Porous Hollow Research Articles

Vibration analysis of a porous hollow conical rotor with circumferentially distributed piezoceramic strips

The present study investigates vibrational behavior of a porous conical hollow rotor. Inner and outer rotor surface, sensor, and actuator strips made of piezoceramic are modeled and positioned, which are symmetrically distributed in the circumferential direction. Kinetic and potential energies were computed considering the effects of Coriolis and centrifugal force. Modeling of the system has been carried out assuming classical theory and using Lagrange approach for simple-supported boundary conditions. Also, the relations of piezoceramic and three types of porosity attend in equilibrium equations. The discretization of kinetic and potential energies using displacement field which is defined as double mixed series based on independent mode shape and time function leads to obtaining the equations in form of ordinary differential. To calculate the natural frequencies, the equations were converted to a special form of state space model. The correctness of the study is examined by comparing it with similar study results. The most consequential parameters affecting the forward and backward natural frequency, such as type and porosity coefficient, size, number, and thickness of piezoceramic, and the rotor angular velocity, are researched. The results demonstrate that the effect of porosity coefficient in various longitudinal modes on natural frequency is different.

Large gap cobalt‑vanadium oxide structure encapsulated in porous carbon for high performance capacitive deionization

The application of traditional electrode materials for high-performance capacitive deionization (CDI) has been persistently limited by their low charge-storage capacities and slow salt removal rates. In order to improve the electrochemical performance, cobalt‑vanadium coated porous carbon gradient hollow spheres (Co3V2O8@C) with large internal spacing, and high pore structure was prepared in this paper to improve the ion mobility. The structure with the following characteristics: (1) Co3V2O8@C with a reversible ionic insertion/de-insertion and good electrical conductivity; (2) the increased lattice spacing effectively mitigates volume expansion during prolonged cycling; (3) it increases the utilization rate of the active center inside the electrode material and shows high electrochemical adsorption capacity by being applied to capacitive deionization. When applied to CDI, Co3V2O8@C has top CDI performance compared to the currently reported cobalt-based electrode materials. The holding capacities for different ions (Cl−, SO42−, NO3−, and Na+) were 160, 161, 244, and 69 mg·g−1 with good cycling stability after 100 h. Our research provides a reasonable pathway for building the structure of high-capacity cobalt-based electrodes and further promoting the development of high-performance CDI electrode materials.

Cobalt-Based Active Sites Embedded in Hollow Porous Carbon Nanocages for the Hydrogenation of Nitroarenes

Cobalt-Based Active Sites Embedded in Hollow Porous Carbon Nanocages for the Hydrogenation of Nitroarenes

Phytic acid-assisted fabrication of porous leaf-like hollow structured Co2P @ C for efficient hydrogen evolution

Transition metal phosphides (TMPs) are considered promising electrocatalysts for the hydrogen evolution reaction (HER). Although wet-chemistry and gas-solid reaction methods are widely used for TMPs synthesis, it remains challenging to synthesize porous hollow structured TMPs via a facile, green and sustainable pathway. We report here an eco-friendly phytic acid (PA)-assisted phosphidation strategy to synthesize a novel porous leaf-like hollow structured Co2P @ C catalyst (Co2P @ C ML). Its synthesis involves precipitation of leaf-like microstructured Co-based zeolitic-imidazolate frameworks (Co-ZIF ML), chemical etching of Co-ZIF ML to form PA cross-linked Co complexes and a final pyrolysis step to get Co2P @ C ML with abundant Co2P nanoparticles loaded on P-doped carbon matrix. The Co2P @ C ML catalyst demonstrates excellent HER catalytic performances with low overpotentials at 10 mA cm−2, small Tafel slopes and high catalytic durability in 0.5 M H2SO4 and 1 M KOH. The presented PA-assisted phosphidation synthetic strategy can be readily extended to the design and synthesis of other well-defined hollow structured TMPs@C materials for various applications.

