SiO2 Spheres Research Articles

Ecofriendly magnetic nanocomposite (Fe3O4/SiO2/Ag) fabrication for sustainable dye wastewater management: catalysis and SERS for a cleaner approach.

Our study focuses on sustainable dye wastewater management through catalysis, scrutinized by surface-enhanced Raman spectroscopy (SERS) using an ecofriendly magnetic nanocomposite (Fe3O4/SiO2/Ag (FSA)). To our knowledge, the use of green synthesis for fabricating nanocomposites from a single source, namely Nerium oleander leaves, has not been extensively explored. This poses a distinctive and challenging approach, differentiating it from conventional chemical methods. Analytical investigations confirm the nanocomposite morphology, featuring Fe3O4 cubic cores with SiO2 spheres and silver nanoparticles (AgNPs) decoration. Efficient catalysis rapidly degrades unary and binary dye systems (MB, RhB, and MB + RhB), with high efficiency in short durations (MB: 96% in 10min, RhB: 94% in 2min, MB + RhB: 96% MB and 91% RhB in 9min) and with elevated "k" values. SERS monitors water quality, revealing complete degradation and quenching of dye fingerprints with fabricated nanocomposite FSA. The nanocomposite exhibits reusability over four cycles by easy recovery of catalyst with external magnet. The nanocomposite achieved 89.7% degradation efficiency in real-time household wastewater treatment. The proposed research aligns with UN SDGs 6 and 15 and this approach holds promise for advancing industrial waste management.

Gel polymer electrolytes containing SiO2 spheres with tuned sizes to increase rechargeability of quasi-solid-state Zn-air batteries

Rechargeable zinc–air batteries (RZABs) with high energy densities and low costs have attracted tremendous interest for meeting the ever-growing demand for flexible and portable applications. In these batteries, the quasi-solid/solid-state electrolyte plays a critical role in the battery performance, such as the cycling performance rate and power output. In this study, porous poly (vinyl alcohol) (PVA) and poly (acrylic acid) (PAA) composite gel polymer electrolytes (GPEs) were modified by incorporating SiO2 as a water retainer. For this reason, SiO2 spheres of different sizes were synthesized by varying the temperature (5, 20, 60, and 80 °C) and reaction time (2, 6, 18, and 24 h). According to the SEM micrographs, the average size ranged from 107 to 710 nm depending on the conditions. The porous PVA/PAA–SiO2 GPEs obtained by selecting three SiO2 sizes (107, 425, and 630 nm) exhibited higher water retention capability than the unmodified GPE. Among them, the GPE with SiO2–630 nm displayed the highest battery performance (1.46 V, 85 mWcm−2 @ 0.8 V). This was achieved using CoMn2O4 spinel as a bifunctional electrocatalyst, with a catalyst loading of 2 mg cm−2. The quasi-solid-state RZAB displayed twice the rechargeability of the RZAB assembled with Pt/C+IrO2/C (120 vs. 62 cycles). According to post-mortem tests, this can be related to the improved water retention, the decrease in the size of the formed Zn dendrites, and the stability of the bifunctional material. Thus, fine-tuning of the electrocatalyst/electrolyte interface strongly affects the rechargeability.

Transparent composite-structure antifogging coating with mechanical abrasion resistance and environmental durability

Superhydrophilic SiO2 coatings offer unparalleled advantages in terms of antifogging properties. However, they show suboptimal mechanical abrasion resistance and environmental durability, limiting their application. Accordingly, research has focused on the trade-off between hydrophilicity and mechanical abrasion resistance as well as between environmental durability and visible transmittance in superhydrophilic SiO2 coatings. Herein, a composite-structure coating with a densely distributed particulate phase and enhanced crosslinking strength is developed without the use of organic compounds. The coating exhibits remarkable transparency and antifogging properties, with an average transmittance similar to that of bare glass and a water contact angle of approximately 0°. Moreover, the coating exhibits impressive hardness and adhesion of up to 4H and 5B, respectively. The coating retained its antifogging properties even after undergoing 500 cycles of wear induced using a 3000-mesh sandpaper, impact of sand (40 g) dropped from a height of 40 cm, 10 weeks of exposure to the outdoor environment, and 25 h of immersion in water. The test results demonstrate that the coating exhibits satisfactory mechanical abrasion resistance and environmental durability, which are essential for its practical applications. The composite structure formed using linear SiO2 molecules as crosslinking agents with spherical SiO2 nanoparticles considerably enhances the adhesion and abrasion resistance of the coatings. Overall, the developed composite-structure coatings will facilitate their commercial viability and expand the application of superhydrophilic materials in various research fields.

