuse of plastic wastes is turning waste into treasure, and crucial to green and sustainable development. Herein, a flexible strategy was proposed to fabricate the composite of transition metal and carbon nanotubes (CNTs), i.e., polyethylene (PE) assisted CNTs in-situ growth on Fe-Mn-O. Mn-O and Fe-Mn-O was sequentially prepared via the coprecipitation method and impregnation method, and used for CNTs synthesis from PE via the thermo-catalytic process. It was found that PE facilitated CNTs in-situ growth on Fe-Mn-O, and CNTs yield was 456.1 mg/g, which was mostly in a hollow cylindrical structure with a heterogenous metal-particle. Based on the metal yarmulke structure, the in-situ growth of CNTs on Fe-Mn-O seemed to follow the tip growth mode. Compared with Fe-Mn-O, the in-situ growth of CNTs significantly improved the electrochemical and electrocatalytic performance. Fe-Mn-O/CNTs composite exhibited a specific capacitance of 135 F/g at 0.3 A/g in 1 M Na2SO4 electrolyte solution and an oxygen evolution reaction (OER) overpotential of 306 mV at 50 mA/cm2 in 1 M KOH electrolyte solution, which was 75 F/g higher and 59 mV lower than that of Fe-Mn-O (60 F/g and 365 mV), respectively. It was deduced that the in-situ growth of CNTs effectively reduced the electrochemical impedance and improved the charge transport, and thus promoted the electrochemical and electrocatalytic performance of Fe-Mn-based materials. This work may provide a new direction for the resource of plastic wastes and the preparation of advanced transition metal/CNTs composites in the energy conversion and storage application.

Single atoms/metal nanoparticles-decorated hollow carbon spheres as oxygen reduction catalyst for zinc-air batteries

Non-platinum electrocatalyst development for improving the oxygen reduction reaction (ORR) is critical in electrochemical energy conversion applications such as zinc-air batteries (ZABs). Herein, we developed dual Fe-Co single atoms and Co nanoparticles embedded N-doped hollow carbon (Fe-Co/N-HCS-x) catalysts via the carbonization of polypyrrole (PPy)@zeolitic imidazolate framework (ZIF) core–shell particles, with various PPy concentrations. PPy serves as a secondary nitrogen source that enhances nitrogen amount and promotes metal dispersion to increase active sites density. The Fe-Co/N-HCS-x catalysts with optimized PPy concentration control demonstrated improved ORR performance in alkaline media, with a half-wave potential (E1/2) of 0.921 V and an onset potential (Eonset) of 1.019 V. Fe-Co/N-HCS-x also exhibited high ZABs performance, with a power density of 244.6 mW cm−2 and an operating time of more than 100 h. Our research contributes to the development of optimized active sites for ORR, which can be applied to new electrochemical storage and conversion systems.

Enhanced methanol electrooxidation catalysis via dual modulation of PtCu alloy and oxygen vacancies

Achieved by introducing defect sites, enhances both the catalytic activity and stability of catalysts. This is crucial for advancing key applications in energy conversion and environmental protection. Here, we introduce a novel Pt-Cu@CeO2/MWCNTs electrocatalyst prepared by dual modulation of the oxygen vacancy anchoring point and the center of the alloying d-band. This catalyst significantly boosts the rate of methanol oxidation. The Pt-Cu@CeO2/MWCNTs catalyst demonstrates a mass activity 3.7 times higher than that of commercial Pt/C, along with exceptional durability. The electron transfer between the PtCu alloy and the oxygen vacancies effectively modulates the d-band center of Pt, leading to a “volcano” relationship between the catalyst’s mass activity and the d-band center. This study advances the development of methanol electrooxidation catalysts by introducing a novel “double enhancement effect” model.