Electrochemical behaviors of porous spherical spinel H1.6Mn1.6O4 with high Li+ adsorption capacity

A self-assembled spherical H1.6Mn1.6O4 adsorbent with surface porous and internal hollow structure was successfully synthesized. Due to the special surface porous and internal hollow structure, the adsorbent exposes channels and interfaces for ions migration and ad/desorption, and also provides sites for charge transfer. At an initial Li+ concentration of 400 mg/L, the spherical adsorbent adsorption capacity of lithium can efficiently reach an extreme 47.54 mg/g in 360 min (the traditional adsorption route is 44.36 mg/g at 2880 min) without alkaline assistance by applying the electrochemical adsorption technique. In the multiple MCl (M = Li, Na, K, Rb, Cs) solution with each metal ion molar concentration of 14.41 mmol/L, the adsorbent adsorption capacity keeps 89.71% of a single LiCl solution. After the 5th cycle, the adsorption capacity to lithium remains at 94.98% (the traditional adsorption route is 86.65%) of the initial adsorption value. According to the analysis of cyclic voltammetry (CV) curves, it is found that the key kinetic factor limiting the adsorption rate is that the ions migration rate cannot catch up with the electrons transfer rate during the adsorption process. Furthermore, the electric field self-promotes the pH of the solution, and the corresponding alkaline environment is favorable for the adsorption behaviors. In the actual salt lakes brine, the 1st electrochemical adsorption capacity of the adsorbent for lithium is 3.26 mmol/g (Salt lake B), and the 5th adsorption capacity is 83.74% of the 1st adsorption value.

Zeolitic Imidazolate Frameworks Derived Co9 S8 /Nitrogen-Doped Hollow Porous Carbon Spheres as Efficient Bifunctional Electrocatalysts for Rechargeable Zinc-Air Batteries.

The development of nonprecious metal-based electrocatalysts with remarkable catalytic activity and long-cycling lifespan toward oxygen reduction reaction (ORR) and evolution reaction (OER) is especially important for rechargeable zinc-air batteries (ZABs). Herein, monodispersed Co9 S8 nanoparticles embedded in nitrogen-doped hierarchically porous hollow carbon spheres (Co9 S8 NPs/NHCS) are synthesized through a template-assisted strategy followed by a co-assembly, thermal annealing, and sulfurization process. Benefiting from larger specific surface area, hierarchically porous hollow structure, and carbon nanotubes self-growth, the obtained Co9 S8 NPs/NHCS-0.5 electrocatalyst exhibits decent performance for ORR (E1/2 =0.85 V) and OER (E10 =1.55 V). A rechargeable ZAB assembled using the Co9 S8 NPs/NHCS-0.5 as air cathode delivers a maximum power density of 116 mW cm-2 , high open circuit voltage of 1.47 V, and good durability (no obvious voltage decay after 1200 cycles (200 hours)). Such a hierarchically porous hollow structure of Co9 S8 NPs/NHCS-0.5 provides a confined space shell and an interconnected hollow core to achieve outstanding bifunctional catalytic activity and cycling stability, which surpass the benchmark Pt/C-RuO2 .

Preparation of Hollow Porous Carbon Nanofibers and Their Performance and Mechanism of Broadband Microwave Absorption.

Developing microwave absorbing composites with lightweight and wide absorption bands is an essential direction for electromagnetic wave stealth and shielding application. In this article, PAN/PMMA blend fibers and sheath-core blend fibers with PAN/PMMA as the sheath and PMMA as the core were spun by uniaxial and coaxial electrostatic spinning, respectively. Porous carbon nanofiber (PCNF) and hollow porous carbon nanofiber (HPCNF) were obtained after pre-oxidation and carbonization of the corresponding two precursor fibers. The microwave absorption composite samples with PCNF and HPCNF as absorbents and paraffin as matrix were prepared, respectively. Their electromagnetic parameters were investigated by the reflective-transmission network parameter method. The microwave absorption properties of the corresponding composites were calculated based on a model for a single-layer planewave absorber from electromagnetic parameters. The results showed diversity between the microwave absorbing performance of the composites filled with PCNF and HPCNF. HPCNF performs better than PCNF as an absorbent; that is, the lowest reflection loss of composite filled with HPCNF is −20.26 dB and the effective bandwidth (lower than −10 dB) is to 4.56 GHz, while the lowest reflection loss of a composite filled with PCNF is −13.70 dB, and the effective bandwidth (lower than −10 dB) is 2.68 GHz when the absorbent content is 7%, and the thickness is 3 mm. Much lower reflection loss and a wider absorption band could be expected from HPCNF. The presence of a hollow structure in HPCNF, which may increase the degree of polarization and provide more interfaces for the interference phase extinction of reflected electromagnetic waves, might help to improve the attenuation of electromagnetic waves and broaden the absorption band.

