Porous Sol Gel Research Articles

Temperature evolution of organosilicate glass films with organic bridges

Thin porous sol–gel organosilicate glass (OSG) films containing methylene (Me-OSG), ethylene (Et-OSG), or phenylene (Ph-OSG) bridges between Si atoms, along with terminal methyl groups, were spin-coated onto Si wafers. Porosity was generated using the Brij® L4 template. The investigation focused on examining the effects of annealing (200–1000 °C, 30 min) on the properties of the micro/mesoporous films. The changes in the properties of the films during the annealing process at different temperatures are impacted by the evaporation of solvents, condensation reactions, and destruction of the porogen (200–400 °C). Additionally, the degradation of terminal and bridging organic groups has been observed to occur within the temperature range of 200–600 °C. Finally, the films undergo densification through subsequent condensation and viscous sintering within a temperature range of 700–1000 °C. Ph-OSG films demonstrate remarkable resistance to temperatures of ∼400 °C. Additionally, these films exhibit the highest Young's Modulus (YM) and the smallest pore radius (YM ≈ 6.7 GPa and R ≈ 1 nm after 400 °C annealing). It is important to acknowledge that these materials exhibit a relatively hydrophilic nature, significant shrinkage, and higher refractive index (RI) and dielectric constant (k) compared to the Me-OSG and Et-OSG films. Me-OSG films demonstrate the highest hydrophobicity and porosity, along with minimal shrinkage, RI, and k. However, they also possess the largest pore radius (R = 1.7–2.2 nm after undergoing annealing at 400–550 °C). Modeling the concentrations of different species reveals that the predicted changes in concentrations are strongly dependent on the number of hydroxyl groups present on the surface of the pore walls. The decrease in the number and/or polarizability of OH groups leads to an increased impact of other species on the dielectric constant, resulting in higher computed values.

3D Printing of Macro Porous Sol-Gel Derived Bioactive Glass Scaffolds and Assessment of Biological Response.

3D printing emerged as a potential game-changer in the field of biomedical engineering. Robocasting in particular has shown excellent capability to produce custom-sized porous scaffolds from pastes with suitable viscoelastic properties. The materials and respective processing methods developed so far still need further improvements in order to obtain completely satisfactory scaffolds capable of providing both the biological and mechanical properties required for successful and comprehensive bone tissue regeneration. This work reports on the sol-gel synthesis of an alkali-free bioactive glass and on its characterization and processing ability towards the fabrication of porous scaffolds by robocasting. A two-fold increase in milling efficiency was achieved by suitably adjusting the milling procedures. The heat treatment temperature exerted a profound effect on the surface area of mesoporous powders. Robocasting inks containing 35 vol.% solids were prepared, and their flow properties were characterized by rheological tests. A script capable of preparing customizable CAD scaffold geometries was developed. The printing process was adjusted to increase the technique’s resolution. The mechanical properties of the scaffolds were assessed through compressive strength tests. The biomineralization ability and the biological performance were assessed by immersing the samples in simulated body fluid (SBF) and through MTT assays, respectively. The overall results demonstrated that scaffolds with macro porous features suitable for bone ingrowth (pore sizes of ~340 μm after sintering, and a porosity fraction of ~70%) in non-load-bearing applications could be successfully fabricated by 3D printing from the bioactive glass inks. Moreover, the scaffolds exhibited good biomineralization activity and good biocompatibility with human keratinocytes, suggesting they are safe and thus suited for the intended biomedical applications.

Sol-Gel Thin Film Processing for Integrated Waveguide Sensors

Integrated opto-chemical sensors present great advantages in comparison to the current lab equipment. They bring portability, reduced costs, facilitate in-situ measurements, as well as largely reduced sample volumes. In this quest, standard processing protocols over established materials, such as silicon nitride, silicon, silicon dioxide, titanium oxide, and even a wide variety of polymers have so far been the key toward on-chip devices. However, if very specific materials in terms of composition and tailored properties are required, the deposition via a solution represents a viable alternative. In this review, we highlight the role of sol-gel chemistry and top-down processing of sol-gel thin film layers in the design of waveguide-based optical sensors. In particular, we stress the advantages of porous sol-gel based materials as a new approach to increase sensitivity and selectivity, first when used as claddings, and, more recently, as waveguides with enhanced light–analyte interaction. We finally discuss the future perspectives of such devices to increase specificity in complex matrices, which is of utmost importance for bio-sensing.