Pyrochlore-type lanthanide titanates and zirconates: Synthesis, structural peculiarities, and properties

This contribution provides a thorough examination of the structural characteristics of pyrochlore-type lanthanide titanates and zirconates Ln2Ti2O7 and Ln2Zr2O7, across various length scales. This paper also examines their processing, interesting physical properties (electrical, magnetic, and thermal characteristics), and responses to high pressure and ion irradiation. Brief sections on the elemental oxides' crystal chemistry, pertinent phase diagrams, and energetics of defect formation are also provided. Pyrochlore-type Ln2Ti2O7 and Ln2Zr2O7 stand out as truly multifunctional materials. Moreover, they have emerged as fascinating materials due to magnetic geometrical frustration, arising from the ordering of magnetic Ln3+ and non-magnetic Ti4+ (or Zr4+) cations into separate, interpenetrating lattices of corner-sharing tetrahedra. This results in a diverse array of exotic magnetic ground states, such as spin-ice (e.g., Dy2Ti2O7 or Ho2Ti2O7) or quantum spin ice (e.g., Tb2Ti2O7), observed at both low and room temperatures. They also exhibit varied electrical and electrochemical characteristics. Some members such as Gd2Zr2O7, function as fast ion conductors with a conductivity (σ) of ≈10−2 S·cm−1 at 800 °C and activation energy (Ea) ranging from 0.85 to 1.52 eV, depending on the degree of structural disorder. Others, such as Gd2TiMoO7, are mixed ionic-electronic conductors with σ ≈ 25 S·cm−1 at 1000 °C, making them promising candidate materials for applications in energy conversion and storage devices and oxygen separation membranes. Their exceptionally low thermal conductivity (e.g., κ ∼ 1.1–1.7 W·m−1·K−1 between 700 and 1200 °C for Ln2Zr2O7), close to the glass-like lower limit of highly disordered solids, positions them as valuable materials for thermal barrier coatings. They can also effectively accommodate actinides (e.g., Pu, Np, Cm, Am) in solid solutions and sustain prolonged exposure to radiation due to alpha-decay events, while preserving the integrity of the periodic atomic structure. Proposed as major components in actinide-bearing ceramics, they contribute to the long-term immobilization and disposal of long-lived waste radionuclides from nuclear programs. Some of these properties are displayed simultaneously, opening avenues for new applications. Despite the wealth of data available in the literature, this review highlights the need for a better understanding of order/disorder processes in pyrochlore-type materials and the influence of the structural length scale on their physical and chemical properties. Recent experimental evidence has revealed that pyrochlore short-range structure is far more complex than originally thought. Moreover, pyrochlore local structure is now believed to include short-range, lower symmetry, ordered domains, such as the orthorhombic weberite-type of structure. Notably, short- and long-range structures appear decoupled across different length scales and temperature regimes, and these differences persist even in well-ordered samples. We believe that the pyrochlore structure offers a unique opportunity for examining the interplay between chemical composition, defect chemistry, and properties. In Memoriam: Rodney C. Ewing, Fondly Remembered.

Fabrication of Gd doped Fe-Co/Cu electrodes for magnetic field assisted water splitting applications

We investigated the magnetic characteristics of Gadolinium-doped Iron-Cobalt/Copper (Gd-Fe-Co/Cu) electrodeposited thin films at various Gd concentrations over 20 min at room temperature and pH 3. The structure and composition of metal ions are confirmed by X-ray diffraction and the EDAX spectrum. SEM examination of the microstructures revealed a variety of morphologies, including spherical ball-like crystallites and one-dimensional spike-like crystallites. The varied Gd ion concentrations had an effect on the Gd-Fe-Co/Cu thin films, which exhibited soft magnetic properties. The introduction of Gd3+ into the system has demonstrated ferromagnetic properties at room temperature, as verified through VSM analysis. Elevating the Gd concentration in the thin film led to an augmentation in saturation magnetization and a reduction in coercivity. Selected samples were subjected to BET and CV studies. CV studies confirmed the capacitive behaviours of the sample. The best magnetic behaviour was seen for the Gd concentration of 0.05 M, suggesting that these films might be suitable candidates for application in energy storage and conversion. Further, the best sample was taken for water splitting studies and showcased excellent HER performance under magnetic field.