Scalable Preparation of Sub-Millimeter Double-Shelled Al2O3 Hollow Spheres and Their Rapid Separation from Wastewater after Adsorption of Congo Red.

Porous double-shelled ceramic hollow spheres (PDSs) have attracted extensive attention due to their high specific surface areas and multifunctional designs. When used in wastewater treatment, millimeter or sub-millimeter spheres can be quickly separated from water by commercial sieves. However, the simple, scalable, and low-cost preparation of sub-millimeter PDSs in the solid phase remains a challenge. Herein, porous PDSs were facilely fabricated via a spheronization process utilizing pseudoboehmite powders and wet gelatin spheres as templates, which broke through the difficulty of preparing PDSs by one-step solid-state synthesis. Treating pseudoboehmite powder with nitric acid can improve the compressive strength of the PDSs. By controlling the rolling time and gelatin concentration of gelatin microspheres, the integrity, shell thickness, and double-shelled spacing of the gelatin microspheres were tuned. When the rolling time was 8–12 min, and the gelatin concentration in gelatin spheres was 250 g/L, and PDSs with a complete double-shelled structure, good mechanical property, and high specific surface area (327.5–509.6 m2/g) were obtained at 600 °C. The adsorption capacities of the PDSs for 100 mg/L Congo red solution (70.7 mg/g) were larger than those of single-shelled hollow spheres (49 mg/g), and larger diameters (608–862 μm) of the PDSs allow them to be rapidly separated from solution by a commercial sieve. This paper provides a facile and scalable method for the preparation of sub-millimeter PDSs and demonstrates their excellent adsorption capacity for Congo red solution.

Template-Assisted Synthesis of Porous Manganese Dioxide Hollow Rods as Supercapacitor Electrode Material

Template-Assisted Synthesis of Porous Manganese Dioxide Hollow Rods as Supercapacitor Electrode Material

Porous Silicon Nano-Quill Anodes for Lithium-Ion Batteries

The growing population and increasing demands for energy are overwhelming our supply of fossil fuels and limiting the availability for future generations. Technologies for energy storage devices are emerging to replace conventional fuel-based technologies to meet emissions goals set by world governments and the rapid electrification of the transportation sector. Lithium-ion batteries (LIBs) are widely used for energy storage in devices across many commercial applications. LIB electrodes are continuously evolving due to demands for higher energy density and long cycling life. Among the recent developments in anode electrode materials, silicon (Si) is regarded as the most promising replacement for graphite due to its high theoretical specific capacity (~4200 mAh g-1), which is over 10 times greater than that of conventional graphite anodes (~372 mAh g-1). Despite the advancements, persisting challenges hinder the commercialization of Si for LIB anodes. Si-based electrodes are susceptible to rapid degradation due to the large volume change (approx. 400%) of Si particles during lithium insertion and extraction. The repeated volume change leads to the pulverization of the Si material, ultimately leading to decreased cycling stability from the loss of contact with the current collector. To overcome this obstacle, 3-dimensional porous and hollow nanostructures have been employed to provide sufficient void space to accommodate the volume change during electrochemical cycling. However, with the demands for material cost-reduction from industry, Si structures' strategic engineering must be cost-effective for commercial viability.Our team has developed a patent-pending cost-effective, scalable, and green methodology to use bio-renewable templates to synthesize a 3-dimensional Si architecture, called Si nano-quills (SiNQs). We innovated a two-step, cost-effective process that yields SiNQs with a porous morphology and hollow interior structure. First, in a scalable sol-gel process, silica gel particles were prepared using commonly available low-cost chemicals. The unique mesoporous SiNQ morphology was engineered using surfactant-modified cellulose nanocrystals as a bio-renewable sacrificial template. The templates were removed via thermal treatment to form silica nanoparticles. These particles, called silica nano-quills (SilicaNQs), possess a 3-dimensional bulk structure comprised of hollow quill-like arms and a high degree of porosity. In the second step, we employed a low-temperature magnesiothermic reduction method to convert SilicaNQs into SiNQs with a relatively large surface area. Anode electrodes were fabricated using SiNQs as the active material for electrochemical testing. The slurry was prepared using the active material, carbon black, and PVDF with a mass ratio of 60:20:20 coated onto an ion-permeable Bucky Paper (BP, a flexible and conductive paper made of carbon nanotubes). The 2032-type coin cells were assembled for battery testing using SiNQ electrodes (with an active mass loading of 1 mg cm-2) and a lithium metal chip as the counter electrode. The coin cells were cycled at a current rate of 0.1C (420 mA g-1) over the potential range of 0.01 – 1.0 V at room temperature. The SiNQ anode offered superior battery capacity retention of 73% of the initial reversible capacity of 963 mAh g-1 after 220 cycles. In comparison, batteries fabricated from the Mg reduction of commercially available mesoporous silica, SBA-15, offer capacity retention of only 52.6% after 100 cycles. The SiNQ precursor is engineered to possess porous walls with a superior BET surface area (1265 m2 g-1) compared to SBA-15 (550 m2 g-1). After Mg reduction, the SiNQs retain a BET surface area of 232 m2 g-1, whereas the surface area of reduced SBA-15 is 74 m2 g-1. The superior performance of SiNQs is due to their unique morphology that offers high surface area and porosity for effective diffusion of lithium ions and more sites for interactions with lithium ions, leading to a higher reversible capacity. Moreover, the porous architecture of SiNQs can effectively mitigate the volume change issue during lithiation and delithiation processes, thus providing a good cycling performance.