Effect of precursor morphology on the electrochemical performance of porous Si anodes prepared by magnesiothermic reduction

The magnesiothermic reduction of SiO2 to Si is a promising route for preparing high-energy-density Si-based anode materials for lithium-ion batteries. However, the effect of the initial morphological properties of SiO2 on the electrochemical performance of Si remains unclear. Herein, porous Si (PSi) particles were prepared from four different SiO2 precursors, namely, spherical SiO2 particles with diameters of 0.3 and 20 μm (denoted SiO2-0.3 and SiO2-20, respectively), fumed SiO2 powder (denoted SiO2-F), and well-ordered mesoporous SiO2 particles (denoted SiO2-K). Highly crystalline PSi particles were obtained after magnesiothermic reduction and subsequent HCl and HF etching. PSi prepared from SiO2-0.3 maintained its precursor morphology to some extent, whereas highly irregular Si particles were produced from SiO2-20, SiO2-F, and SiO2-K. Among the PSi particles, those prepared from SiO2-0.3 delivered the highest reversible capacity (1427 mAh g–1 at 0.1 A g–1) after 50 discharge–charge cycles. Because of the unique hierarchically porous morphology of PSi prepared from SiO2-0.3, the expansion of its electrode thickness was suppressed below 140 %. Moreover, owing to its nanosized Si domains and good electrode wetting, PSi prepared from SiO2-0.3 demonstrated improved electrochemical properties compared with those prepared from SiO2-F and SiO2-K.

A Time-Interval Strategy to Prepare Porous SiO2 Spheres with Adjustable Core-Shell Ratio for Multiple Guest Loading.

Porous microspheres with desired pore size and distribution are in high demand for loading various guest materials, especially various pollutants that are several nanometers in size or stably suspended in liquid. Herein, multilevel porous SiO2 microspheres with arbitrarily adjustable core-shell ratios are prepared by solely regulating the time interval between the start of the hydrolysis reaction and the addition of organic solvent. The core-shell ratio of the SiO2 microspheres increases gradually with prolongation of the addition time interval; meanwhile, the specific surface area can be adjusted from 543.2 m2 g-1 to 992.9 m2 g-1, and the average pore diameter varies from 2.3 to 5.7 nm together with a high pore volume reaching 0.91 cm3 g-1. Moreover, the hierarchical core-shell SiO2 microspheres with an adjustable core-shell ratio, a large specific surface area, and a multilevel pore size could be obtained on a large scale. These SiO2 microspheres demonstrate excellent performance in coloading platinum nanoparticles and various dye molecules, suggesting their great potential in treating various pollutants in printing and dyeing wastewater.

Highly sensitive toluene sensor based on silver Ear-Like F-doped Co3O4 templated from Co(OH)F Guided by SiO2 nanospheres

This study successfully synthesized “silver ear-like” Co(OH)F using 15 nm SiO2 spheres as seeds. Gas sensitivity of Co(OH)F with and without SiO2 spheres to toluene was compared at different annealing temperatures. The results demonstrate that the Co(OH)F-Si-350 sensor exhibits optimal gas sensitivity to toluene, with a response of 35 (Rg/Ra) to 100 ppm of toluene at 220℃, with response and recovery times of 50 s and 80 s, respectively. Notably, the sensor detected toluene concentrations as low as 50 ppb, indicating good sensitivity to low concentrations. These findings suggest that the structural transformation resulting from the introduction of SiO2 nanospheres, forming ultra-thin nanosheet clusters (∼12 nm), provides abundant active sites, effectively promoting substance diffusion and adsorption/desorption processes. Additionally, the incorporation of fluorine enhances the Lewis acidity of the material, facilitating the formation of stable adsorption states for gas molecules on the surface. These results reveal the significant impact of the structural transformation caused by the introduction of SiO2 nanospheres on gas sensitivity, providing a strong theoretical foundation for further optimizing gas sensor design.

