High Sulfur Resistance Research Articles

Synergistic effects of multi-walled carbon nanotubes and Mn0.4Cu0.6Fe2O4 on mercury removal with high efficiency and sulfur resistance

Although ferrite-based adsorbents are the potential mercury removal materials for the high thermal stability, they usually suffer from a low efficiency in flue gas environment, especially under SO2 condition. In the present paper, the multi-walled carbon nanotubes (MWCNTs) are utilized to improve the adsorption capacity of the Mn0.4Cu0.6Fe2O4 adsorbents as well as inhibit the influence of flue gas composition. The influences of temperature, adsorbent type and the flue gas composition on Hg0 removal efficiency are evaluated by experiments. The physical adsorption property of MWCNTs provides a platform for Hg0 oxidation by Mn0.4Cu0.6Fe2O4. The synergistic effect between MWCNTs and Mn0.4Cu0.6Fe2O4 enhances the mercury removal efficiency as well we the sulfur resistance. The results find that the adsorbent of Mn0.4Cu0.6Fe2O4 containing 14 % MWCNTs has a high mercury removal efficiency of 95.6 % at 120 °C even under 1000 ppm SO2 concentration. The kinetic behaviors of adsorbent adsorption are analyzed by theoretical models. The mechanisms of porous carbon-containing modifier to improve the mercury removal performance of Mn0.4Cu0.6Fe2O4 are explored carefully. The present ferrite-based adsorbent exhibits promising prospects for the practical industrial applications of the low temperature mercury removal from coal-fired flue gas.

Selenium-modified activated coke: a high-capacity and facile designed Hg0 adsorbent for coal-fired flue gas.

The substantial amount of mercury emissions from coal-fired flue gas causes severe environmental contamination. With the Minamata Convention now officially in force, it is critical to strengthen mercury pollution control. Existing activated carbon injection technologies suffer from poor desulfurization performance and risk secondary-release risks. Therefore, considering the potential industrial application of adsorbents, we selected cost-effective and readily available activated coke (AC) as the carrier in this study. Four metal selenides-copper, iron, manganese, and tin-were loaded onto the AC to overcome the application problems of existing technologies. After 120min of adsorption, the CuSe/AC exhibited the highest efficiency in removing Hg0, surpassing 80% according to the experimental findings. In addition, the optimal adsorption temperature window was 30-120°C, the maximum adsorption rate was 2.9 × 10-2mg·g-1·h-1, and the effectiveness of CuSe/AC in capturing Hg0 only dropped by 5.2% in the sulfur-containing atmosphere. The physicochemical characterization results indicated that the AC surface had a uniform loading of CuSe with a nanosheet structure resembling polygon and that the Cu-to-Se atomic ratio was close to 1:1. Finally, two possible Hg0 reaction pathways on CuSe/AC were proposed. Moreover, it was elucidated that the highly selective binding of Hg0 with ligand-unsaturated Se- was the key factor in achieving high adsorption efficiency and sulfur resistance in the selenium-functionalized AC adsorbent. This finding offers substantial theoretical support for the industrial application of this adsorbent.

Regeneration of a sulfur-poisoned selective catalytic reduction catalyst at ambient conditions

Despite the high sulfur resistance of vanadia-titania catalysts with physically mixed zeolite in the selective catalytic reduction of NOx (SCR), their regeneration is still challenging because it typically requires a large amount of energy or hazardous chemicals. This paper proposes an innovative regeneration strategy for prolonging the lifetime of the sulfur-poisoned catalyst. Our spectroscopic results revealed that the adsorbed water in the catalyst dissolves the deactivating material, ammonium bisulfate (ABS). We developed a regeneration protocol based on this finding, which was facilitated by dissolution of ABS in water adsorbed on the catalyst during the exposure to humid air at ambient temperature. The superior hydrophilic nature of zeolite resulted in a different water content between two physically mixed domains, promoting ABS migration from the vanadia active sites to zeolite and thus recovering the catalytic activity. This strategy is beneficial for the development of energy-efficient and environmentally friendly SCR systems.

Hydrolysis of Carbonyl Sulfide in Blast Furnace Gas Using Alkali Metal-Modified γ-Al2O3 Catalysts with High Sulfur Resistance.