Snowball flower-like g-C3N4/ZnFe2O4 mesoporous hollow microspheres with enhanced triethylamine sensing properties

Herein, the snowball flower-like g-C3N4/ZnFe2O4 mesoporous hollow microspheres, in which two-dimensional (2D) g-C3N4 nanolayers were loaded onto the surface of ZnFe2O4 hollow microspheres, were constructed by a simple solid phase reaction. The effect of the g-C3N4 concentration on the structure, morphology and gas-sensing performance of the g-C3N4/ZnFe2O4 composites had been explored. On the basis of gas sensitivity test results, the composites owned lower working temperature (160 ℃) and better selectivity toward TEA in comparison with pure ZnFe2O4. Notably, the sensor based on the g-C3N4/ZnFe2O4-15 hollow microspheres (adding 15 ml of g-C3N4 aqueous solution) exhibited outstanding sensing properties, including superior response (18.3) toward 100 ppm TEA at optimum work temperature of 160 ℃, speedy response-recovery time (33, 30 s) and outstanding stability. And the sensor maintained high response of 4.3 to low concentration TEA (5 ppm). The improved gas-sensing performance of the composites could be attributed to the porous ZnFe2O4 hollow microspheres loaded by 2D g-C3N4 nanolayers with large specific surface area and the heterostructure formed between them. Hence, a potential application of the g-C3N4/ZnFe2O4 microspheres might be achieved in detecting TEA at a low optimum work temperature.

Rhombic dodecahedron Ce–Co/C composites with porous hollow structure for efficient electromagnetic wave absorption

The excellent electromagnetic wave (EMW) absorption performance of metal organic frameworks (MOFs) has attracted a lot of attention. In this work, zeolitic imidazolate framework-67 (ZIF-67) was synthesized hydrothermally using 2-methylimidazole (2-mIm) as the organic ligand, cobalt nitrate hexahydrate (Co(NO3)2·6H2O) as the cobalt source and methanol (MeOH) as the organic solvent. The ZIF-67 was etched with cerium nitrate hexahydrate (Ce(NO3)3·6H2O), leading to rhombic dodecahedron Ce–Co/C composites with porous hollow structure after thermal annealing. In addition, the effect of the content of Ce(NO3)3·6H2O on EMW absorption performance of the Ce–Co/C composites was studied. Specifically, the sample Ce–Co/C-2 (Ce(NO3)3·6H2O): (ZIF-67 = 1:2) showed optimal EMW performance. For the Ce–Co/C-2 based composite with a filling ratio of 45 wt%, a RLmin reached −64.67 dB at 11.12 GHz with a thickness of 2.21 mm. The promising EMW absorption performance of the porous hollow structure was attributed to its large specific surface area and massive defects, multiple reflection/scattering, improved impedance matching and increased dielectric loss. This work provides a reference improve EMW absorption performance of MOF materials through regulating their microstructures.