Ecological formulation for improving resveratrol stability and release in aqueous environment

Resveratrol (RES) is a naturally occurring product with numerous biological activities. Despite its potential benefits, its use is limited due to its low aqueous stability and solubility in its native form. The porous sol–gel silica materials which are able to entrap different organic molecules represent new studied release carriers. The aim of this work was to generate a solid matrix to encapsulate RES ensuring protection, increased solubility and release in solutions. A non-toxic ingredient, namely β-cyclodextrin (β-CD), able to form inclusion complexes (ICs) with RES has been used. Ecological formulations have been processed by entrapping the RES containing ICs in silica matrices obtained from a silica colloidal sol by the aqueous route of the sol–gel method. Characterization methods (DSC, FTIR, UV–Vis, fluorescence studies, SEM) have evidenced the presence of RES–β-CD inclusion complex in the silica powder, RES stability in the matrix and its release in aqueous and organic solutions, and the morphology of the carrier. An evaluation of the antioxidant activity of RES in the present formulation was performed by the chemiluminescence assay and RES release profile in aqueous solutions was obtained by HPLC–MS. The resulted materials can find applications in different domains.

Mixed-mode fabric phase sorptive extraction of multiple tetracycline residues from milk samples prior to high performance liquid chromatography-ultraviolet analysis

Herein, a new extraction mode of classical fabric phase sorptive extraction (FPSE), namely mixed-mode strong cation exchanging FPSE is presented and evaluated for the first time for the determination of tetracycline residues in milk, after protein precipitation. FPSE is a microextraction technique characterized by high chemically stable sorbent, higher analyte retention capacity and faster analyte diffusion capability, where the target analytes interact with the extraction sorbent during the pre-treatment process via a plethora of intermolecular/interionic interactions exerted by different functional moieties implanted on the sponge-like porous sol–gel sorbent network. Subsequently, the selectively retained analytes are eluted using a small volume of solvent system. A novel extraction membrane containing sol–gel C18/propyl sulfonic acid, a mixed mode sorbent consisting of neutral, C18 and strong cation exchanger, propyl sulfonic acid (C3H6SO3−) coated on 100% cotton cellulose fabric substrate was designed, synthesized, characterized and evaluated for the selective isolation of four tetracycline antibiotic residues from milk samples.For quantitative analysis, high performance liquid chromatography coupled with a UV detector (at 350 nm) was used. The method was validated according to the 2002/657/EC decision with regards to linearity, selectivity, stability, limits of detection and quantitation (LOD/LOQ), decision limit, detection capability, trueness, precision and ruggedness, according to the Youden’s test. Recoveries ranged between 88.9 and 122.4%, while the LOD and LOQ were obtained at 15 μg kg−1 and 50 μg kg−1, respectively. Finally, the composite analytical method was applied to monitor the presence of residual tetracyclines in milk samples purchased from a local Greek market.

All niobia Bragg stacks for optical sensing of vapors

Vapor responsive all Nb2O5 Bragg stacks were prepared using spin-coating of alternating dense and porous films with quarter-wavelength thickness. The required porosity in the films was achieved by soft-templating method using micellar solution of Pluronic copolymer as an organic template. The surface morphology and structure of the films were studied by transmission electron microscopy and selected area electron diffraction, respectively, while optical characterization was performed by combination of ellipsometric and reflectance measurements. Vapor sensing response of the films was tested by reflectance measurements of the samples prior to and after exposure to acetone vapors selected as probe molecules. Incorporation of “defect” layer in the multilayered structures was firstly simulated theoretically and then realized experimentally aiming at improvement of the optical response to volatile organic compounds. Furthermore, the potential of all niobia stacks consisting of alternating dense and porous sol–gel Nb2O5 films as chemical sensors with optical read-out is demonstrated and discussed.