A carbonyl sulfide (COS) hydrolysis catalyst can play an efficient role in blast furnace gas (BFG), but the life of the catalyst is greatly shortened due to the presence of O2 and H2S in the atmosphere, so improving the sulfur resistance of the catalyst is the key to application. In this work, alkali metals Na and K modified γ-Al2O3 catalysts to improve COS hydrolysis efficiency and sulfur resistance by adding an alkaline center. Compared with γ-Al2O3 catalysts, the COS hydrolysis efficiency of the modified catalysts in the experiment was improved by 12% in the presence of H2S and O2. The main cause of catalyst sulfur poisoning is the presence of O2, which intensifies both the total amount of sulfur deposition and the proportion of sulfate. It is found that the NaOH/Al2O3 catalyst shows better sulfur resistance than the KOH/Al2O3 catalyst for two reasons: first, the support of Na can significantly improve the medium-strong alkaline site, which is the adsorption site of H2S. This is equivalent to increasing the "sulfur capacity" of H2S adsorption and reducing the impact of sulfur deposition on the main reaction. Second, the elemental sulfur is more easily produced on the NaOH/Al2O3 catalyst, but the sulfur is further oxidized to sulfate and sulfite on the KOH/Al2O3 catalyst. The molecular diameter of elemental sulfur is smaller than that of sulfate. Therefore, the NaOH/Al2O3 catalyst has better sulfur resistance.

Oxidation of CO and slipped NH3 over a WS2-Loaded Pt/TiO2 catalyst with an extended reaction temperature range

The recent tightening of emission regulations aims to reduce the release of CO and slipped NH3 with industrial flue gas, necessitating the development of improved CO and NH3 oxidation catalysts, as conventional Pt catalysts are easily poisoned by the SO2 present in flue gas. In particular, the reaction temperature range of existing Pt/TiO2 catalysts and their resistance to sulfur poisoning can be improved by enhancing Pt dispersion through modification with WS2. This study examined the ability of WS2-doped Pt/TiO2 catalysts prepared using different WS2 loadings (3.6 and 5 wt%) at various calcination temperatures (300, 400, and 500 °C) to promote the oxidation of CO and NH3 in the absence and presence of SO2. The partial conversion of WS2 to WO3 at high calcination temperatures is found to be of key importance for securing high catalyst performance. The optimal catalyst exhibits high oxidation activity and sulfur resistance at low temperatures, achieving CO and NH3 oxidation efficiencies of ≥85% and 100%, respectively, at an SO2 content of 100 ppm and 280 °C.

Phosphotungstic acid-promoted Mn-Fe bimetal oxide with high sulfur resistance for low-temperature selective catalytic reduction of nitrogen oxides with NH3

The catalysts with low-temperature activity and high sulfur resistance are expected in the denitration application. To obtain an efficient and eco-friendly catalyst for NOx abatement, phosphotungstic acid (HPW) promoted Mn-Fe bimetal oxide composites were constructed by colloidal solution combustion synthesis followed by the impregnation method. Their catalytic mechanism and activity at low temperature analyzed in detail by XRD, BET, SEM, XPS, H2-TPR, NH3-TPD and in situ DRIFTS characterizations. The results show that the large surface area and uniform mesoporous of Mn-Fe oxide contributed to the dispersion of HPW nanoparticles. The highly dispersed HPW can regulate the surface acidity and redox property of the catalyst. The Mn0.25Fe0.75-HPW50 compound combined the redox property of mesoporous Mn-Fe oxide and the acidic advantage of HPW showed a wider operating temperature window (125–400 °C, NOx conversion >94%) with higher N2 selectivity and SO2 resistance. Langmuir-Hinshelwood (L-H) and Eley-Rideal mechanisms (E-R) coexist in the SCR reaction. This work can provide a strategy for designing composite materials with low-temperature activity and high sulfur resistance. The developed porous HPW-promoted Mn-Fe oxide would be a promising catalyst candidate for NOx removal.

