Sulfate Resistance Research Articles

Direct synthesis of small-sized platinum nanoflowers loaded on carbon supports as highly efficient and stable uricase-like nanozyme

The development of multifunctional and high-performance nanozymes via a facile strategy is especially intriguing for biomedical applications. Here, a surfactant-free simple method was used to successfully load small-sized Pt nanoflowers (PtNFs) onto reduced graphene oxide (rGO) based on single glucose. PtNF@rGO nanozyme (NM) exhibits highly excellent catalytic activity, and displays good stability and recyclability in degrading uric acid. More importantly, this robust integrated nanozyme shows strong sulfur resistance. The analysis of the structure-function relationship indicates that the small sized nanoflower structure and the interaction between PtNF and rGO in the integrated catalysts contribute to the catalytic activity and stability collectively. Interestingly, PtNF@rGO nanozymes can mimic the cascade processes of uricase/catalase to degrade both uric acid and H2O2. Furthermore, the inhibition effect of PtNF@rGO on the crystallization of urate crystals was investigated. PtNF@rGO nanozyme prolongs the nucleation induction time (from 10 to 72 h) during the crystallization of sodium urate significantly. This study reveals the significance of morphology regulation in constructing high-performance and multifunctional hybrid nanozymes, broadening the application of nanozyme in the biomedical field.

Sulfate resistance of UHPC during dry-wet cycling and energy dissipation under compression

To study the sulfate resistance of ultra-high performance concrete (UHPC) in saline soil area of western China, four kinds of sulfate solution concentrations (0 %, 5 %, 10 %, 15 %) and 18 dry-wet cycle tests for 540 days were carried out on UHPC specimens. The effects of sulfate dry-wet cycles on the evolution of UHPC strength and energy were studied, the characteristic stress points during uniaxial compression of UHPC under sulfate dry-wet cycle were determined, based on the evolution law of each energy (total energy U, dissipated energy Ud , elastic stress Ue) at the characteristic stress points, the energy storage index was established to measure the damage degree of UHPC. The results show that the energy evolution process and damage mechanism of UHPC samples under sulfate-wet and dry cycle erosion are closely related to macro and micro changes. With the development of sulfate dry-wet cycle, the dissipative energy Ud and elastic strain energy Ue of UHPC at the characteristic stress points increased first and then decreased. The development trend of elastic strain energy Ue and dissipative energy Ud is more severe with the increase of sulfate solution concentration. The ratio of elastic strain energy at damage stress to elastic strain energy at peak stress (Ueib/Uei) is taken as the energy storage index Kib to measure the damage degree of UHPC, under 10%Na2SO4 erosion, Kib can be increased by 21.41 % at the highest and decreased by 29.67 % at the lowest compared with the initial value. It shows that the damage process of UHPC is difficult and then easy, and this index can accurately reflect the external force required for the damage of UHPC under sulfate dry-wet cyclic erosion, and provide a reference for the safe and stable operation of UHPC in saline soil area.

Achieving High Dispersion of Pd in Small-Pore Zeolite SSZ-13: A High-Efficiency Low-Temperature NOx Adsorber.

Passive NO x adsorber (PNA) materials are primarily considered for reducing nitrogen oxide emissions during the low-temperature cold start of a motor vehicle. Pd/SSZ-13 has attracted considerable attention because of its outstanding hydrothermal stability and sulfur resistance. Optimizing the dispersion of precious metal Pd in Pd/SSZ-13 is crucial for enhancing PNA performance and nitrogen oxide adsorption capability. In this study, we prepared Pd/SSZ-13 using different methods and evaluated their influence on the NO x adsorption capability. The characterization results show that the dispersion of precious metal Pd in the Pd/SSZ-13 catalyst prepared by the quantitative ion-exchange method is as high as 92.13%, and the loading amount is as high as 98.93%. Pd predominantly exists as Pd2+, achieving near-total loading and further improving the catalyst's NO x adsorption capacity. This study offers innovative approaches and methods for applying Pd/SSZ-13 as a PNA material, serving as a reference for its further optimization and performance enhancement. Continued research into the preparation and adsorption performance of Pd/SSZ-13 materials could offer solutions to reduce motor vehicle nitrogen oxide emissions.