Ferricyanide Confined in a Protonated Amine-Functionalized Silica Film on Gold: Application to Electrocatalytic Sensing of Nitrite Ions

ABSTRACTAn amine-functionalized porous sol–gel silica film was shown to be an effective platform to immobilize small anionic redox mediators of high solubility on solid electrodes by electrostatic interaction. The highly soluble mediator hexacyanoferrate was used as a model. The film was grown and firmly anchored on a gold electrode surface via thiol groups of a self-assembled monolayer of (3-mercaptopropyl)trimethoxysilane. Film growth and thickness were controlled by electrochemical modulation of pH at the electrode/solution interface in a sol of a hydrolyzed solution of tetraethoxysilane and 3-[2-(2-aminoethylamino)ethylamino]propyltrimethoxysilane by the application of a negative potential to the electrode. Protonation of the amine groups made the amine-functionalized surface useful to immobilize hexacyanoferrate on gold. Thus, the immobilization is pH dependent, being highly effective in strongly acidic medium. Cyclic voltammetry and scanning electron microscopy were used to characterize the film and to optimize the experimental conditions. The stability of the film was demonstrated by applying the catalytic properties of the hexacyanoferrate containing surface for nitrite sensing using a flow injection analysis (FIA) system. Under the optimized conditions, the sensor exhibited high sensitivity, low detection limit, easy handling, and stability with a linear range from 1.0 to 40.0 µmol L−1 and a detection limit of 0.53 µmol L−1 based on a signal-to-noise ratio of 3. The sensor was successfully applied to nitrite determination in water samples using FIA with excellent recoveries.

A Novel Protocol to Monitor Trace Levels of Selected Polycyclic Aromatic Hydrocarbons in Environmental Water Using Fabric Phase Sorptive Extraction Followed by High Performance Liquid Chromatography-Fluorescence Detection

Fabric phase sorptive extraction (FPSE) combines the advanced material properties of sol–gel derived microextraction sorbents and the flexibility and permeability of fabric to create a robust, simple and green sample preparation device. It simultaneously improves the extraction sensitivity and the speed of the extraction by incorporating high volumes of sponge-like, porous sol–gel hybrid inorganic–organic sorbents into permeable fabric substrates that are capable of extracting target analytes directly from both simple and complex aqueous sample matrices. For the first time, this technique was applied to the trace-level determination of selected polycyclic aromatic hydrocarbons (PAHs) in environmental water samples using a non-polar sol–gel C18 coated FPSE media. Several extraction parameters were optimized to improve the extraction efficiency and to achieve a high detection sensitivity. Validation tests of spiked samples showed good linearity for four selected PAHs (R2 = 0.9983–0.9997) over a wide range of concentrations (0.010–10 ng/mL). Limits of detection (LODs) and quantification (LOQs) were measured at pg/mL levels; 0.1–1 pg/mL and 0.3–3 pg/mL, respectively. Inter- and intra-day precision tests showed variations of 1.1%–4.1% for four selected PAHs. Average absolute recovery values were in the range of 88.1%–90.5% with relative standard deviations below 5%, surpassing the values predicted by the recovery prediction model. Finally, the developed FPSE-HPLC-FLD protocol was applied to analyze 8 environmental water samples. Out of four selected PAHs, fluoranthene (Flu) and phenanthrene (Phen) were the most frequently detected in four samples, at concentrations of 5.6–7.7 ng/mL and 4.1–11 ng/mL, respectively, followed by anthracene (Anth) and pyrene (Pyr) in two samples. The newly developed FPSE-HPLC-FLD protocol is simple, green, fast and economical, with adequate sensitivity for trace levels of four selected PAHs and seems to be promising for routine monitoring of water quality and safety.

The Preparation of Porous Sol-Gel Silica with Metal Organic Framework MIL-101(Cr) by Microwave-Assisted Hydrothermal Method for Adsorption Chillers.

Metal organic framework (MOF) of MIL-101(Cr)-Silica (SiO2) composites with highly mesoporous and uniform dispersions were synthesized by a microwave-assisted hydrothermal method followed by the sol-gel technique. Water vapor adsorption experiments were conducted on the MIL-101(Cr)-SiO2 composites for industrial adsorption chiller applications. The effects of MIL-101(Cr)-SiO2 mixing ratios (ranging from 0% to 52%), the surface area and amount of Lewis and Brønsted sites were comprehensively determined through water vapor adsorption experiments and the adsorption mechanism is also explained. The BET and Langmuir results indicate that the adsorption isotherms associated with the various MIL-101(Cr)-SiO2 ratios demonstrated Type I and IV adsorption behavior, due to the mesoporous structure of the MIL-101(Cr)-SiO2. It was observed that the increase in the amount of Lewis and Brønsted sites on the MIL-101(Cr)-SiO2 composites significantly improves the water vapor adsorption efficiency, for greater stability during the water vapor adsorption experiments.