Insights into the different catalytic behavior between Ce and Cr modified MCM-41 catalysts: Cr2S3 as new active species for CH3SH decomposition

High sulfur resistance and high stability of catalysts are crucial for the catalytic decomposition of sulfur-containing volatile organic compounds. In this work, compared to 5Ce-MCM-41, the 5Cr-MCM-41 catalyst exhibited ultra-stability (no activity loss at 600 h) and higher sulfur resistance. The physical structure and chemical characteristics of the catalysts were analyzed by XRD, H2-TPR, NH3-TPD, CO2-TPD, XPS, and TEM. Combining the characterization results, we found that the 5Cr-MCM-41 catalyst presented outstanding catalytic performance due to superior reducibility and appropriate acidity, which results in the conversion of most of the C and S elements in the CH3SH to the gas-phase coke- and sulfur-containing products rather than accumulating on the catalyst surface. Meanwhile, the catalytic performance, reaction path, and deactivation mechanism of rare earth metal (Ce) and transition metal (Cr) modified MCM-41 catalysts were systematically investigated by in situ DRIFTS and DFT calculations. Additionally, a new active phase (sulfide state Cr2S3) was proposed and proved via accurately designed experiments, which plays a significant role in the collaborative removal of CH3SH with hexavalent chromium (Cr(VI)). These findings are beneficial for designing high sulfur resistance catalysts for the removal of CH3SH and other sulfur-containing products.

Trace Co doping improves NH3-SCR performance and poisoning resistance of Ce-Mn-based catalysts

Trace amounts of Co-doped Ce-Mn-based metal oxide catalysts with various applications were synthesized by a simple redox method. When the molar fraction of doped Co was 3 %, the catalyst possessed comparatively high contents of adsorbed oxygen species (Oads), Mn4+, Ce3+, and Co3+, and exhibited promising catalytic performance. C1M3C-3 % had a wide denitrification temperature window, achieving 80 % NO removal at 87–277 °C and 90 % catalytic combustion of toluene at 171 °C (T90% = 171 °C). Furthermore, the catalyst exhibited satisfactory moisture and sulfur resistance activity and can be regenerated by simple calcination (350 °C, 4 h). The reason for the high sulfur resistance of C1M3C-3 % was investigated in detail and a schematic diagram was provided. The NH3-SCR process was revealed to satisfy the L-H mechanism with the assistance of in situ DRIFTS. This work demonstrated that the Co-doped Ce-Mn-based catalyst had the potential for downstream of soot treatment equipment.

Catalytic combustion of lean methane over MnCo2O4/SiC catalysts: Enhanced activity and sulfur resistance

The simultaneous control of catalytic activity and sulfur resistance is a challenging task for non-noble metal catalysts in the domain of heterogenous catalysis. Herein, by dispersing MnCo2O4 (MCO) nanoparticles on a SiC substrate, we develop a novel catalyst for methane combustion that exhibits excellent low-temperature catalytic activity as well as high sulfur resistance. Strong interactions between SiC and MCO reduce the crystallite size of MCO and increase the specific surface area of the catalyst and the concentration of the active species, namely, Co3+ and surface oxygen species. The 60%MCO/SiC sample shows the highest catalytic activity, with T10, T50, and T90 values of 335, 375, and 444 °C, respectively, at a space velocity of 45,000 mL∙g−1∙h−1. In-situ diffuse reflectance infrared spectroscopy experiments and physicochemical characterizations indicate that the enhancement of catalytic activity is mainly attributed to the abundant adsorbed oxygen and surface Co3+ species in the catalysts that accelerate the formation of carbonate and formic acid species during methane conversion. The 60%MCO/SiC sample also exhibits high sulfur resistance, which is mainly attributed to the inhibiting effect of SiC on the catalyst for bulk sulfate formation. The findings of this study provide insights for the fabrication of catalysts with high activity as well as high sulfur resistance.

Study on the CO-SCR anti-sulfur and denitration performance of V-doped OMS-2 catalysts

A catalyst with high NO conversion rate and good sulfur resistance is the key to CO-SCR. Herein, the V-doped OMS-2 molecular sieves were successfully synthesized through the hydrothermal method. The resulting catalyst was characterized by X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), transmission electron microscope(TEM) and specific surface area analyzer (BET). The results showed that the addition of V increased the average grain size of OMS-2 and the concentration of oxygen vacancies. Meanwhile, V replaced the K site in OMS-2 and participated in the oxidation-reduction reaction together with Mn. Compared with the V0-OMS-2, the NO conversion rate of V0.2-OMS-2 in a sulfur-free environment increased from 60% to 81% at 150 °C and 75%–94% at 300 °C. The NO conversion rate could still maintain as 80% at 300 °C in a sulfur-containing environment.