Ruthenium-modified catalyst Ru-CeO2 significantly enhances mercury removal from sulfur-containing coal flue gas

In this study, we innovatively synthesized Ru-CeO2 catalysts by doping ruthenium dioxide (RuO2) with cerium dioxide (CeO2), which significantly enhanced the removal efficiency of mercury (Hg0) from coal-fired flue gases and tolerance to high sulfur environments. We effectively responded to the complex challenges in coal-fired flue gases. Nitrogen adsorption-desorption, X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) were employed to characterize the catalyst. It was found that the mercury removal efficiency of the Ru-CeO2 catalyst was significantly higher than that of unmodified CeO2 at 125°C, demonstrating excellent mercury removal performance and sulfur resistance. In addition, in the field of mercury removal and sulfur resistance, the innovative combination of characterization technique and density functional theory (DFT) was used to deeply explore the adsorption behaviors of Hg0 and SO2 on the surface of the catalyst and their mechanisms, revealing the changes in surface charge distribution and the increase in active sites caused by ruthenium doping. The changes in the electronic structure of the active sites on the catalyst surface were revealed by DFT calculations, which provide a scientific basis for the optimization and screening of catalysts in the future and are of great significance to the field of coal-fired flue gas purification and catalyst science.

Resistance to magnesium sulphate attack of binary and ternary cementless self-compacting alkali-activated mortar

The aim of this study is to investigate the effect of sulphate on self-compacting alkali-activated mortars (SCAAMs) produced using volcanic scoria (V), boron waste (B) and granulated blast furnace slag (G) together with alkali activators. Thus, the production of cement-free alkali-active mortar by recycling waste and reducing the CO2 effect increases the importance of this study. The fact that the waste material is provided free of charge and that V is readily available from nature provides economic advantages in the production of these mortars. In this experimental study, magnesium sulphate solution was utilized to define the sulphate resistance of SCAAMs. In binary SCAAMs, B was used with G in a ratio of NS:NH = 3.0, with an increase from 5 % to 15 %; in ternary mixtures, B was used together with G and V in the same proportions, in a ratio of NS:NH = 1.0. The tests involved immersion in 5 % magnesium sulphate solution for 1, 3 and 6 months. Mass development, compressive strength, visual inspection and microstructural changes were investigated. In general, the binary SCAAMs performed better in magnesium sulphate solution than the ternary SCAAMs, except in the 6th month. Considering the samples with the highest B content, a 100 % loss of compressive strength occurred in the B15G85 sample under the influence of sulphate for 6 months, while a loss of compressive strength of about 15 % occurred in the B15G40V45 sample. The results showed that the increase in B content caused a severe deterioration of the sulphate effect in the samples over time and that the V additive had a positive effect on the sulphate resistance.

Insights into the Acidic Site in Manganese Oxide in Terms of the Sulfur and Water Tolerance of Low-Temperature NH3 Selective Catalytic Reduction.

A critical constraint impeding the utilization of Mn-based oxide catalysts in NH3 selective catalytic reduction (NH3-SCR) is their inadequate resistance to water and sulfur. This vulnerability primarily arises from the propensity of SO2 to bind to the acidic site in manganese oxide, resulting in the formation of metal sulfate and leading to the irreversible deactivation of the catalyst. Therefore, gaining a comprehensive understanding of the detrimental impact of SO2 on the acidic sites and elucidating the underlying mechanism of this toxicity are of paramount importance for the effective application of Mn-based catalysts in NH3-SCR. Herein, we strategically modulate the acidity of the manganese oxide catalyst surface through the incorporation of Ce and Nb. Comprehensive analyses, including thermogravimetry, NH3 temperature-programmed desorption, in situ diffused reflectance infrared Fourier transform spectroscopy, and density functional theory calculations, reveal that SO2 exhibits a propensity for adsorption at strongly acidic sites. This mechanistic understanding underscores the pivotal role of surface acidity in governing the sulfur resistance of manganese oxide.

