Macropore Walls Research Articles

Hierarchically Structured, Highly Porous Nickel Synthesized in Sintering–Evaporation Process from a Metal Nanopowder and a Space Holder

Permeable (~70% porosity) nickel with a pronounced hierarchical structure was synthesized by powder metallurgy methods in sintering–evaporation process from a nickel nanopowder and an ammonium bicarbonate micropowder as a space holder. The obtained porous nickel contained pores of three spatial scales: macropores (30–50 μm in size), their connecting windows (5–10 μm), and interparticle micropores (less than 1 μm) in the walls of macropores. The produced material is characterized by a network of interpenetrating macropores and by a developed surface of their walls consisting of several layers of sintered nickel nanoparticles.

La-Doped mesoporous calcium silicate/chitosan scaffolds for bone tissue engineering.

Trace rare earth elements such as lanthanum (La) regulated effectively bone tissue performances; however, the underlying mechanism remains unknown. In order to accelerate bone defects especially in patients with osteoporosis or other metabolic diseases, we firstly constructed lanthanum-doped mesoporous calcium silicate/chitosan (La-MCS/CTS) scaffolds by freeze-drying technology. During the freeze-drying procedure, three-dimensional macropores were produced within the La-MCS/CTS scaffolds by using ice crystals as templates, and the La-MCS nanoparticles were distributed on the macropore walls. The hierarchically porous structures and biocompatible components contributed to the adhesion, spreading and proliferation of rat bone marrow-derived mesenchymal stem cells (rBMSCs), and accelerated the in-growth of new bone tissues. Particularly, the La3+ ions in the bone scaffolds remarkably induced the osteogenic differentiation of rBMSCs via the activation of the TGF signal pathway. A critical-sized calvarial-defect rat model further revealed that the La-MCS/CTS scaffolds significantly promoted new bone regeneration as compared with pure MCS/CTS scaffolds. In conclusion, the La-MCS/CTS scaffold showed the prominent ability in osteogenesis and bone regeneration, which showed its application potential for bone defect therapy.

Robust hierarchically interconnected porous carbons derived from discarded Rhus typhina fruits for ultrahigh capacitive performance supercapacitors

An efficient and economic approach for sustainable production of hierarchically interconnected porous carbons are designed and fabricated through the pyrolysis of Rhus typhina fruits and followed by KOH activation to create micropores or mesopores on the nano-sheet wall of macropores. The related N-doped carbon consists of a plenty of micropores and owns high specific surface area (up to 2675 m2 g−1), resulting in high performances for supercapacitors, such as ultrahigh specific capacitance (568 F g−1 at 1 A g−1), remarkable rate capability (310 F g−1 at 20 A g−1, 282 F g−1 at even 30 A g−1 current density) and good long-term stability (capacitance retention of 99% after 10000 cycles at 30 A g−1) in 1 mol L−1 H2SO4. Moreover, the carbon derived from Rhus typhina fruits demonstrates 474 F g−1 at 1 A g−1, 281 F g−1 at 30 A g−1, and capacitance retention of 92% after 10000 cycles at 30 A g−1 in 6 mol L−1 KOH electrolyte. This novel and sustainable biomass-derived carbon material holds a bright future for fabricating high energy supercapacitors.

The efficacy of good practice to prevent long-term leaching losses of phosphorus from an irrigated dairy farm

Phosphorus (P) can be leached from intensive land uses, including grazed dairy farming. There is some evidence to suggest that P-leaching can enrich groundwater, especially where fertiliser or farm dairy effluent P (FDE) is applied to soils of low sorption capacity. We measured P fractions in leachate at 70 cm depth from two soils of low-P sorption capacity in an intensively grazed dairy farm, one a free-draining shallow soil and another a deep and moderately well-drained soil. As per industry good practice, the soils were maintained at an agronomic optimum and received P as either fertiliser or a lower rate of fertiliser plus FDE, applied according to regional rules and industry guidelines to avoid the FDE ponding on the soil surface and leaching to depth. Our hypothesis was that rules and guidelines were not sufficient to prevent P losses, especially in the free-draining soil. In response to annual applications of 40 kg P ha−1 yr−1 as fertiliser or 30 kg P ha−1 yr−1 as fertiliser and 10 kg P ha−1 yr−1 as FDE, dissolved and particulate P concentrations increased annually 4 to 7%. Mean total P load over the 14-yr period of measurement (2001–2015) from the FDE-treated, free-draining shallow soil was 1.46 kg ha−1 yr−1, much greater than the same soil without FDE (0.25 kg ha−1 yr−1) or the moderately well-drained soil with or without FDE applied (0.12 kg ha−1 yr−1, for both treatments). Leaching losses were attributed to a combination of high hydraulic conductivity enhanced by the presence of macropores and the increasing P saturation of macropore walls. An enrichment in dissolved reactive P was also detected in a well intercepting groundwater at 10-m depth. However, the source of the enrichment was unclear. These data suggest that despite following industry good practice, regional rules and industry guidelines significant P losses may occur when FDE is applied to soil at rates designed to maintain soil Olsen P in an agronomically optimal concentration. It is unclear if applying less FDE at lower rate, would decrease P losses. Therefore, less P must be applied, made less available for loss, or P-rich FDE not applied to this freely draining shallow stony soil (or similar soils) under irrigation.