Efficient mercury removal in chlorine-free flue gas by doping Cl into Cu2O nanocrystals

The low content of hydrogen chloride (HCl) in flue gas is difficult to meet the request of Hg0 removal. Here, a small amount of Cl was doped into the crystal lattice of Cu2O nanocrystals (Cl-Cu2O), presenting excellent Hg0 removal efficiency in chlorine-free coal combustion flue gas. SEM, XRD, BET, and XPS characterizations revealed well crystal morphology and structure of Cl-Cu2O catalyst. Besides, Cl-Cu2O had smaller sizes and higher BET surface area compared with Cu2O. Hg0 removal behaviors were studied using a lab-scale fixed-bed reactor. After doping Cl, Hg0 removal efficiency was improved obviously and could reach nearly 100% above 150 ℃, indicating chlorine incorporated into the catalyst lattice had a better role for Hg0 removal. Besides, gas composition effect on Hg0 removal was analyzed. Cl-Cu2O had high sulfur resistance capacity, and Hg0 removal efficiency can still reach above 90% even at 2000 ppm SO2. O2 played a critical role in the Hg0 removal reaction. Furthermore, a plausible mechanism for Hg0 removal was analyzed. Doping Cl into the lattice of Cu2O nanocrystals was beneficial for the activation of molecular oxygen, and generated reactive oxygen species can further activate Cl to participate in the Hg0 removal reaction.

Catalytic oxidation of CO over Pt/TiO2 with low Pt loading: The effect of H2O and SO2

Anatase TiO2 loaded with 0.1wt.% Pt catalyst (0.1Pt/TiO2-A) was prepared via the impregnation method, and its CO catalytic oxidation activity was investigated. Noteworthy, introduction of H2O into the reaction atmosphere apparently facilitated the catalytic oxidation of CO. Besides, introduction of SO2 inhibited the catalytic oxidation of CO. In presence of H2O and SO2, 0.1Pt/TiO2-A showed outstanding catalytic stability, and X-ray photoelectron spectroscopy (XPS) and thermogravimetric (TG) characterizations suggested that the amount of sulfate species deposited on the 0.1Pt/TiO2-A treated at 230 °C did not increase with time extension, which might be an important reason for the high sulfur resistance of 0.1Pt/TiO2-A. XPS results also demonstrated that the dissociation of H2O led to considerably increase of hydroxyl groups over the catalyst surface. H218O isotope-labeling experiments unambiguously showed that C16O18O was the main product accounting for 88.9%, revealing that the other oxygen atom in the product CO2 was mostly from H2O. Consequently, based on previous researches and our experimental results, the mechanism of H2O promoting CO oxidation on 0.1Pt/TiO2-A catalyst was proposed.

Mineral-derived catalysts optimized for selective catalytic reduction of NOx with NH3

A type of novel mineral-derived catalyst (MDC) composed of vanadium–titanium magnetite and sintering ore was prepared via calcination or acid modification for selective catalytic reduction of nitrogen oxides (NOx) with ammonia (NH3) to reduce the production cost and simplify the preparation process. Characterizations by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) mapping, X-ray photoelectron spectroscopy (XPS) and temperature-programmed reduction of hydrogen (H2–TPR) characterizations were performed to observe the evolution of the physicochemical properties of the mineral catalyst during modification, which were corelated to their catalytic activity. The in-situ DRIFTS was also investigated to discuss the reaction mechanism for different catalysts. The results show that the mineral catalysts with sulfuric acid modification exhibit high NOx conversion (above 90% at 350 °C) and sulfur resistance due to the formation of ferric sulfate species and the presence of Fe3+/Fe2+ and V5+/V4+ couples in the catalysts that results in abundant Brønsted acid sites and promotes the redox properties of catalysts. The in-situ DRIFTS results indicate that the catalysts modified by calcination-pretreatment primarily follow the Langmuir-Hinshelwood (L–H) mechanism where gaseous NO is more easily adsorbed on α-Fe2O3 to form stable nitrates and react with a small number of NH3 species adsorbed on α-Fe2O3, leading to decreased activity. On the other hand, the catalysts modified with acid mainly follow the Eley-Rideal (E–R) mechanism in which adsorbed nitrogen species show less thermal stability and a large amount of adsorbed NH3 on the ferric sulfate species directly react with gaseous NO, resulting in the higher activity.