New insights and reaction mechanisms in the design of catalysts for the synergistic removal of NOx and VOCs from coke oven flue gas: Dual regulation of oxidative properties and acidic sites

The acid and redox sites of the MnCo catalysts are simultaneously fine-tuned by the addition of V. A dual-function catalyst, designated as V0.5Mn5Co5, has been constructed for the synergistic removal of NOx and volatile organic compounds under coke-oven flue gas conditions, which exhibits > 95 % NOx conversion and > 80 % N2 selectivity at 180–300 °C. Meanwhile, it removes 70 % of ethylene at 240 °C. Besides it has excellent sulfur and water resistance. The characterization results indicate that this acid-redox dual sites modulation strategy appropriately weakens the oxidation capacity of the catalysts while increasing the surface acidity of the catalysts. The catalyst mainly performs SCR reaction through the E-R mechanism, and N2O is generated through the transition dehydrogenation of NH3 and NSCR reaction. Ethylene is first adsorbed on the catalyst surface then oxidized to form carbonate species, and finally decomposed to CO2. Ethylene oxidation follows the MvK mechanism. There is a competitive adsorption between NH3 and C2H4, and a mutual inhibition between the SCR reaction and the ethylene oxidation reaction. V0.5Mn5Co5 exhibits excellent synergistic removal of NOx and VOCs in coke oven flue gas compared with commercial VWTi catalysts, which indicates great promise for industrial application.

Proportioning Study for Low-carbon Sulfate-resistant Concrete by Microbial Corrosion Testing

In addition to water absorption and chloride permeability measurement, sulfate resistance testing by microbial corrosion was conducted on low-W/B concretes made using large amounts of supplementary cementitious materials, including GGBF slag, for use as sewage pipes. The corrosion testing was conducted in a corrosion chamber at 30°C with a H2S concentration of 100 ppm, in which specimens were exposed to the environment under two conditions: one group in the gas and the other partially submerged in circulating sewage water. After exposure for one year, the corrosion rate in the partially submerged phase tended to be 1.3 to 2.9 times higher than in the gas phase. Also, the amount of corrosion was compared, with the corrosion products being examined by EPMA. Exposure to the gas phase and partially submerged phase was thus found to represent the stage of forming monosulfates and dihydrate gypsum and ettringite, respectively. Deterioration was found to proceed at a higher rate as the pH value on the concrete surfaces decreased. Within the range of this study, the addition of silica fume and small-size GGBF slag led to no appreciable effect.

Influence of recycled rubber and glass aggregates on magnesium sulfate resistance of geopolymers: Physio-mechanical properties and mechanisms

Recycled rubber aggregates (RRA) and recycled glass aggregates (RGA) are sustainable alternatives to natural aggregates. However, the influences of RRA and RGA on the magnesium sulfate resistance of geopolymers remain unclear. Previous studies have focused on the influences of binder type and composition on magnesium sulfate resistance but have neglected the role of aggregates. This study bridges this gap and demonstrates the influences of RRA and RGA on the magnesium sulfate resistance of geopolymers. This study investigated the physical properties, mechanical properties and phases of FA and GBFS-based geopolymers containing 0:10 – 10:0 RRA and RGA after being exposed to 5 % MgSO4 solution for 90 days. The results showed that compared to 100 % RGA, the 90-day length and mass of 100 % RRA increased by 50.48 and 33.22 times, respectively, and the 90-day compressive, flexural and splitting tensile strengths of 100 % RRA decreased by 65 %, 43.28 % and 56.75 %, respectively. However, the changes in length and mass of 100 % RGA were very small, and the mechanical properties even slightly increased rather than decreased. RRA + RGA showed an interval performance between 100 % RRA and 100 % RGA. The different magnesium sulfate resistance of RRA and RGA were attributed to the following mechanisms. RRA caused much higher drying shrinkage of geopolymers than RGA because the soft nature of RRA increased uncoordinated deformation, leading to micro-cracks in the matrix before magnesium sulfate exposure. The pre-existing micro-cracks served as physical transportation paths for external ions to diffuse into the interior of specimens, leading to expansive gypsum crystals formed in these micro-cracks. The accumulation of expansive gypsum crystals enlarged these micro-cracks and facilitated their propagation, leading to the expansion, cracking and degraded mechanical properties. By contrast, RGA reduced drying shrinkage due to its hard nature, which limited the availability of micro-cracks as physical transportation paths for external ions and therefore reduced the formation of expansive gypsum crystals and improved the magnesium sulfate resistance of geopolymers.