Novel TiO2/GO-Al2O3 Hollow Fiber Nanofiltration Membrane for Desalination and Lignin Recovery.

Due to its greater physical–chemical stability, ceramic nanofiltration (NF) membranes were used in a number of industrial applications. In this study, a novel NF membrane was prepared by co-depositing a titanium dioxide (TiO2) and graphene oxide (GO) composite layer directly onto a porous α-Al2O3 hollow fiber (HF) support. An 8 µm-thick TiO2/GO layer was deposited to the surface of α-Al2O3 HF support by vacuum deposition method to produce advanced TiO2/GO-Al2O3 HF NF membrane. Scanning electron microscope (SEM) micrographs, energy dispersive spectrometer (EDS), X-ray powder diffraction (XRD), thermogravimetric analyzer (TGA), porosity, 3-point bending strength, zeta potential analysis, and hydrophilic properties by water contact angle are used for TiO2/GO-Al2O3 HF NF membrane characterization. The results show that the developed membrane’s MWCO ranged from 600 to 800 Da. The water flux, rejection of lignin, and sodium ions were 5.6 L/m2 h·bar, ~92.1%, and ~5.5%, respectively. In a five-day NF process, the TiO2/GO-Al2O3 HF NF membrane exhibits good lignin permeation stability of about 14.5 L/m2 h.

The Hollow Porous Sphere Cell Carrier for the Dynamic Three-Dimensional Cell Culture.

Large-scale mammalian cell culture is essential in cell therapy, vaccine production, and the manufacturing of therapeutic protein drugs. Due to the adherent growth characteristic of most mammalian cell types, the combination of cell carrier and bioreactor is a common choice in large-scale mammalian cell culture. Current cell carriers developed by polymer crosslinking, lithography, or emulsion drops are unable to obtain a structure with uniformed porous structure and porous interior design, which results in an inhomogeneous culture condition for cells and therefore cannot ensure an optimal dynamic culture condition for cell proliferation, matrix production, and cell differentiation. In addition, the fluidic shear stress (a standard mechanical stimulation in bioreactor culture) and inner-carrier velocity (to ensure nutrient transport and waste exchange), which influence cell viability and growth, are not well-controlled/analyzed due to an irregular porous structure with these traditionally synthesized cell carriers. To solve these problems, we designed four types of hollow porous spheres (HPS, 1.0 cm diameter) with different porous structures. To investigate the impacts of porous structure on surface shear stress and inner velocity, computational fluid dynamics (CFD) simulations were conducted to analyze the liquid flow behavior in HPSs, based on which an optimal structure with minimal surface shear stress and best inner velocity was obtained and fabricated using fused deposition modeling three-dimensional (3D) printing technology. Inspired by the industrial large-scale culture system, a novel 3D dynamic culture system was then established using HPSs to seed the cells, which were then placed in a mini bioreactor on a tube roller. CFD analysis showed that under 0.1 m/s water flow, the shear stress at most surface areas from four HPSs was lower than 20 dynes/cm2, which suggests that the HPSs should provide protection against physical stress to the cells living on the scaffold surface. A dynamic cell seeding was developed and refined using the 3D culture system, which increased the 32% seeding efficiency of MC3T3 cells compared to the traditional static cell seeding method. The cell proliferation analysis demonstrated that HPSs could speed up cell growth in dynamic cell culture. The HPS with a honeycomb-like structure showed the highest inner pore velocity (CFD analysis) and achieved the fastest cell proliferation and the highest cell viability. Overall, our study, for the first time, developed a 3D printed HPS cell culture device with a uniformed porous structure, which can effectively facilitate cell adhesion and proliferation in the dynamic cultural environment, thereby could be considered an ideal carrier candidate.

Porous Amorphous Silicon Hollow Nanoboxes Coated with Reduced Graphene Oxide as Stable Anodes for Sodium-Ion Batteries.