Superficial Pd nanoparticles supported on carbonaceous SBA-15 as efficient hydrotreating catalyst for upgrading biodiesel fuel

Facile synthesis of superficial Pd nanoparticles supported on carbonaceous SBA-15 (denoted as Pd/@SBA-15) as a new hydrotreating catalyst with enhanced activity and sulfur tolerance was accomplished for the production of partially hydrogenated fatty acid methyl esters (H-FAME), a high-quality biodiesel fuel enriched in monosaturated fatty acid methyl esters (mono-FAME) that can be used in high blends. Characterization, especially high-resolution electron microscopes and temperature-programmed techniques, indicated that the Pd nanoparticles (∼7 nm) formed spontaneously at the superficial area of carbonaceous SBA-15 with a hydrophobic surface and low acidity. In the synthesis of H-FAME using commercial palm oil-derived biodiesel fuel as a feedstock under mild conditions (<100 °C, 1 MPa), this new Pd/@SBA-15 catalyst offered high hydrotreating activity with excellent selectivity toward mono-FAME, especially the cis product, and high sulfur resistance, presumably due to fast diffusion and suitable interactions of the reactant and hydrogenated molecules through superficial Pd nanoparticles on the carbonaceous surfaces as the catalytically active sites. On the other hand, commercial Pd catalysts with Pd nanoparticles randomly impregnated inside the supporting materials showed lower activity in H-FAME synthesis and poorer selectivity toward saturated fatty acid methyl esters as undesirable products and lower sulfur tolerance level per Pd site, demonstrating the superiority of our system.

Optimum design of downhole chokes with high sulfur content and large pressure difference

Natural gas resources are abundant in southwest China, but the exploitation environment with high pressure and sulfur always affects the working performance of downhole chokes, which in turn restricts the output of natural gas. In this paper, a high sulfur resistance fixed downhole choke is designed for high temperature (120°C), high production rate and high pressure difference (105MPa) sand-producing Wells. Through the nozzle discharge model to simulate the flow of the fluid through the nozzle, with Bono Maleev method to predict the hydrate formation conditions of downhole choke for the design of the structure. According to the failure forms of different parts, the materials were optimized, and the high sulfur resistant 3YC51 alloy, hard alloy and wear and corrosion resistant sulfur resistant rubber were selected through the test to improve the service life of the choke in the high sulfur high-pressure gas well and ensure the reliability of the tool. The results of numerical analysis on the tool holder and the pressure test of the Laboratory seal show that the choke designed has a good sealing and pressurization performance in the high temperature and high pressure difference environment of 120°C and 105MPa, and it can realize the function of lowering the pressure at the bottom of the well under this working condition, meeting the feasibility requirements. Through this design, the design and improvement of high sulfur gas well tool and new choke has guiding significance.

Sulfur-Resistant Cu0.7Ni0.3Fe2O4 Catalyst for Removing NO from Diesel Exhausts

The catalyst in the NH3-SCR process for removing NO from diesel exhaust is prone to poisoning by relatively high sulfur contents in diesel in China. The catalyst should have not only favorable catalytic activity for NO removal, but also high sulfur resistance. The spinel-type Cu1−xNixFe2O4 (x = 0–0.5) catalysts with different Ni contents were prepared by sol–gel method using citric acid as complexing agent. The catalytic activities for NO removal in sulfur-free and sulfur-containing (SO2, 0.035%, volume fraction) air were investigated in a fixed bed reactor. Meanwhile, the sulfur resistance was tested in sulfur-containing air. Moreover, the catalysts before and after the reaction were characterized by XRD, SEM, N2-adsorption, EDS, NH3-TPD, FT-IR and XPS technologies, and the mechanism of sulfur poisoning of the catalyst was also discussed. The results showed that when the Ni content was 0.3, the formed Cu0.7Ni0.3Fe2O4 spinel catalyst had the optimal catalytic performance, of which the NO conversion could be 95.87% in sulfur-free air with 5% oxygen content, and it maintained above 90.12% in the sulfur-containing air within 240 min. Characterization results illustrated that sulfur poisoning of catalyst might be caused by many pathways. The introduction of Ni into catalyst could inhibit destruction of the catalyst structure and make the catalyst become more stable in sulfur-containing air and show high sulfur resistance.