Enhancement in the Hg0 oxidation efficiency and sulfur resistance of CuCl2-modified MnOx-CeOx nanorod catalysts

Enhancement in the Hg0 oxidation efficiency and sulfur resistance of CuCl2-modified MnOx-CeOx nanorod catalysts

Unveiling the promotional performance of CO oxidation over Na-doped Pt-0.5P&W/TiO2 catalyst: “SMSI” effect of Na in catalysis

The dopant WO3 of the catalyst Pt-0.5P&W/TiO2 enhanced the SO2 resistance of the catalyst for CO oxidation in sintering waste gas, but it also had an impact on strong metal-support interactions (SMSI), which decreased the CO catalytic activity. Adding alkali metal Na to Pt-0.5P&W/TiO2 can effectively improve the CO catalytic performance. The Pt–O–Na bond replaced the Pt–O–Ti bond, allowing Na to act as an electron and structure promoter instead of TiO2 to contribute the electronic and synergistic effects in catalysis. XPS and EPR date indicated that the positively charged group centered on Pt adsorbed hydroxyl groups by electrostatic interaction, which co-acted with Na to form Pt-Ox(OH)yNa. In situ infrared data indicated that Na promoted the electron density on the Pt surface leading to the disproportionation of CO on the Pt surface to produce inactive C*. The production of C* facilitated the adsorption and activation of O2 by blocking the single-layer adsorption of CO on Pt. The active oxygen species adsorbed on the catalyst surface increased the CO activity of the catalyst. In sulfur-containing flue gas conditions, SO2 reacted with Na around Pt to generate sodium sulfate, which enhanced the local acidity of the active site and the sulfur resistance of the catalyst.

Analysis of mercury removal and sulfur resistance of CrOx-MnOx-SnOx-TiO2 catalysts

To investigate the ability of CrOx-MnOx-SnOx-TiO2 composite catalysts to adsorb and remove substances, particularly in the presence or absence of SO2, Sn was included in CrMnTi catalysts throughout the production procedure. The incorporation of Sn was found to boost the specific surface area, optimize the pore structure, and augment the number of active sites, as determined using characterization methods such as XRD, XPS, and BET. When Sn metal oxides were included in MnTi catalysts individually, the resulting MnSnTi catalysts showed a limited capacity to remove Hg0. However, adding Sn metal oxides allowed for widening the temperature range in which the catalysts found successful application. This will increase the range of application temperature and is of very successful importance for large-scale commercial applications. They demonstrate that, by incorporating chromium metal oxides, the oxygen Oβ reactivity within the MnSnTi catalyst increases, resulting in a greatly improved capacity for Hg0 removal and its resistance to sulfur. This study details the combined effect of Cr, Mn, and Sn ternary composite oxides on sulfur resistance and mercury removal. The result shows that Sn promotes the strengthening of both the physical properties of the catalyst and the adsorption of mercury while also assisting in the dispersion of the catalyst. Cr enhances the ability of the catalyst to transfer electrons while in oxidation and, at the same time, favours the remaining high valence of Mn. Mn supports the catalyst for oxidizing mercury by changing its multivalent state. The CrMnSnTi catalysts have exceptional efficacy in removing mercury and possess excellent resistance to sulfur, making them an ideal catalytic option for industrial demercury removal. The catalysts exhibited excellent efficacy in removing mercury and showed strong sulfur resistance.

Reversal of gentamicin sulfate resistance in avian pathogenic Escherichia coli by matrine combined with berberine hydrochloride.

