Effect Of Alkaline Earth Metals Research Articles

Blue-excitable orange-red-emitting M3Y(PO4)3:Pr3+ (M = Ba, Sr, Ca) phosphors for multifunctional applications

Research on multifunctional luminescent materials has become an emerging trend for new applications of optical sensing, monitoring, anticounterfeiting, lighting, etc. Herein, a library of Pr3+-doped M3Y(PO4)3 (M = Ba, Sr, Ca) phosphors was prepared for careful spectroscopic studies in potential lighting and optical temperature sensing applications. With the help of density functional theory calculation, diffuse reflectance spectra, and steady/dynamic photoluminescence spectra, the effects of alkaline earth metals on the fluorescence properties of M3Y(PO4)3:Pr3+ were studied systematically. Under the excitation of blue ∼ 445 nm, orangish-red fluorescence of approximately 602 nm was efficiently detected due to Pr3+ 1D2 → 3H4 transition, which becomes stronger by regulating alkaline-earth elements from Ba to Sr and to Ca. An optimized Ca3Y(PO4)3:0.7%Pr3+ sample was validated with excellent thermal stability 89%@423 K and further applied to fabricate a white light emitting diode by combining with commercial YAG:Ce3+ phosphors on a 445 nm blue chip. Specifically, CIE chromaticity coordinates (0.3510, 0.3650) and correlated color temperature (∼ 4838 K) were obtained for an obvious improvement. Moreover, optical thermometry properties of Ca3Y(PO4)3:0.7%Pr3+ were explored on basis of Pr3+ 3P0-3P1 thermally coupled energy levels. Their fluorescence intensity ratios following the Boltzmann equation could be operated over 298-598 K with superior relative sensitivity ∼ 0.87% K-1 at 298 K. These interesting results for multifunctional luminescence will greatly promote the development of novel Pr3+-doped luminescent materials as well as the related photoelectric devices.

Reducing the poisoning effect of adsorbed alkaline earth metal on Nb active sites with sulfates for NH3-SCR

Reducing the poisoning effect of alkaline earth metals over catalysts in industrial fields presents a great challenge to selective catalytic reduction (SCR) of NOx with ammonia. Herein, we successfully introduce sulfates to the surface of supported manganese-based oxides (Nb/MnO2-S) for trapping calcium species, and Nb/MnO2-S catalyst with superior low-temperature performance and calcium-resistant property still exhibits excellent de-NOx activity in a wide operating temperature window (175–350 °C, over 80 % NOx conversion with a gas hourly space velocity of 60,000 h−1) after calcium poisoning. In this case, the addition of sulfates increased the quantity of chemisorbed oxygen on Nb/MnO2-S, thus accelerating the redox cycle in NH3-SCR reaction. Significantly, compared with calcium-poisoned Nb/MnO2, relevant spectroscopy analysis and theoretical calculations further reveal that sulfates species prefer to interact with calcium and release the Nb active sites, which maintains the efficient NH3 adsorption and preserves a large amount of Brønsted acid sites over calcium-poisoned Nb/MnO2-S, thus promoting calcium-resistant performance. This work will provide a general strategy to develop calcium-resistant SCR catalysts with low-temperature activity for industrial applications.

Effect of alkaline-earth metals (Mg, Ca, Sr, and Ba) on precipitated iron-based catalysts for high-temperature Fischer-Tropsch synthesis of light olefins

For the high-temperature Fischer-Tropsch synthesis (HTFT) of light olefins (C2=-C4=), alkaline-earth metals (Mg, Ca, Sr, and Ba) modified FeMn catalysts were prepared using precipitation and impregnation methods. It was demonstrated that the electron-giving interaction of Ca, Sr, and Ba decreased the adsorption of H species while improving the dissociative adsorption of CO. This interaction resulted in the production of χ-Fe5C2, which increased CO conversion and C2=-C4= selectivity. Compared with Ca and Ba, the FeMnSr catalyst had the strongest CO dissociative adsorption capacity and the highest χ-Fe5C2 content with the best FTS performance. When Sr and Na were introduced simultaneously, the synergistic effect of Sr and Na inhibited the formation of θ-Fe3C and the aggregation of catalyst particles, and also increased the χ-Fe5C2 content. This synergistic effect resulted in the highest surface basicity of FeMnSrNa catalyst, the highest electron cloud density on the surface of Fe atoms, the weakest H species adsorption, the strongest CO dissociative adsorption, and the highest total amount of active iron carbide, which improved the FTS performance. The light olefins yield of FeMnSrNa catalyst (427.0 g/(h·kgCat)) was significantly higher than that of FeMnSr catalyst (341.4 g/(h·kgCat)) and FeMnNa catalyst (80.6 g/(h·kgCat)).