Cerium-doped whitlockite nanohybrid scaffolds promote new bone regeneration via SMAD signaling pathway

The development of nanoscience, nanohybrid technology and molecular biology provide an important strategy in the construction of novel bone scaffolds. Nanosized whitlockite (WH) and trace cerium (Ce) element exist widely in human bones; however their positive functions on bone cells/tissues still remain unknown. Inspired by the chemical components and nanostructures of bones, Ce-doped WH/chitosan (Ce-WH/CS) nanohybrid scaffolds were developed for new bone regeneration. The Ce-WH/CS scaffolds exhibited interconnected macropores with sizes of ∼300 μm, which facilitated cell adhesion and bone tissue in-growth. Ce-WH nanoparticles with sizes of 10–50 nm were dispersed on macroporous walls. The WH/CS scaffolds with or without doping Ce3+ ions had non-toxicity to human adipose derived stromal cell (hADSCs). Interestingly, the Ce3+ ions in the Ce-WH/CS scaffolds significantly improved osteogenic activity via activated SMAD signaling pathway, and up-regulated the expression of osteogenic-related genes including osteocalcin (OCN), osterix (OSX) and collagen 1A1 (COL1A1). Rat cranial defect models further demonstrated that Ce-WH/CS scaffolds remarkably accelerated material biodegradation and bone tissue growth compared to WH/CS scaffolds. The exciting finding revealed the positive functions of Ce-WH nanoparticles on bone tissues, and provided a promising platform for new bone regeneration.

Modification of Ordered Macroporous Silica by a Functional Polymer Layer and Immobilization of Glucoamylase on the Macropore Walls

Modification of Ordered Macroporous Silica by a Functional Polymer Layer and Immobilization of Glucoamylase on the Macropore Walls

Pickering Emulsion Stabilized by Microporous Organic Polymer Particles for the Fabrication of a Hierarchically Porous Monolith.

A hierarchically porous monolith comprising the melamine-based microporous organic polymer (MOP) particles was prepared by the Pickering emulsion templating method. The MOP particles were synthesized by polycondensation of melamine and terephthaldicarboxaldehyde. Because of the balanced presence of hydrophilic nitrogen containing groups and hydrophobic benzene rings, the MOP particles showed good amphiphilicity. A Pickering emulsion was prepared, where cyclohexane droplets with an average size of about 25 μm were stabilized by the MOP particles (3.4 wt %) in an aqueous continuous phase. The cyclohexane internal phase fraction was slightly higher than 60%. The emulsion showed no phase separation even after two weeks. The Pickering emulsion containing a small amount of polyvinyl alcohol (1 wt %) in a continuous phase as a reinforcement was used as a template for the fabrication of a monolith of the MOP particles. The Pickering emulsion was freeze-dried to produce a hierarchically porous monolith. The MOP monolith possessed macropores templated by the oil droplets and micro- and mesopores in the MOP particles that constituted the macropore walls. The MOP monolith exhibited a high dye absorption ability in a solution of RhB in chloroform and a good absorption capacity for nonpolar organic solvents. After the absorption, the monolith could be regenerated by solvent exchange with cyclohexane and subsequent freeze-drying.