Detection of topology freezing transition temperature of vitrimers based on photonic coatings from photonic crystals and vitrimers

There are a few methods to measure topology freezing transition temperature (Tv) of vitrimers while the samples are needed to be under external force or additional substances. The novel photonic coatings from the lower photonic crystals (PCs) and the upper vitrimers are fabricated and used to detect Tv of vitrimers. The photonic coatings have photonic stopbands (or structural colors) because of PCs. When photonic coatings are heated, PCs from SiO2 spheres are stable, vitrimers are transformed from solid state to fluid state, light would be easily pierced through vitrimers and reflect off PCs, the intensities of reflection peaks of photonic coatings increase slowly, increase sharply and keep unchanged at three stages. So Tv of vitrimers are directly observed and obtained according to these great changes. The values of Tv of the vitrimers from different synthesis conditions are different. The novel method is simple, intuitive and without external force and additional substances. The photonic coatings also have good toluene-resistance and self-healing property. They have potential applications in detection of Tv of other vitrimers, displays, anti-counterfeiting and automotive coatings.

Increasing Light-Induced Forces with Magnetic Photonic Glasses

In this work, we theoretically and experimentally study the induction of electromagnetic forces in an opal-based magnetic photonic glass, where light normally impinges onto a disordered arrangement of SiO2 spheres by the aggregation of Fe3O4 nanoparticles. The working wavelength is 633 nm. Experimental evidence is presented for the force that results from forced oscillations of the photonic structure. Finite-element method simulations and a theoretical model estimate the magnetic force volumetric density value, peak displacement, and velocity of oscillations. The magnetic force is of the order of 56 microN, which is approximately 500-times higher than forces induced in dielectric optomechanical photonic crystal cavities.

Ablation behavior and mechanisms of Cf/(CrZrHfNbTa)C‒SiC high‐entropy composite at temperatures up to 2450°C

AbstractThe oxide layer formed by ultra‐high melt point oxides (ZrO2, HfO2) and SiO2 glassy melt is the key to the application of traditional thermal structural materials in extremely high‐temperature environment. However, the negative effect of ZrO2 and HfO2 phase transitions on the stability of oxide layer and rapid volatilization of low viscosity SiO2 melt limit its application in aerospace. In this study, the ablation behavior of Cf/(CrZrHfNbTa)C‒SiC high‐entropy composite was explored systematically via an air plasma ablation test, under a heat flux of 5 MW/m2 at temperatures up to 2450°C. The composite presents an outstanding ablation resistance, with linear and mass ablation rates of 0.9 µm/s and 1.82 mg/s, respectively. This impressive ablation resistance is attributed to the highly stable oxide protective layer formed in situ on the ablation surface, which comprises a solid skeleton of (Zr, Hf)6(Nb, Ta)2O17 combined with spherical particles and SiO2 glassy melt. The irregular particles provide a solid skeleton in the oxides protective layer, which increased stability of the oxide layer. Moreover, the spherical particles have a crystal structure similar to that of Ta2O5 and are uniformly distributed in SiO2 glassy melt, which hinder the flow of SiO2 glassy melt and enhance its viscosity to a certain degree. And it reduces the volatilization of SiO2. In summary, the stable oxide layer was formed by irregular particles oxide and the SiO2 glassy melt with certain viscosity, thereby resulting in the impressive ablation resistance of the composite. This study fills a gap in ablation research on the (CrZrHfNbTa)C system.

Controllable synthesis of NiCoMo-LDH with nanofloral structure assisted by monodisperse spherical silica for asymmetric supercapacitor

Traditional layered double hydroxides (LDH) have disadvantages such as small layer spacing, insufficient active sites and poor electrical conductivity, which seriously restricts their future utilization in the realm of energy storage. In this paper, a controlled synthesis strategy of tercomponent metal NiCoMo-LDH is proposed by using the structural advantages of metal-organic skeleton (MOF) templates, combining structural regulation and atom doping. On the basis of the synthesis of Ni-MOF 74, Co and Mo atoms are introduced for a small amount of doping, and the monodisperse spherical SiO2 is inserted to adjust the pore structure of NiCoMo-MOF, expand the lamellar spacing, and effectively avoid the accumulation and agglomeration of lamella. Finally, NiCoMo-LDH cathode material with loose porous and coarsely curled nanosphere structure was synthesized through the chemical reaction of OH− with SiO2 and the destruction of the skeleton structure of MOF. The specific capacitance of the material is 1423.3 F·g−1 at 0.5 A·g−1, and after 5000 cycles of charging and discharging, 80.0% of the original specific capacitance is sustained. Moreover, NiCoMo-LDH//AC ASC possesses a high energy density of 39.1 Wh·kg−1 at the power density 400 W·kg−1. Combined with density functional theory (DFT) calculation, the fact that metal doping can not only effectively improve the conductivity of electrode materials has been further proved, but also accelerate the electron/ion migration rate, which successfully reveal the synergistic enhancement mechanism of electrochemical properties of materials.