SCR Coated DPF for Marine Engine Applications

The combination of a catalytic coating for selective catalytic reduction (SCR) and a diesel particulate filter (DPF) obtains the simultaneous reduction of NOX and particulate matter in a compact exhaust after-treatment system (EATS). A diesel oxidation catalyst (DOC), which is installed upstream to the SCR coated DPF (SDPF), provides the required NO2 for the passive soot regeneration. The layout of this EATS is state of the art for automotive applications. However, the requirements of a marine application, especially the high sulfur resistance, result in a significant development effort. It has been observed that the combination of vanadium-based coatings and DPF substrates made of cordierite lead to a significant deterioration of the SCR performance after different aging procedures. Contrary to this, the combination of DPFs, which consist of silicon carbide, and vanadium-based coatings, reveals a sufficient NOX reduction after aging in addition to the required sulfur resistance. Furthermore, the investigated DOC systems provides a remarkable NO2 generation, which enables the passive soot regeneration in the SDPF system, while using marine distillate fuels with a sulfur content up to 5000 ppm.

Highly stable activated carbon composite material to selectively capture gas-phase elemental mercury from smelting flue gas: Copper polysulfide modification

Gaseous elemental mercury removal from high SO2 flue gas is an urgent environmental problem. In this study, a new sorbent, copper polysulfide modification activated carbon (CuxSy@AC), was synthesized. CuxSy@AC demonstrated better Hg0 capture performance than copper-impregnated (Cu@AC) and sulfur-modified (S@AC) materials. The mercury adsorption capacity of CuxSy@AC from high-concentration SO2 smelting flue gas could reach 3924 μg/g in optimal conditions, and this adsorption capacity was superior to that of common modified sorbents. The physical and chemical characteristics of CuxSy@AC were analyzed through several characterization methods, including X-ray diffraction, Brunauer–Emmett–Teller surface area analysis, scanning electron microscopy, and fourier transform infrared spectroscopy. Thermo-gravimetric and Raman analyses confirmed that CuxSy@AC had high thermal stability and consisted of short-chain sulfur that had a strong affinity to Hg0. Hg0 was physically adsorbed on the material surface. Then, the adsorbed Hg0 bonded with active sulfur in copper polysulfide to form stable HgS, which was confirmed by X-ray photoelectron spectroscopy and temperature-programmed desorption analysis. CuxSy@AC may be a promising sorbent for Hg0 removal from high-SO2-concentration flue gas due to its outstanding Hg0 capture performance and high sulfur resistance, and it may be used as a method to recover mercury resources.

Synergy between a sulfur-tolerant Pt/Al2O3@sodalite core–shell catalyst and a CoMo/Al2O3 catalyst

A remote control model material was developed, which consists of a sulfur-tolerant Pt/Al2O3@sodalite catalyst and a CoMo/Al2O3 catalyst and which combines the concepts of size-selectivity and hydrogen spillover. The Pt/Al2O3@sodalite with core shell structure was prepared by coating a Pt/Al2O3 core with a nanosized sodalite (SOD) shell. The cages of the SOD are sufficiently small (0.3 nm) to exclude the smallest sulfur-containing molecules (hydrogen sulfide, 0.36 nm), while allowing hydrogen molecules (0.289 nm) and atomic hydrogen to diffuse in and out of the cages to allow hydrogen spillover. The Pt/Al2O3@sodalite core–shell material combined with traditional sulfided cobalt molybdenum showed high activity, stability, and high sulfur resistance in the hydrodesulfurization of dibenzothiophene. The Pt/Al2O3@sodalite core–shell material (where hydrogen spillover starts) is used as active hydrogen emission sources, producing active hydrogen and transporting it to the traditional sulfided cobalt molybdenum catalyst (where the spilled over hydrogen is used).

Tailoring SOFC Electrode Microstructures for Improved Performance

AbstractThe key technical challenges that fuel cell developers need to address are performance, durability, and cost. All three need to be achieved in parallel; however, there are often competitive tensions, e.g., performance is achieved at the expense of durability. Stability and resistance to degradation under prolonged operation are key parameters. There is considerable interest in developing new cathodes that are better able to function at lower temperature to facilitate low cost manufacture. For anodes, the ability of the solid oxide fuel cell (SOFC) to better utilize commonly available fuels at high efficiency, avoid coking and sulfur poisoning or resistance to oxidation at high utilization are all key. Optimizing a new electrode material requires considerable process development. The use of solution techniques to impregnate an already optimized electrode skeleton, offers a fast and efficient way to evaluate new electrode materials. It can also offer low cost routes to manufacture novel structures and to fine tune already known structures. Here impregnation methodologies are discussed, spectral and surface characterization are considered, and the recent efforts to optimize both cathode and anode functionalities are reviewed. Finally recent exemplifications are reviewed and future challenges and opportunities for the impregnation approach in SOFCs are explored.