Amorphous silicon (a-Si), due to its satisfactory theoretical capacity, moderate discharge potential, and abundant reserves, is treated as one of the most prospective materials for the anode of sodium-ion batteries (SIBs). However, the slow Na+ diffusion kinetics, poor electrical conductivity, and rupture-prone structures of a-Si restrict its further development. In this work, a composite (a-Si@rGO) consisting of porous amorphous silicon hollow nanoboxes (a-Si HNBs) and reduced graphene oxide (rGO) is prepared. The a-Si HNBs are synthesized through “sodiothermic reduction” of silica hollow nanoboxes at a relatively low temperature, and the rGO is covered on the surface of the a-Si HNBs by electrostatic interaction. The as-synthesized composite anode applying in SIBs exhibits a high initial discharge capacity of 681.6 mAh g–1 at 100 mA g–1, great stability over 2000 cycles at 800 mA g–1, and superior rate performance (261.2, 176.8, 130.3, 98.4, and 73.3 mAh g–1 at 100, 400, 800, 1500, and 3000 mA g–1, respectively). The excellent electrochemical properties are ascribed to synergistic action of the porous hollow nanostructure of a-Si and the rGO coating. This research not only offers an innovative synthetic means for the development of a-Si in various fields but also provides a practicable idea for the design of other alloy-type anodes.

Direct CO2 delivery with hollow stainless steel/graphene foam electrode for enhanced methane production in microbial electrosynthesis

Microbial electrosynthesis system (MES) is a promising power-to-gas energy storage technology. Developing high-performance biocathodes is one of the most strenuous efforts in MES and the key factor limiting MES productivity. However, mass transfer limitation has sometimes been observed to occur in electrodes during operation, especially in three-dimensional (3D) electrodes with certain thicknesses. Herein, a porous hollow stainless steel/graphene foam (GF) electrode was developed to facilitate the direct delivery of CO2 to microorganisms colonized on graphene sheets. The 3D GF possesses a layered structure with interconnected pores, providing a high specific surface area for the colonization and proliferation of methanogenic microorganisms. The hollow stainless steel, coupled with the porous GF to form a hybrid electrode, allows efficient CO2 supply within the 3D biocathode and has a positive effect on maintaining a suitable pH for microbial metabolism inside it. This unique biocathode possesses a high biomass loading and thereby achieves a high CH4-production rate of 848.0 ± 124.5 mmol/m2/d at −1.0 V vs Ag/AgCl (3.6-fold higher compared with carbon cloth), while ensuring the Faradaic efficiency of CH4 up to 84.2 ± 7.7 %. The results indicate that developing 3D-network cathodes with CO2 diffusion assistance is an effective approach to enhance the performance of MES.

Controllable growth of coral-like CuInS2 on one-dimensional SiO2 nanotube with super-hydrophilicity for enhanced photocatalytic hydrogen evolution

Designing a semiconductor photocatalyst with a unique structure is crucial for photocatalytic hydrogen evolution. The adsorption of water molecules is considered to be an important link affecting the photocatalytic activity. Nanoconfined water molecules inside the microporous SiO2 nanotube adsorbed on the active sites boosting the photocatalytic hydrogen evolution compared with the bulk water system. Herein, hydrophilic porous SiO2 hollow nanotubes were prepared through electrospinning fiber membranes as templates. CuInS2 nanoparticles were uniformly deposited on porous SiO2 hollow nanotubes to form CuInS2/SiO2 composites. The unique CuInS2/SiO2 hollow nanotube with a coral structure was prepared. A series of characterization results show that CuInS2 supported on porous SiO2 hollow nanotubes has two advantages. On the one hand, SiO2 has excellent hydrophilicity and can be used as a micro water-collecting reactor to reduce mass transfer resistance. On the other hand, SiO2 reduces the particle size of CuInS2, thus improving the utilization rate of light, and inhibiting electron-hole recombination. The CuInS2/SiO2 with a coral structure exhibited the highest hydrogen production rate of 367.00 μmol g−1 h−1 under visible light irradiation (λ ≥ 420 nm), which is 3.1 times than that of CuInS2 powder. This work points out a novel method to enhance photocatalytic hydrogen evolution.