Switchable optical trapping and manipulation enabled by polarization-modulated multifunctional phase-change metasurfaces

Optical trapping, a cutting-edge methodology, is pivotal for contactlessly controlling and exploring microscopic objects. However, it encounters formidable challenges such as multiparticle trapping, flexible control, and seamless integration. Here, we employ a polarization-modulated multi-foci technique for versatile nanoparticle trapping using multifunctional metasurfaces relying on geometric phase. Numerical simulations demonstrate the generation of two focused spots with orthogonal polarization distributions through our metasurfaces when illuminated with linearly polarized light, with their polarization distributions be interchanged by orthogonally switching the incident polarizations. We extend this design to an array of multi-foci metasurface tweezers modulated by polarization, highlighting the versatility and robustness of our approach. Furthermore, we demonstrate the simultaneous generation of two distinct focusing cylindrical vector beams using a monolayer metasurface, showcasing the two vector beams possess the interchange ability of their polarization distributions. By leveraging the Maxwell stress tensor, we assess the distinct contributions of the focused beams to longitudinal and transverse optical forces on SiO2 spheres, validating diverse trapping and manipulation behaviors for nanoparticles with the proposed metasurface designs. By manipulating the phase states of Sb2S3 nanopillars, binary-switchable optical trapping and manipulation are facilitated for all proposed metasurface tweezers. Our work underscores the efficacy of polarization-modulation multifunctional metasurface tweezers in consolidating multiple trapping tasks into a single device, paving the way for innovative lab-on-a-chip optical trapping applications in biophysics, nanotechnology, and photonics.

Enhancing thermal consistency and stability of quantum dots through encapsulation: A study on microscale-structured hybrid for WLEDs

Quantum dots (QDs) are regarded as highly potential materials for color conversion in light-emitting diodes (LEDs) and display technologies owing to their distinctive and outstanding optical characteristics. Nevertheless, the energy transfer process occurring among various colored QDs, known as Förster resonance energy transfer (FRET), results in a notable redshift in fluorescence emission, restricting the precise control of photoluminescence spectra in fabricated devices. This study presents a dual-impact technique to enhance the stability of CdSe/ZnS colloidal QDs while also preventing the FRET process. This is achieved by encapsulating the QDs within silica (SiO2) and ethylene-vinyl acetate (EVA) films. The research features two distinct encapsulation methods: enveloping multiple QDs within a SiO2 matrix (MQD) and adsorbing QDs onto SiO2 spheres as a shell (SQD and SQDS). Those hybrid structures are successfully fabricated with their nanostructure, chemical composition, and optical properties extensively analyzed. Moreover, the photo-physical properties of QDs/SiO2/EVA hybrid composite films and their impact on blue lightemitting diodes (LEDs) and White-LEDs have been conducted. Among those formulations explored, the MQD/EVA films stand out, displaying natural sunlight color emission with a color temperature of 4214 K, a color coordinate at (0.37, 0.37), and significant improvements in chromatic and thermal stability under high driving power. The successful integration of high-molecular-weight polymers and SiO2 coatings highlights the effectiveness of this approach in producing robust, high-quality QD-polymer film composites, making them ideal candidates for display technologies.

Study of damage mechanism on single crystal 4H-SiC surface layer by picosecond laser modification (PLM)

The stable structure, high hardness, and brittleness of single-crystal 4H-SiC present challenges in achieving efficient and damage-free polishing processing. Ultra-short pulsed laser-induced surface modification provides a new solution to enhance the manufacturability of 4H-SiC. This paper aims to investigate the underlying mechanism of the picosecond laser-induced surface structural changes in 4H-SiC and the process of material removal from solid to vapour, elucidating the interaction mechanism between picosecond laser and 4H-SiC. A temperature gradient distribution model for picosecond laser irradiation on 4H-SiC was built to reveal the formation mechanism of subsurface crack damage. The results show that a combination of phase explosion and thermal effects controlled picosecond laser-modified 4H-SiC surfaces deposited spherical SiO2 particles and the process. The study demonstrates that the cracking behaviour in the subsurface of picosecond laser-modified SiC predominantly occurs in the recast region. The fundamental cause of cracking is attributed to the tensile stresses generated by thermal effects and the volumetric changes in the molten material resulting from the overlapping of neighbouring spots in alternating hot–cold cycles. The nanoindentation demonstrated that laser modification can effectively enhance the machinability of SiC. The findings of this study can provide a theoretical basis for efficient non-destructive machining of hard and brittle materials.