In recent years, the evolution of antibiotic resistance has led to the inefficacy of several antibiotics, and the reverse of resistance was a novel method to solve this problem. We previously demonstrated that matrine (Mat) and berberine hydrochloride (Ber) had a synergistic effect against multidrug-resistant Escherichia coli (MDREC). This study aimed to demonstrate the effect of Mat combined with Ber in reversing the resistance of MDREC. The MDREC was sequenced passaged in the presence of Mat, Ber, and a combination of Mat and Ber, which did not affect its growth. The reverse rate was up to 39.67% after MDREC exposed to Mat + Ber for 15 days. The strain that reversed resistance was named drug resistance reversed E. coli (DRREC) and its resistance to ampicillin, streptomycin, gentamicin, and tetracycline was reversed. The MIC of Gentamicin Sulfate (GS) against DRREC decreased 128-fold to 0.63µg/mL, and it was stable within 20 generations. Furthermore, the susceptible phenotype of DRREC remained stable within 20 generations, as well. The LD50 of DRREC for chickens was 8.69 × 109 CFU/mL. qRT-PCR assays revealed that the transcript levels of antibiotic-resistant genes and virulence genes in the DRREC strain were significantly lower than that in the MDREC strain (P < 0.05). In addition, GS decreased the death, decreased the bacterial loading in organs, alleviated the injury of the spleen and liver, and decreased the cytokine levels in the chickens infected by the DRREC strain. In contrast, the therapeutic effect of GS in chickens infected with MDREC was not as evident. These findings suggest that the combination of Mat and Ber has potential for reversing resistance to MDREC.

Formation of Fe2(SO4)3-Fe2O3 interface induced by OCFGs electrostatic anchoring on AC surface: High efficiency NH3-SCR performance at low temperatures

Low-temperature activity and SO2 poisoning were the key factors limiting the application of NH3-SCR catalysts. In this study, Fe2(SO4)3/AC and Fe2(SO4)3/OAC catalysts were prepared by oxidation function modification and incipient wetness impregnation. In the temperature range of 100–250 ℃, the catalytic performance and SO2 resistance of Fe2(SO4)3/AC and Fe2(SO4)3/OAC catalysts were investigated, the denitrification efficiency increased from 28 % (Fe2(SO4)3/AC) to 80 % at 100 °C and reached 100 % at 170 °C, and 100 ppm SO2 was introduced at 250 ℃ for 24 h, the denitrification efficiency remains 100 % unchanged. The mechanism of activity enhancement was further explored by BET, XRD, ICP, TG, XPS, FT-IR, H2-TPR and NH3-TPD. The results showed that (NH4)2S2O8 modification enhanced the surface acidity, and the increase of surface oxygen-containing functional groups improved the redox performance. At the same time, due to electrostatic anchoring effects of oxygen-containing functional groups, Fe3+ and SO42- were adsorbed at different sites and promoted the binding of S to the carbon skeleton to form −C-S-C-. Thus, the interaction between OAC and Fe2(SO4)3 caused part of Fe2(SO4)3 to decompose into Fe2O3, and the formation of Fe2(SO4)3-Fe2O3 interface further enhanced the acidity and redox properties. More importantly, the decomposition temperature of NH4HSO4 was lower and the decomposition was more thorough on the Fe2(SO4)3/OAC than that of Fe2(SO4)3/AC. Finally, the possible mechanism of (NH4)2S2O8-modified Fe2(SO4)3/OAC catalyst to improve NH3-SCR performance was proposed, which is of great significance for the development of NH3-SCR catalyst with sulfur resistance at low temperatures.