Icariin loaded-hollow bioglass/chitosan therapeutic scaffolds promote osteogenic differentiation and bone regeneration

The design and fabrication of therapeutic bone scaffolds that combine bioactive materials with osteoinductive drugs is a promising strategy for bone regeneration. Herein, we firstly developed icariin loaded-hollow bioglass/chitosan (ICA/HBG/CS) therapeutic scaffolds to treat critical-sized bone defects. The HBG/CS hybrid scaffolds possessed three-dimensional (3D) interconnected macropores with sizes of approximately 200 μm, which not only promoted the adhesion and spreading of stem cells, but also accelerated the in-growth of bone tissues. The HBG microspheres with hollow core and mesoporous shell were uniformly distributed on the macropore walls. The ICA drugs could be controllably released from the therapeutic scaffolds because of the hierarchically porous structures and hydrogen-bonding interactions. The as-released ICA drugs from the scaffolds remarkably up-regulated the expression levels of osteogenic-related genes (COL1 and RUNX2) and osteogenic-related proteins (ALP and p-Smad1/5). The micro-CT images, Masson’s trichrome staining and double fluorochrome labelling results revealed that the ICA/HBG/CS therapeutic scaffolds remarkably accelerated the formation of new bone tissues compared to the scaffolds without ICA drugs. Hence, the ICA/HBG/CS therapeutic scaffolds including bioactive materials and osteogenic drugs can serve as a kind of novel and promising bone materials for enhanced osteogenic differentiation and new bone regeneration.

Three-dimensionally ordered macro/mesoporous TiO2 matrix to immobilize sulfur for high performance lithium/sulfur batteries

A three-dimensionally (3D) ordered macro-/mesoporous TiO2 (3DOM-mTiO2) was synthesized via a simple solvothermal process. 3DOM-mTiO2 was used as a sulfur carrier for cathode materials in a lithium–sulfur (Li–S) battery. The orderly interconnected macro and mesopores structure within the macropore walls yield a large pore volume and high specific surface area in 3DOM-mTiO2, which improved the sulfur loading capacity of the material. The S/TiO2 composite was synthesized as a cathode material for lithium/sulfur battery, which initially produced a high capacity of 1089 mAh g−1 and retained a value of 703 mAh g−1 after 200 cycles. An initial current rate of 0.2 C was used, which was further increased up to 2.5 C when a reversible capacity of 651 mAh g−1 was obtained. The excellent electrochemical performance can be attributed to the 3D ordered macro-/mesoporous structure of TiO2, which physically confines the soluble lithium polysulfides and diminishes the sulfur volume expansion upon cycling. In addition, the strong electrostatic attraction between the Ti–O bond and polysulfide stimulates the performance via stronger adsorption of the electrochemical reaction products.

Formation of microporous silicon in straight macropore on n-type silicon under front side illumination

To find a sacrificed layer on walls of silicon macropore, the microporous silicon (MPS) was formed on the wall of straight silicon macropore (SSMP) by electrochemical etching on n-type silicon. The front side illumination was used to control the thickness of MPS on SSMP wall. The experiment showed that the thickness of MPS was more easily controlled by changing the illumination than the applied electric field and etching electrolyte. So the injected carrier model (ICM) was proposed for deducing an experimental equation between the illuminance and MPS thickness. Light attenuation in silicon was confirmed as the major cause of MPS formation in SSMP. ICM model could be used to predict the porous structure etched by front side illumination on n-type silicon.

Synthesis of hierarchically macro-mesoporous CoTiO3 with improved gas sensing properties

Hierarchically porous CoTiO3 powders with interconnected framework composed of nanoparticles as high performance gas sensing materials for ethanol were prepared by sol-gel method with C4H11NO2 (DEA) as the chelating agent. A characteristic of hierarchical pore size distribution with both mesopores ranging from about 2 to 10 nm and macropores approximately from 0.15 to 3 μm can be found within the porous CoTiO3 powders prepared at a molar ratio of DEA to Ti and Co of 1.6 : 1 : 1. The formation of macropores is mainly depending on the pore characteristics of gel skeletons before calcination, while the mesopores within macropore walls are generated after calcination. The sensing performances of porous cobalt titanate with different pore structure characteristics were compared based on the fabricated gas sensors. The hierarchically porous CoTiO3 powders with a specific surface area of 47.04 m2 g−1 demonstrate the maximum response (71.5) towards 100 ppm ethanol at 420 °C. The corresponding response and recovery time are about 15 and 22 s, respectively.