Comparing novel small-angle x-ray scattering approaches for absolute size and number concentration measurements of spherical SiO2 particles to established methods

Biomedical analytical applications, as well as the industrial production of high-quality nano- and sub-micrometre particles, require accurate methods to quantify the absolute number concentration of particles. In this context, small-angle x-ray scattering (SAXS) is a powerful tool to determine the particle size and concentration traceable to the Système international d’unités (SI). Therefore, absolute measurements of the scattering cross-section must be performed, which require precise knowledge of all experimental parameters, such as the electron density of solvent and particles, whereas the latter is often unknown. Within the present study, novel SAXS-based approaches to determine the size distribution, density and number concentrations of sub-micron spherical silica particles with narrow size distributions and mean diameters between 160 nm and 430 nm are presented. For the first-time traceable density and number concentration measurements of silica particles are presented and current challenges in SAXS measurements such as beam-smearing, poorly known electron densities and moderately polydisperse samples are addressed. In addition, and for comparison purpose, atomic force microscopy has been used for traceable measurements of the size distribution and single particle inductively coupled plasma mass spectrometry with the dynamic mass flow approach for the accurate quantification of the number concentrations of silica particles. The possibilities and limitations of the current approaches are critically discussed in this study.

ZnO Doped Silica Nanoparticles (ZnO@SiO2) for Enhanced Electrochemical Detection of Cd2+ Ions in Real Samples.

Pollution by heavy metal ions has a serious impact on human health and the environment, which is why the monitoring of heavy metal ions is of great practical importance. In this work, we describe the development of an electrochemical sensor for the detection of cadmium (Cd2+) involving the doping of porous SiO2 spheres with ZnO nanoparticles. Zinc oxide is chosen as the central dopant in the composite material to increase the conductivity and thus improve the electrochemical detection of Cd2+ ions with the SiO2 spheres. The resulting composite is characterized by electrochemical spectroscopic XRD and microscopic methods. As a result, the developed sensor shows good selectivity towards the targeted Cd2+ ions compared to other divalent ions. After optimization of the experimental conditions, the electrochemical sensor shows two different linear ranges between 2.5 × 10-11 molL-1 to 1.75 × 10-10 molL-1 and 2 × 10-9 molL-1 to 1.75 × 10-9 molL-1, indicating a change from diffusion-controlled to surface-controlled oxidation of Cd2+. A detection limit was reached at 4.4 × 10-11 molL-1. In addition, it offers good repeatability and recovery, and can detect accurate trace amounts of Cd2+ ions in real samples such as tap water or seawater by spiking these samples with known Cd2+ concentrations. This setup also provides satisfactory recovery rates in the range of 89-102%.

Optimization of the process synthesis of silica nanoparticles functionalized with silane agents destined for superhydrophobic coating

The aim of this study is to define the optimum process synthesis of silica (SiO2) nanoparticles functionalized with silane agents destined for superhydrophobic coating thus to determine the minimum required silane agent needed to obtain proper superhydrophobic properties. Spherical SiO2 nanoparticles were synthesized by using sol-gel method and functionalized to gain hydrophobic properties with two different silane agents: 1,1,1,3,3,3-hexamethyldisilazane (HMDS) and 1H,1H,2H,2H – perfluoroctyltrichlorosilane (PFOTS). The hydrophobic properties were evaluated by measuring the water drop contact angle and the inclination flowing angle. Results show that, through manufacturing process optimization, the quantity of HMDS could be reduced by 142%, while the quantity of PFOTS could be reduced by 20% compared to the lab scale synthesis method developed by ICPE-CA, without having a negative effect on the hydrophobic properties of the functionalized SiO2 nanoparticles.