Facile one-pot synthesis of Cu-SSZ-39 catalysts with excellent catalytic performance in NH3-SCR reaction

Nitrogen oxide (NOx) emission from diesel vehicles has caused severe pollution to the atmospheric environment. Selective catalytic reduction of NOx with NH3 (NH3-SCR) technology has been widely used to remove NOx from diesel vehicle exhaust. Cu-SSZ-39 zeolites have exhibited excellent NH3-SCR catalytic activity and hydrothermal stability, giving them promise for practical application. A facile one-pot synthesis method to prepare Cu-SSZ-39 zeolites was developed, with complete crystallization achieved in 24 h. Moreover, the Cu content could be controlled by adjusting the amount of Cu-TEPA added without the need for complex post-treatment processes. Cu-SSZ-39 catalysts synthesized through the one-pot synthesis method exhibited excellent NH3-SCR activity and hydrothermal stability. The one-pot-synthesized Cu-SSZ-39 catalysts contained in situ generated CuO species, which can act as sacrificial sites to protect Cu2+ under sulfidation conditions. Considering their efficient synthesis process, excellent NH3-SCR activity, hydrothermal stability and sulfur resistance, one-pot-synthesized Cu-SSZ-39 catalysts hold great promise for future applications.

Fatigue Evaluation of Sulphate-Attacked Industrial Waste-Based Concrete Using Concrete Damaged Plasticity Model

AbstractSulphate attack is a major cause of concrete deterioration in marine environments and its interaction with wave-induced cyclic loading exacerbates the damage. This study has evaluated strengths and fatigue performance (i.e. fatigue life, strain and residual displacement) of sulphate-attacked concrete containing silicomanganese slag, fly ash (FA) and silica fume (SF). Compressive strength, tensile strength and sulphate profile of sulphate-attacked concrete were measured experimentally. Sulphate-induced damage constitutive relations were formulated and used with concrete damaged plasticity (CDP) model to simulate fatigue loading. Experiment showed that incorporating silicomanganese slag lowered sulphate resistance by 4.8–6.6% due to increased sulphate intrusion, but synergy with FA and SF enhanced the resistance by 7.3–13.8% at 365 days. The sulphate penetration depth was 0–20 mm, and the intruded sulphate increased exponentially over time. To evaluate fatigue loading in CDP model, the non-uniform damage was determined as correlation between strength degradation and integral area of sulphate profile. Numerical results were in good agreement with experimental data from literature, with differences of 5.8–26.2% in fatigue life, 9.1–30.1% in fatigue strain and 18.1–41.9% in residual displacement. In long-term deterioration, numerical analysis found that increasing sulphate concentration significantly shortened fatigue life. Despite silicomanganese slag lowered concrete sulphate and fatigue resistance, the inclusion of FA and SF improved the durability and sustainability of concrete for potential marine applications.

Influence of Surface Basic Sites and Oxygen Vacancies on the Performance of Metal-Modified Rod-Like Ceria Catalysts for Low-Temperature Hydrolysis of Carbonyl Sulfide.

This study utilized a hydrothermal method to synthesize various metal-modified rod-like ceria catalysts (Fe, Co, Cu, Ni, La), achieving efficient COS removal at low temperatures. The research identified surface oxygen vacancies and basic sites as critical factors that influence the catalytic performance of COS hydrolysis. The addition of different metals to pristine ceria rods increased the specific surface area, oxygen vacancy content (Ov), and basicity, which enhanced the catalysts' sulfur resistance and stability. Among all the catalysts tested, 10La-CeO2 demonstrated the highest COS removal rate. This is because La doping significantly augmented Ov, providing more H2O adsorption and activation sites. Furthermore, 10La-CeO2 showed enhanced Lewis basicity, making it easier for COS to adsorb and promote hydrolysis. The in situ DRIFTS results confirmed that appropriate oxygen vacancies and basic sites favored the formation of intermediates such as HCO3 - and HSCO2 -, promoting the decomposition of COS into H2S and CO2.