Ultrasensitive photoelectrochemical sensing platform based on heterostructural CuO/NCDs@Au nanocomposites with the efficient photo-induced carrier separation

Heterogeneous composite is considered a valuable material to boost the photo-electrochemical (PEC) properties. Herein, the porous hollow and thin-shell CuO particles were prepared by calcining a Cu-BTC precursor. N-doped carbon dots (NCDs) as both reductor and stabilizer can reduce the Au+ to gain regularly nanoflower NCDs@Au, which further to create type-Ⅱ heterogeneous interface of CuO/NCDs@Au. PEC monitoring results showed that the CuO/NCDs@Au nanocomposite displayed markedly improved photocurrent response than the monocomponent CuO or CuO/NCDs. This outstanding photoelectric property was ascribed to the multiple reflection/scattering effects from the porous hollow structure of CuO particles which led to more photo-induced e−/h+ pairs. The obtained heterostructured CuO/NCDs@Au could magnify synergistically the photocurrent output signal. Ab (antibodies) was accurately immobilized on the CuO/NCDs@Au modified ITO electrode via a facility amidation reaction. Fabricated Ab/CuO/NCDs@Au/ITO PEC sensing platform for AFP (alpha-fetoprotein) detection manifested an enhanced sensitivity (3.32 × 10-4 ng mL−1) with wide linear range (0.001 ∼ 300 ng mL−1), which was superior compared to the electrochemical results. This works developed an excellent heterojunction nanocomposite of CuO/NCDs@Au, which provided well-synthesized strategies for structuring high-performance photocatalysts based on MOFs derivant.

Elaboration of Ni2P@C Composites with Hollow Porous Structure for Enhanced Overall Water Splitting

AbstractThe electrocatalytic water splitting is greatly affected by overpotential, stability, and accessibility of active sites. Designing appropriate active components and tailoring their microstructure are crucial to improve electrocatalytic performance. Herein, using metal organic framework (MOF) as template, novel Ni2P@C composites are prepared as bifunctional catalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The best Ni2P@C‐350 sample has a small onset overpotential (η) of 57 mV, and up to 148 and 285 mV to afford 10 and 250 mA cm–2 for HER. It only needs η = 326 mV at 10 mA cm−2 for OER, better than usual RuO2 electrode. Moreover, Ni2P@C‐350||Ni2P@C‐350 cell can work for overall water splitting more efficiently than common Pt/C||RuO2 cell, running stably within 30 h without obvious degradation. The excellent performance is attributed to its porous structure with easily accessible active sites, short ions transfer path, and superior structural stability, which enable a significant improvement on molecule level, e.g., the turnover frequency (TOF) of Ni2P@C‐350 at η = 250 mV is up to 0.84 s−1, while that of pristine Ni2P is only 0.55 s−1. These results highlight the effect of structure engineering, inspiring for electrode design of HER and OER.

Post-modified porous hollow nanospheres incorporating multiple strategies for comprehensive phosphoproteomics analysis of serum of Alzheimer's disease

Alzheimer's disease (AD), as a neurodegenerative disease, has become a major disease threatening the physical and mental health of the elderly. In order to find potential cost-effective and valuable AD biomarkers from human serum, we developed and designed a post-modified functional nanomaterial denoted as H–CeO2@PEI-Ti with a porous hollow structure modified with polyethyleneimine (PEI) and Ti4+. This post-modified porous hollow nanomaterial integrated multiple enrichment strategies, including immobilized metal ion affinity chromatography (IMAC) and metal oxide affinity chromatography (MOAC) with electrostatic interaction synergy and hydrogen bond assistance was applied to the phosphoproteomics for the first time. The experimental results demonstrated good performance in the enrichment of standard phosphoprotein tryptic digests, such as extremely low detection limit (0.02 fmol), excellent selectivity (1:5000 M ratio of β-casein and BSA), given that the large specific surface area created by the special porous hollow structure. In serum analyses, 49 phosphopeptides corresponding to 31 phosphoproteins were identified in the serum of the normal controls, and 49 phosphopeptides corresponding to 32 phosphoproteins in AD patients. More importantly, some functional items based on Gene Ontology (GO) analysis after enrichment for human serum supported the molecular biological processes that may be related to the pathogenesis of AD, including copper ion binding, heparin binding and retinoid metabolism.