Ablation behavior of microwave absorbing SiCf/Si3N4 composites containing ZrOC–SiCN matrix

The thermal protection materials of ultra-high speed aircraft need the stealth performance, and it require the microwave absorbing materials should have high ablation resistance to serve under extreme conditions (>2000 °C). In this work, amorphous ZrOC–SiCN and SiCN were introduced into the inter-bundle matrix of SiC fiber reinforced Si3N4 matrix composites to improve the ablation resistance while retaining the wave-absorbing properties. For SiCf/Si3N4, the SiC nanocrystallines in SiC fiber are oxidized into SiO2 and accumulate on the surface, and the Si3N4 matrix is first transformed into SiC grains and then the SiC grains are gradually ablated into spherical SiO2 in the ablation process. After the introduction of ZrOC–SiCN and heat-treated at 1500 °C, the ZrCN can be formed to increase the scouring resistance of each woven layer, and the oxide film with high viscosity also can be formed, preventing the fiber bundles from being blown away in the central region, leading to the decrease of mass and line ablation rate from 12.2 mg/s and 27.3 μm/s to 7.3 mg/s and 16 μm/s, respectively. Meanwhile, the minimum reflection coefficient of the composite decreases from −4.9 to −10.6 dB.

Ru nanoparticles embedded in Ru/SiO2@N-CS for boosting hydrogen production via ammonia decomposition with robust lifespan

Ammonia decomposition for onsite hydrogen production has been regarded as an important reaction which links to efficient hydrogen storage, transport and utilization. However, it still remains challenging to develop efficient catalysts with robust stability for ammonia decomposition. Herein, an integrated strategy was employed to synthesize Ru/SiO2@N-CS via wrapping a thin layer of N-doped carbon onto the SiO2 sphere, following the anchor of Ru nanoparticles (NPs) onto the support. The obtained Ru/SiO2@N-CS (Ru loading: 1 wt%) shows a promising performance for ammonia decomposition, reaching 94.5 % at 550 °C with a gas hourly space velocity (GHSV) of 30 000 mL gcat-1h−1. The combination of the SiO2 as the core prevents the degradation of N-doped carbon layers and then enhance the durability of the catalysts, remaining stable after 50 h at evaluated temperatures. Adequate characterizations were used to illustrate the effect of microchemical environment on ammonia decomposition activity of Ru/SiO2@N-CS catalyst under different calcination atmosphere and the correlation between structure and performance.

Cobalt/nitrogen doped hollow carbon sphere-bamboo like carbon nanotube for highly efficient oxygen reduction reaction

The exploration of non-Pt catalysts with high electrocatalytic activity and durability is especially important for cathodic oxygen reduction reaction (ORR) in fuel cell. Here, cobalt and nitrogen doped hollow carbon sphere-bamboo like carbon nanotube (Co/NHCS-BCNT) is prepared by using SiO2 sphere as sacrificial template. Co nanoparticles are confined in the cavity and top end of the in-situ formed BCNT, which can not only avoid the agglomeration of Co nanoparticles but also inhibit corrosion in caustic electrolyte. The synergistic effect between NHCS and well-dispersed Co particles makes Co/NHCS-BCNT have superior catalytic activity toward ORR. The electrochemical surface area (ECSA) of Co/NHCS-BCNT is 222 cm2, which is higher than those of NHCS (164 cm2) and HCS (135 cm2). The onset potential and half-wave potential of Co/NHCS-BCNT are 0.941 V and 0.814 V, respectively, which are close to commercial Pt/C (0.949 V, 0.807 V). The Tafel slope of Co/NHCS-BCNT (63.8 mV dec-1) is lower than that of Pt/C (71.7 mV dec-1). In addition, Co/NHCS-BCNT shows excellent durability and fuel selectivity.

Doped Porous Carbon Spheres with Controllable Vesicle Structure: Preparation and the Effects of Pore Size on Electromagnetic Wave Absorption Properties.

This work reports on the preparation of uniform vesicle-structural carbon spheres doped with heteroatoms of N, P, and S, with the pore sizes strictly controlled by the hard templates of monodisperse submicron SiO2 spheres. The uniformly doped vesicular carbon microspheres are obtained in three steps: Stöber hydrolysis for the SiO2; in situ polymerization for the immobilization; and alkaline etching after carbonization. The size of the vesicles can be easily adjusted by regulating the particle size of the submicron SiO2 spheres, which has a significant effect on its electromagnetic wave (EMW) absorption performance. Compared with microspheres with pore sizes of 180 and 480nm, when the vesicle aperture is 327nm, with only 5.5wt.% filling load and 1.9mm thickness, the material shows the best EMW absorption behavior with the effective absorption bandwidth (EAB) covers the entire Ku band (6.32GHz) and the minimum reflection loss (RLmin) of -36.10dB, suggesting the optimized pore size of the microspheres can significantly improve the overall impedance matching of the material and achieve broadband wave absorption. This work paves the way for the enhancement of EMW absorption properties of porous material by optimizing the pore size of uniform apertures while maintaining their composition.