Performance and durability of broadband antireflection coatings for thin film CdTe solar cells

Light reflection from the glass surface of a photovoltaic (PV) module is a significant source of energy loss for all types of PV devices. The reflection at the glass and air interface accounts for ∼4% of the total energy. Single layer antireflection coatings with sufficiently low refractive index have been used, such as those using magnesium fluoride or porous silica, but these are only effective over a narrow range of wavelengths. In this paper, the authors report on the design, deposition, and testing of multilayer broadband antireflection coatings. These coatings reduce the weighted average reflection over the wavelength range used by thin film CdTe devices to just ∼1.22%, resulting in a 3.6% relative increase in device efficiency. The authors have used multilayer stacks consisting of silica and zirconia layers deposited using reactive magnetron sputtering. Details of the stack design, sputter deposition process parameters, and the optical and microstructural properties of the layers are provided. Antireflection coatings on glass exposed to the outdoors must not degrade over the lifetime of the module. A comprehensive set of accelerated environmental durability tests has been carried out in accordance with IEC 61646 PV qualification tests. The durability tests confirmed no damage to the coatings or performance drop as a result of thermal cycling or damp heat. All attempts to perform pull tests resulted in either adhesive or substrate failure, with no damage to the coating itself. The coatings also passed acid attack tests. Scratch resistance, abrasion resistance, and adhesion tests have also been conducted. The optical performance of the coatings was monitored during these tests, and the coatings were visually inspected for any sign of mechanical failure. These tests provide confidence that broadband antireflection coatings are highly durable and will maintain their performance over the lifetime of the solar module. All dielectric metal-oxide multilayer coatings have better optical performance and superior durability compared with alternative single layer porous sol–gel coatings. Thin film CdTe devices are particularly problematic because the antireflection coating is applied to one side of the glass, while device layers are deposited directly on to the opposite glass surface in the superstrate configuration. In thin film CdTe production, the glass is exposed to high temperature processes during the absorber deposition and the cadmium chloride activation treatment. If glass precoated with a broadband antireflection coating is to be used, then the coating must withstand temperatures of up to ∼550 °C. Surprisingly, our studies have shown that multilayer silica/zirconia antireflection coatings on soda lime glass remain unaffected by temperatures reaching 600 °C, at which point mild crazing is observed. This is an important observation, demonstrating that low cost glass, which is preprocessed with a broadband antireflection coating, is directly useable in thin film CdTe module production.

Carbon nanospheres covalently modified with polydimethylsiloxane on a porous sol–gel support for use in headspace solid-phase fiber microextraction of BTEX

Carbon nanospheres were covalently modified with hydroxy-terminated poly(dimethylsiloxane) to give a new sorbent (referred to as CNS-PDMS). It was applied as the extraction phase in a sol–gel based solid-phase microextraction fiber for benzene, toluene, ethylbenzene and o-xylene (BTEX). Due to the unique properties of CNS and the performance of the sol–gel coating technology, this fiber possesses a porous surface, a long operational lifespan (at least 200 times), and high thermal stability (up to 350°C). Its extraction capability is higher than that of commercial polydimethylsiloxane (PDMS) and polydimethylsiloxane/divinylbenzene (PDMS/DVB) fibers. Following desorption, the BTEX were quantified by GC with FID detection. The detection limits (at an S/N ratio of 3) range from 1 to 10 pg mL−1, and the limits of quantification (at an SNR of 10) are between 3 and 30 pg mL−1. The repeatability of a single fiber (for n = 5) is between 3.9 and 6.3%, and the fiber-to-fiber reproducibility (for n = 3) ranges from 5.3 to 8.2%, respectively. The relative recoveries in the real water samples ranged from 92.5% to 99.5%. The results demonstrate that the method is highly effective for analyzing BTEX in water samples.

Luminescent properties of composite scintillators based on PPO and o-POPOP doped SiO2 xerogel matrices

New composite scintillation detectors were obtained by incorporation of PPO and o-POPOP organic scintillators into porous sol–gel silica matrices. Composites possess high photoluminescence intensity and decay time in nanosecond range. The absolute light yield of composite scintillators at excitation by alpha-radiation is about 4000–5000 photons/MeV and the pulse–height resolution is about 30%. The investigations of time-resolved luminescence of composites performed under excitation by synchrotron radiation in the 3.7–25eV range have shown that the non-radiative energy transfer between host matrix and dopant molecules occurs via singlet states of SiO2 oxygen-deficient centers.