ПЕРСПЕКТИВЫ ИСПОЛЬЗОВАНИЯ ОТХОДОВ СТРОИТЕЛЬНОЙ КЕРАМИКИ ПРИ ПРОИЗВОДСТВЕ СТРОИТЕЛЬНЫХ МАТЕРИАЛОВ

The main technological aspects of the production of building ceramics are given. Based on the analysis of literary sources, a comprehensive assessment of the feasibility of using construction ceramic waste as a secondary raw material for the production of new building materials was carried out. Based on the research of modern scientists, it has been established that the waste from the scrap of building ceramics is suitable for use as an aggregate, partial replacement of cement and a reactive additive in concretes and mortars. When using scrap of con-struction ceramics as an aggregate, it is recommended to limit the substitution of natural aggregate at the level of 20-30%, together using various additives: plasticizing and improving rheotechnological and physico-mechanical properties of concrete. Finely ground waste from brick scrap has pozzolan activity and, when used as a reactive additive or partial replacement of cement in concretes and mortars, up to 20-25% can improve the structure of cement stone, increase strength, reduce macroporosity and penetration of chloride ions, and increase sul-fate resistance. This kind of binder is prone to a later set of strength compared to Portland cement. In addition, the waste of building ceramics can be used in the production of alkali-activated cements and slag-alkali binders, as well as s raw materials for the production of new bricks or the construction of road surface bases. It has been revealed that the production of building materials and products based on con-struction ceramics waste is a promising direction for the development of construction production. It is possible not only to obtain materials of equal quality to products based on natural raw materials, but also with improved characteristics.

Crystalline phase-modulated PtOx nanoparticles exhibit superior methane combustion performance and sulfur poisoning resistance: Multi-interaction regulation

Up to now, methane combustion catalysts generally suffer from issues such as poor reaction stability and susceptibility to sulfur poisoning, which have become the key factors restricting their application, so it is necessary to construct catalysts with excellent chemical stability of the active center and strong sulfur resistance. Here, we showed the crystal phase-modulated state of PtOx nanoparticles (PtOx NPs) on TiO2 and investigated their effects on the reactivity of methane catalytic combustion and anti-SO2 poisoning properties. It was found that Pt/r-TiO2 showed superior activity, stability, and resistance to SO2 poisoning. Transmission electron microscope (TEM) images showed that the PtOx NPs on the surface of r-TiO2 were much more stable than a-TiO2 for the reason that the Ostwald ripening of PtOx NPs on a-TiO2 was facilitated due to the strong metal-support interaction (MSI) between PtOx NPs and TiO2 and the low migration energy of the PtOx NPs on TiO2, while they were moderate of Pt/r-TiO2, and then the active sites were stabilized during methane combustion. The activity was controlled by the size and electronic structure of PtOx NPs, which were stable on the surface of r-TiO2 with a higher Pt4+ content, and the density functional theory (DFT) calculations further revealed the role of r-TiO2 in increasing the quantities of surface oxygen vacancies. Moreover, the SO2 tolerance of Pt/r-TiO2 was also the best among all kinds of Pt-based catalysts prepared, which was attributed to the minimal adsorption energy (Ead) of SO2 on r-TiO2, and the absence of sulfate and sulfite deposition on the Pt/r-TiO2 catalyst confirmed by TGA and in-situ DRIFTS studies on SO2 adsorption. In this research, the anti-SO2 poisoning and reaction stability were realized by adjusting the interaction between SO2, active components, and supports, which provided a new insight for the design of stable Pt-based SO2-resistant catalysts.

A comprehensive literature mining and machine learning to decipher and predict effects of concrete materials on concrete corrosion of sewer pipe

ABSTRACT The concrete composition of different pipelines varies greatly, and a comprehensive analysis of the impact of concrete design on pipeline corrosion is required. Developed an integrated model based on Scikit-Optimize, XGBoost and SHAP to analyze concrete’s carbonation and sulfuric acid resistance from five aspects: binder type, supplementary cementitious material (SCM’s), aggregate, admixture and w/b. Choose Scikit-Optimize for parameter optimization. As an explanation model, the SHAP model can perform analysis well and explain the analysis basis of the XGBoost training model. The established model can accurately predict the corrosion effect (R2 >0.987) without overfitting. Binder should be maintained at 380 to 400 (kg/m3). Water/binder and coarse aggregate/binder are the two main factors that influence the binder, and they should be maintained at a ratio of around 0.4 to 0.6 and 2.5, respectively. Fly ash (FA) should be SCM’s used as at a range of 300 to 350 (kg/m3) to improve corrosion resistance.