Synergy between gelatin hydrogels and electrodes for adjustable and thermally stable ionic thermoelectric supercapacitors

Gelatin-based ionic hydrogels are flexible, bio-compatible, and abundant materials, showing immense potential as quasi-solid-state electrolytes in energy conversion and storage applications. Recent studies highlighted the critical synergy between hydrogel electrolytes and electrodes on the thermopower and energy density in emerging ionic thermoelectric (i-TE) devices. In this work, the significant impact from electrodes to the thermoelectric response of gelatin hydrogels is explored and explained at the molecular level. A universal negative offset in the thermopower is observed when substituting the conventional Cu foil by carbon-based paper (CBP) electrodes. This is attributed to the electrolyte infiltration and strong cation restriction on the CBP electrodes, which facilitates anion thermodiffusion. The thermopowers of Gelatin-CsCl change from p- (0.1–0.5 mV K−1) to n-type (up to −2.89 ± 0.34 mV K−1) and remain thermally stable at a large temperature difference of −36.8 K. The power factor and average power density in the ionic thermoelectric supercapacitors (ITESCs) made from Gelatin-0.02 M CsCl and CBP electrodes reach 2.13 ± 0.50 μW m−1 K−2 and 145.37 μW m−2 at a small temperature difference of −7.7 K. Furthermore, the highest normalized instantaneous power density achieved during the quasi-continuous charge–discharge cycles is 39.42 μW m−2 K−2, among the best ITESCs. This work provides fundamental insights into the previously overlooked synergy between gelatin hydrogels and electrodes for adjustable and thermally stable i-TE conversion and energy storage devices.

Rational development of semiconductor-based electrocatalyst and its electrochemical activity for ethanol oxidation as an assisted reaction for water splitting

Implementation of semiconductor-based nanocomposites for emerging technologies has been gaining exponential interest due to their unique physical, chemical, and electrochemical properties. Nonetheless, challenges still exist in developing active and stable materials to produce high-value-added electrocatalytic platforms for energy conversion applications. This work proposes the synthesis of a composite material comprising ZnO and Cu2O modified with SrSO4 by using the fast and versatile microwave heating process as feasible electrocatalysts for ethanol-assisted water electrolysis. The obtained composite was characterized by X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy coupled with Energy Dispersive Spectroscopy (FESEM-EDS), Thermogravimetric Analysis (TGA), Fourier Transform Infrared (FTIR), and Raman spectroscopies. Electrochemical features were assessed by cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The XRD results clearly show that composite material has reflections corresponding to the ZnO, Cu2O, and SrSO4, while the FESEM-EDS analysis reveals the presence of the desired chemical elements. The fabricated ZnO–SrSO4–Cu2O composite was electrochemically characterized to determine its potential as a catalyst for the ethanol oxidation reaction (EOR). The results unveil that the electroactivity of the composite is mainly attributed to the presence of Cu species and the synergistic effect of ZnO and SrSO4 compounds. In this way, this work proposes a novel via of fabricating active semiconductive electrocatalysts for the hybrid water electrolysis in the presence of the EOR. However, we believe this kind of material can be adopted in other applications such as sensors and energy storage devices.

Magnetic Hyperporous Elastic Material with Excellent Fatigue Resistance and Oil Retention for Oil-Water Separation.

Oily wastewater has caused serious threats to the environment; thus, high-performance absorbing materials for effective oil-water separation technology have attracted increasing attention. Herein, we develop a magnetic, hydrophobic, and lipophilic hyperporous elastic material (HEM) templated by high internal phase emulsions (HIPE), in which free-radical polymerization of butyl acrylate (BA) and divinylbenzene (DVB) is employed in the presence of poly(dimethylsiloxane) (PDMS), lecithin surfactant, and modified Fe3O4 nanoparticles. The adoption of the emulsion template with nanoparticles as both stabilizers and cross-linkers endows the HEM with biomimetic hierarchical open-cell micropores and elastic cross-linked networks, generating an oil absorbent with outstanding mechanical stability. Compressive fatigue resistance of the HEM is demonstrated to endure 2000 mechanical cycles without plastic deformation or strength degradation. By exploiting the synergistic effect of hierarchical structures and low-surface-energy components, the resulting HEM also possesses excellent and robust hydrophobicity (water contact angle of 164°) and good oil absorption capacity, in which Fe3O4 nanoparticles lead to convenient magnetically controlled oil recyclability as well. Notably, the unique biomimetic microporous structure demonstrates superior oil retention capacity (>95% at 1000 rpm and >60% at 10,000 rpm) over the state-of-the-art porous materials for a diverse variety of oils to reduce the risk of secondary oil leakage, along with good recoverability by squeezing owing to the excellent compression resilience. These excellent performances of our HEM provide broad prospects for practical applications in oil-water separation, energy conversion, and smart soft robotics.