Fluorescence quenching of rhodamine 6G by 1,3,5-Trinitroperhydro-1,3,5- triazine entrapped in porous sol–gel silica

Fluorescence quenching of laser dye rhodamine 6G by codoping 1,3,5-Trinitroperhydro-1,3,5-triazine (RDX) in porous sol–gel silica is reported. It was found that the fluorescence intensity of rhodamine 6G decreases with increase in the concentration of RDX. Both the samples, predoped cylindrical shaped and postdoped thick film on glass substrate with RDX show the similar fluorescence quenching behavior. Emission spectra show slight red shifting with the increase in RDX concentration. An electron-transfer donor–acceptor mechanism is proposed for the observed fluorescence quenching. On the basis of these results, candidature of dye doped porous sol–gel silica as a sensor for explosive detection seems to be promising.

Characterizing Solvent Dynamics in Nanoscopic Silica Sol–Gel Glass Pores by 2D-IR Spectroscopy of an Intrinsic Vibrational Probe

Porous sol–gel matrices were synthesized with IR-active Si–H vibrational chromophores integrated into the silica network. The Si–H vibrational mode was found to be highly accessible to solvents within the nanoscopic pores. Vibrational solvatochromism of the silane vibration was controlled largely by interactions between infiltrating solvents and the oxygen and hydroxide sites in the silica. Exchanging solvents in the silica matrices produced reversible solvatochromic shifts in some cases but led to irreversible shifts when strongly interacting solvents were tested, suggesting that a layer of solvent was not exchangeable. 2D-IR spectroscopy was used to monitor spectral diffusion and extract the homogeneous line widths of the Si–H mode for a range of infiltrating solvents as well as solvent-free aerogel samples. It was demonstrated that the silane vibration is sensitive to the nature of the infiltrating solvent, making these vibrationally active sol–gel films a general platform for solvent dynamics in nanoscopic confined volumes.

The Influence of the Temperature on Positron Annihilation Lifetime Spectra in Porous Sol-Gel Glass Doped with Ag Nanoparticles

Silver nanoparticles with continuous size distribution from 10 to 20 nm were incorporated into porous glass produced using sol gel technique. Positron annihilation lifetime spectroscopy was used to compare obtained material with an undoped reference glass. The positron annihilation lifetime spectroscopy measurement were made in a broad temperature range (from −180 ◦C to 200 ◦C). The experimental lifetime values were compared with the predictions of the extended Tao Eldrup model of the temperature range. Experimental results for the reference material were in agreement with the model, except for a small discrepancy at low temperatures. In doped material substantial changes and non-monotonous temperature dependences of intensity and lifetime values were observed. Heating the material to 200 ◦C resulted in reorganization of the material structure.

Nanostructured antireflective bilayers: Optical design and preparation

We show different methods for tailoring and fabrication of various cost-effective antireflective nanocoatings on transparent and non-transparent substrates. The main purpose was to prepare coatings with decreased reflectance in the full visible wavelength range using simple wet layer deposition techniques. Structure of coatings was designed by optical simulations applying simplified calculations. The refractive index of substrates was also considered for the calculations. The advantageous optical properties were achieved by bilayered structures combining compact and porous sol–gel derived oxide layers and nanoparticulate films. The bilayered structures enhance the flexibility of design by not only the selection of the layer thicknesses but also by different ways of adjusting the effective refractive index of the layers. Furthermore, chemical stability of the coatings was also investigated. The optical and structural properties of prepared films and bilayered coatings were studied by UV–vis spectroscopy and scanning electron microscopy, respectively. The transmittance of coated glass substrates was above 97.5%, while the reflectance of coated silicon substrates was below 4% between 450 nm and 900 nm.

Electrochromic Properties of Sol-Gel Synthesized Macroporous Tungsten Oxide Films Doped with Gold Nanoparticles