ZnO nanoparticles encapsulated in three dimensional ordered macro-/mesoporous carbon as high-performance anode for lithium-ion battery

Herein, we report a three-dimensionally (3D) ordered macro-/mesoporous carbon (3DOM-mC) as the ZnO nanoparticles support for the anode material in lithium-ion batteries (LIBs). The 3DOM-mC is synthesized by the typical dual-templating method that combines the hard-templating (silica opal as template) and soft-templating techniques using resol (phenol/formaldehyde) as the carbon source. The prepared 3DOM-mC material having ordered interconnected macropores and mesopores is then applied to support ZnO nanoparticles to form the ZnO/3DOM-mC composite via a simple in situ solution growth approach. In the ZnO/3DOM-mC composite, the ZnO nanoparticles (∼4.5 nm) are evenly dispersed on the macropore walls of the 3DOM-mC. The ZnO/3DOM-mC composite (40 wt% ZnO loading) anode shows an enhanced LIB performance delivering a specific capacity of 973.3 mAh g−1 after 100 cycles and 1396.6 mAh g−1 after 300 cycles at 0.1 C. This good electrochemical performance of the ZnO/3DOM-mC is ascribed to the ordered interconnected macropores of the 3DOM-mC that can provide the rapid diffusion of Li ions and electrolytes and the ordered mesopores that can buffer the volume expansion of ZnO during the cycling operation.

In Situ Generated Dual-Template Method for Fe/N/S Co-Doped Hierarchically Porous Honeycomb Carbon for High-Performance Oxygen Reduction.

Heteroatoms doping is able to produce catalytic sites in carbon materials for oxygen reduction reaction (ORR); while hierarchically porous structure is necessary for efficient exposure and accessibility of the usually limited catalytic sites in such activated carbon catalysts. This work reports an in situ generated dual-template method to synthesize the Fe/N/S co-doped hierarchically porous carbon (FeNS/HPC), with NaCl crystallites formed during the precursor lyophilization process as the primary template to generate ∼500 nm macropores with ultrathin graphene-like carbon-layer walls, and Fe3O4 nanoparticles formed during the high-temperature carbonization process as the secondary template to produce mesopores on the walls of macropores. As well as the coexistence of graphitic-N, pyridinic-N, and thiophene-S which are beneficial to ORR, the as prepared FeNS/HPC possesses a highly graphitized and interconnected hierarchical porous structure, giving a specific surface area as high as 938 m2 g-1. As a consequence, it exhibits excellent four-electron oxygen reduction performance in both alkaline and acid electrolytes. The in situ generation and facile solution removal make the present template method a promising way for scale-up preparation of active porous carbon materials for various applications.

Activated Biomass-derived Graphene-based Carbons for Supercapacitors with High Energy and Power Density

Here, we present a facile and low-cost method to produce hierarchically porous graphene-based carbons from a biomass source. Three-dimensional (3D) graphene-based carbons were produced through continuous sequential steps such as the formation and transformation of glucose-based polymers into 3D foam-like structures and their subsequent carbonization to form the corresponding macroporous carbons with thin graphene-based carbon walls of macropores and intersectional carbon skeletons. Physical and chemical activation was then performed on this carbon to create micro- and meso-pores, thereby producing hierarchically porous biomass-derived graphene-based carbons with a high Brunauer-Emmett-Teller specific surface area of 3,657 m2 g−1. Owing to its exceptionally high surface area, interconnected hierarchical pore networks, and a high degree of graphitization, this carbon exhibited a high specific capacitance of 175 F g−1 in ionic liquid electrolyte. A supercapacitor constructed with this carbon yielded a maximum energy density of 74 Wh kg−1 and a maximum power density of 408 kW kg−1, based on the total mass of electrodes, which is comparable to those of the state-of-the-art graphene-based carbons. This approach holds promise for the low-cost and readily scalable production of high performance electrode materials for supercapacitors.

Three-dimensional analysis of micro- and nanostructure of biomaterials and cells by method of scanning probe nanotomography

Aim: to perform a three-dimensional analysis of micro- and nanosctucture and quantitative morphological parameters of alginate spherical microcarriers and porous regenerated silk macrocarriers modifi ed by microparticles of decellularized rat liver matrix and human hepatoma HepG2 cells adhered to micro- and macro carriers.Materials and methods. Three-dimensional porous matrices made from regenerated silk by salt leaching technique and alginate spherical microcarriers fabricated by encapsulation were vitalized by human hepatome HepG2 cells. Study of three-dimensional structure of cells and micro- and macro carriers was carried out at –120 °С by scanning probe cryonanotomography technique with use of experimental setup combining cryoultramicrotome and scanning probe microscope.Results. Three-dimensional nanotomographical reconstructions of HepG2 cells adhered to macropore wall of regenerated silk macrocarrier and to spherical alginate microcarrier are obtained. Morphological parameters (mean roughness, effective surface area and autocorrelation length) are determined for surfaces of macro and microcarriers and adhered cells. The determined mean roughness of alginate microcarrier surface is 76.4 ± 7.5 nm, while that of surface of macropore wall of regenerated silk macrocarrier is 133.8 ± 16.2 nm. At the same time mean roughness of cells adhered to micro- and macrocarriers are 118.5 ± 9.0 и 158.8 ± 21.6 nm correspondingly. Three-dimensional reconstructions of intracellular compartments with dimensions from 140 to 500 nm are also obtained.Conclusion. Obtained as a result of study quantitative morphology characteristics of surfaces of cell carriers and adhered cells show signifi cant degree of correlation of morphological parameters of cells and their carriers. Use of scanning probe cryonanotomography technique for three-dimensional analysis of structure and characteristics of biomaterials, cells and bio-artifi cial cellular systems enables to improve effi ciency of development of novel cell-engineered constructions with predicted morphological, physical, chemical and biological characteristics for tasks of tissue engineering and regenerative medicine.

Investigation of soil water infiltration at a scale of individual earthworm channels

This study focused on the hydraulic efficiency of vertical earthworm channels (henceforth referred to as macropores or channels). The parameters selected for investigation were the rate of change in hydraulic soil conductivity in the channel walls due to compaction, the rate of this compaction, and the wall stability against running and stagnant water. We preferentially tested the variants for infiltration of water flowing from the soil horizons against gravity (e.g. from the level of installation of tile and controlled drainage). The details of influx and infiltration processes were examined both in the field and more thoroughly in the laboratory using an accurate continuous infiltrometer constructed at the Research Institute for Soil and Water Conservation (RISWC), Czech Republic. Both direct measurements and indirect evidence consisted of tests of individual natural macropores directly in the field, as well as tests of intact collected samples and artificial samples with variants of natural, artificially extruded, and cut out tubular macropores. We studied the processes occurring in macropores with diameters of ca. 5 mm and larger. In these particular conditions, we identified the apparent saturated hydraulic conductivity (K<sub>s</sub>') of the soil horizons (including macropore-mediated vertical surface infiltration and preferential flow to soil followed by radial infiltration) most frequent as K<sub>i</sub> (apparent saturated hydraulic conductivity affected by preferential flow or influx of water) from 50 to 200 cm/h. In some cases, saturated hydraulic conductivity of earthworm channel walls (K<sub>sw</sub>) was reduced in the order of tens of percent compared with matrix K<sub>s</sub>. The increase of bulk density of soil (ρ<sub>d</sub>) in the macropore vicinity reached the maximum of 25%. The intensity of macropore wall erosion (i<sub>er</sub>) ranged from 0 to 70 mg/min/dm<sup>2</sup>.

Three-dimensionally ordered hierarchically porous polypyrrole loading sulfur as high-performance cathode for lithium/sulfur batteries

A novel three-dimensionally (3D) ordered hierarchically porous polypyrrole (3DOHPPy) is successfully synthesized via a simple chemical polymerization method by using silica colloidal crystals as templates. The 3DOHPPy possesses a large BET specific surface area (118.5 m2 g−1), 3D ordered interconnected macropores (240 nm) and mesopores (2–3 nm) on the macropore walls. The sulfur/3DOHPPy (S/3DOHPPy) composite is prepared by a solution-diffusion route followed by low-temperature heat treatment and studied as a cathode material for the lithium/sulfur (Li/S) battery. The resulting S/3DOHPPy cathode shows a high specific discharge capacity of 751 mAh g−1 even after 100 cycles at 0.1 C and great rate capability. The superior electrochemical property of the S/3DOHPPy composite is ascribed to the unique hierarchical structure of 3DOHPPy with ordered interconnected macropores that benefit enhanced mass transfer and the small mesopores on the macropore walls that can immobilize the sulfur and polysulfides produced during the discharge/charge processes.