Macroporous tungsten oxide thin films were prepared by using a polystyrene microsphere template and the peroxitungstic acid precursor. Gold nanoparticles were introduced into the tungsten oxide film by two different methods, either in the polystyrene template, through a self-assembly process, or they were cast on the surface of the annealed film. Raman imaging experiments showed an enhancement effect of the intensity of the major tungsten oxide bands by the gold nanoislands. The electrochromic properties of gold-doped macroporous tungsten oxide are described and compared to those of the standard porous sol-gel film. The films with gold nanoparticles on the surface of the tungsten oxide film were found to have better electrochromic properties than the standard sol-gel tungsten oxide films and the ones doped with gold in the polystyrene template. The diffusion coefficients of protons in the gold-doped tungsten oxide films were determined from both Cyclic Voltammetry (CV) and Electrical Impedance Spectroscopy (EIS) measurements. The results indicate a faster diffusion of the proton in the porous film, compared with a compact tungsten oxide film. The model that evolves from the EIS data, involves fast charge transfer rates at the electrolyte/tungsten oxide film interface. The results demonstrated an enhancement of the coloration efficiency of the macroporous tungsten oxide films with Au nanoparticles on the surface of the film. The possible involvement of plasmon resonance of Au nanoparticles in the electrochromic process is discussed.

Phase Transformation and Charge Transfer in Heavily Iron Ion Doped Titanium Oxide and Oxynitride Nanocolloids

Porous sol–gel generated TiO2 nanocolloids and their corresponding oxynitrides TiO2–xNx are investigated to evaluate the effects that accompany doping with iron (FeII) ions at high doping concentrations. The introduction of FeII at higher concentrations leads to an anatase-to-rutile conversion at room temperature for the seeded oxynitride nanocolloids and to a less crystalline state in the subsurface and bulk as suggested by Raman spectroscopy. Combinations of core level and valence band photoelectron spectroscopy are correlated with the results of density functional theory (DFT) calculations to demonstrate a facile charge transfer from FeII to TiIV, producing TiIII and FeIII, and subsequently the transformation of FeII + TiIII to FeIII + TiII. This process is associated with the detectable formation of Ti(III) and Ti(II) at the surface of the titania-based nanoparticles. With significant visible light absorption, the photocatalytic activities of the iron-seeded titania systems are comparable to that of the iron-doped oxynitride TiO2–xNx as a function of doping concentration. The observations reported herein suggest that the anatase-to-rutile phase transformation and the enhancement of electron transfer can control the visible-light catalytic activity within the doped nanoparticles to form FeII/FeIII-codoped TiO2 nanocolloids.

RhEPO/EPO discrimination with ultrasensitive electrochemical biosensor based on sandwich-type nano-Au/ZnO sol–gel/nano-Au signal amplification

This research established a non-labeled electrochemical biosensor for discrimination of recombinant human erythropoietin (rhEPO) and endogenous erythropoietin (EPO). We prepared a glassy carbon electrode (GCE) modified by a unique sandwich-like nano-Au/ZnO sol–gel/nano-Au compound membrane for signal amplification. The porous sol–gel structure facilitates protein activity maintenance and thermostability. Nano-Au is characterized by a large specific surface area, high surface activity, high absorbability, and good electro-conductivity and biocompatibility. By combining the advantages of both ZnO sol–gel and nano-Au, the amount of erythropoietin receptor (EPOR) increased substantially, and electron transfer of EPOR protein and electrode surface increased accordingly. In the present study, the effects of experimental conditions such as nano-Au electrodeposition time and nano-Au concentration were investigated by cyclic voltammetry, and the process of GCE modification was characterized electrochemically. We successfully developed a new method for electrochemical detection of trace rhEPO/EPO. More importantly, the response current change (ΔI) of the nano-Au/ZnO sol–gel/nano-Au modified GCE increases 3-fold when compared with that of the unmodified electrode and the sensor detection sensitivity increases significantly. In conclusion, this electrochemical biosensor is simple to prepare and allows fast, accurate, and specific detection of trace rhEPO in clinical monitoring and stimulant discrimination.

Mitigation of the delamination of LSM anode in solid oxide electrolysis cells using manganese-modified YSZ

Manganese-modified yttria-stabilized zirconia (Mn-YSZ) has been used to suppress interfacial degradation and anode delamination during short term (∼200 h) electrochemical testing of solid oxide electrolysis cells (SOEC). Two fabrication methods have been used for YSZ surface modification: solid state diffusion of manganese into YSZ substrate and sol–gel coating of a Mn-YSZ layer on YSZ substrate. Both the solid state diffusion and sol–gel coating methods stabilized the electrical performance; however, anode delamination was mitigated only by the sol–gel method. Post-test analysis indicates reduction in the formation of lanthanum zirconate on the Mn-modified electrolyte surface. It is proposed that the presence of the porous sol–gel coating prevents high pressure oxygen build up and results in the mitigation of the anode delamination.