Two-dimensional distribution of soil organic carbon at intact macropore surfaces in BT-horizons

In structured soils, the surfaces of biopores, shrinkage cracks, and inter-aggregate spaces are often enriched in organic matter (OM) as compared to the matrix. The small-scale distribution of OM at macropore surfaces is affecting preferential flow, mass transfer, and OM turnover in macropores. While the mm-scale spatial distribution of the OM composition at intact surfaces could be observed, the distribution of the organic carbon (OC) content remained limited to date due to a suitable approach. The objective was to develop and test a method for quantifying the two-dimensional (2D) OC distribution at intact macropore surfaces at the mm-to-cm scale. We combined diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy and OC analyses of reference samples of few milligrams manually separated from macropore surfaces. DRIFT spectra were measured in a mapping approach at intact surfaces from earthworm burrows, cracks with and without clay-organic coatings, and single pore fillings (‘pinholes’) from Bt-horizons of Luvisols developed on loess and glacial till. The sample’s OC contents were determined with elemental isotope ratio mass spectrometry (EA-IRMS) and related to the DRIFT spectra by partial least squares regression (PLSR). The DRIFT mapping spectra were used to predict the 2D spatial distribution of the OC content at intact macropore surfaces via the PLSR models. The maps revealed mm-scale differences in the OC contents of the macropores which were often related to the 2D distribution of the macropore type surfaces. The validation of the PLSR showed R2 values of 0.77 (loess) and 0.83 (till) between measured and predicted OC contents. The prediction accuracy of the OC values was reduced by the micro-topography of the intact surfaces and by a variable thickness of the clay-organic surface layer. DRIFT mapping spectra from intact soil macropore surfaces were suitable to quantify the 2D OC distribution of the outermost surface layer. The heterogeneous small-scale spatial distribution of the OC contents at macropore surfaces implies a more specific consideration of these macropore walls when studying inter-domain mass transfer and OM turnover in structured soils.

Programmable Macroporous Photonic Crystals Enabled by Swelling‐Induced All‐Room‐Temperature Shape Memory Effects

AbstractThis study reports unconventional, all‐room‐temperature shape memory (SM) effects using templated macroporous shape memory polymer (SMP) photonic crystals comprising a glassy copolymer with high‐glass transition temperature. “Cold” programming of permanent periodic structures into temporary disordered configurations can be achieved by slowly evaporating various swelling solvents (e.g., ethanol) imbibed in the interconnecting macropores. The deformed macropores can be instantaneously recovered to the permanent geometry by exposing it to vapors and liquids of swelling solvents. By contrast, nonswelling solvents (e.g., hexane) cannot trigger “cold” programming and SM recovery. Extensive experimental and theoretical investigations reveal that the dynamics of swelling‐induced plasticizing effects caused by fast diffusion of solvent molecules into the walls of macropores with nanoscopic thickness dominate both “cold” programming and recovery processes. Importantly, the striking color changes associated with the reversible SM transitions enable novel chromogenic sensors for selectively detecting trace amounts of swelling analytes mixed in nonswelling solvents. Using ethanol–hexane solutions as proof‐of‐concept mixtures, the ethanol detection limit of 150 ppm has been demonstrated. Besides reusable sensors, which can find important applications in environmental monitoring and petroleum process/product control, the programmable SMP photonic crystals possessing high mechanical strengths and all‐room‐temperature processability can provide vast opportunities in developing reconfigurable/rewritable nanooptical devices.

Three-dimensionally ordered macroporous CeO2/Al2O3-supported Au nanoparticle catalysts: Effects of CeO2 nanolayers on catalytic activity in soot oxidation

A series of catalysts consisting of three-dimensionally ordered macroporous (3DOM) x-CeO2/Al2O3-supported Au nanoparticles (x = 2, 10, 20, and 40 wt%) were successfully synthesized using a reduction-deposition method. These catalysts were characterized using scanning electron microscopy, the Brunauer-Emmett-Teller method, X-ray diffraction, transmission electron microscopy, ultraviolet-visible spectroscopy, and temperature-programmed reduction by H2. Au nanoparticles of mean particle size 5 nm were well dispersed and supported on the inner walls of uniform macropores. The 3DOM structure improved the contact efficiency between soot and the catalyst. An Al-Ce-O solid solution was formed in the multilayer support, i.e., x-CeO2/Al2O3, by the incorporation of Al3+ ions into the CeO2 lattice, which resulted in the creation of extrinsic oxygen vacancies. Strong interactions between the metal (Au) and the support (Ce) increased the amount of active oxygen species, and this promoted soot oxidation. The catalytic performance in soot combustion was evaluated using a temperature-programmed oxidation technique. The presence of CeO2 nanolayers in the 3DOM Au/x-CeO2/Al2O3 catalysts clearly improved the catalytic activities in soot oxidation. Among the prepared catalysts, 3DOM Au/20%CeO2/Al2O3 showed high catalytic activity and stability in diesel soot oxidation.