Chemical looping with oxygen uncoupling of biomass-derived hydrochar with Cu-based oxygen carriers modified by alkaline earth metals

In this paper, the effect of alkaline-earth metals (AEMs, Ca, Ba, and Sr) on the performance of CuO/ZrO2 oxygen carriers (OCs) and the hemical looping with oxygen uncoupling (CLOU) process of wheat-derived hydrochars with these Cu-based OCs were investigated. The results showed that after multiple cycles, the crystal phases of modified Cu-based OCs were the same as that of pure CuO/ZrO2 OC without any interaction between them. Due to the catalytic effects of AEMs, an increase in the decomposition of wheat and hydrochar-235 in modified Cu-based was observed at 500 °C. The combination of Ca and HTC promotes reoxidation, while Ba and Sr inhibit reoxidation. Notably, the Cu-based OCs exhibited moderate agglomeration after 20 redox cycles at 950 °C. The results of the kinetic analysis indicate that the chemical order models and diffusion models can suitably describe the first combustion stage for wheat and hydrochars with Cu-based OCs, respectively. The geometrical contraction model was also found to most suitably describe the second combustion stage of all samples. These results suggest that a combination of hydrothermal carbonization pretreatment with AEMs modification is an efficient approach for CLOU using CuO-based OCs.

La0.7(Ca, Sr)0.3Ni0.6Mn0.5O3 perovskites for photothermal catalytic reforming of toluene: The role of oxygen species in the photothermal synergistic effect

Photothermal steam reforming (PTR) has emerged as an attractive approach for catalytic tar removal, due to the excitation of the photothermal synergistic effect. However, the role of oxygen species in PTR is still unclear. In this paper, the effect of alkaline earth metals (Ca and Sr) A-site-substitution on perovskite LaNi0.6Mn0.5O3 was investigated to reveal the role of oxygen species in PTR. The substitution of alkaline earth metals into perovskite lattice affected the dispersion of nickel and significantly adjusted the active oxygen species content on the catalyst surface. Oxygen species are crucial to the carbon deposition behavior of catalysts in PTR. La0.7Ca0.3Ni0.6Mn0.5O3 was rich in reactive oxygen species, which effectively inhibited the deposition and graphitization of coke, resulting in its good coke resistance and catalytic stability in PTR. Ultraviolet–visible light (UV–vis) supported the formation of oxygen vacancies and the dissociation of H2O to hydroxyl radicals through the photochemical reaction, which ultimately increased the surface adsorbed oxygen contents. Meanwhile, UV–vis promoted the migration and reaction of lattice oxygen. The photoactivation of oxygen species by UV–vis effectively enriched active oxygen species and improved the coke resistance, which resulted in enhanced catalytic stability of PTR at low-temperature.

Insights into the promotional effect of alkaline earth metals in Pt-based three-way catalysts for NO reduction

Enhancing NO reduction efficiency of Pt-based three-way catalysts (TWCs) is very challenging due to poor NO activation ability. In this work, NO reduction performance was improved by introducing alkaline earth metals to adjust the electron environment of Pt, while the promoting effect was systematically studied. Structure-activity relationship indicated that NO reduction activity over the Pt-M/LA catalysts (M = Mg, Ca, Sr or Ba, LA = La-Al2O3) increases as the electronegativity of M decreases, and the TOF of Pt-Ba/LA is about 3 times more active than that of Pt/LA, which is attributed to more Pt0 species resulting from Pt-Ba interaction. Moreover, kinetic studies revealed that alkaline earth metals weaken the poisoning effect of CO and improve promoting effect of HCs, leading to an improved NO adsorption and an increased reaction rate of NO with CO and HCs. This study provides an insightful understanding for the promotional effect of alkaline earth metals on NO reduction over Pt-based TWCs.

Influence of Nitrate Species A(NO<sub>3</sub>)<sub>2</sub> on Physico-Mechanical Properties of the Aluminosilicate Adhesives for Wooden Structure

The article presents the results of studies of the positive effect of compounds of the type A(NO3)2, as modifiers of the aluminosilicate adhesive of the composition Na2O∙Al2O∙6SiO2∙20H2O, on increasing the strength of adhesive joints of wood of various species. The grade strength increases 1.39 times compared to the strength of the adhesive that does not contain these compounds. According to the degree of influence on the shear strength along the fibers, the additives can be ranked in the series Ba (NO3)2 > Ca (NO3)2 > Mg (NO3)2 > 95%Ca (NO3)2+5%NH4NO3. It is noted that for gluing samples from a pine substrate, it is advisable to add magnesium and barium nitrates to the aluminosilicate glue in an amount of 1% (by weight); beech wood - calcium and barium nitrates in the amount of 1 and 0.5% (by weight); oak wood - calcium nitrates in an amount of 1% (by mass), a mixture of nitrates in an amount of 0.5% (by mass) and barium nitrate in an amount of 0.5 and 1.5% (by mass). According to the influence on the strength of adhesive joints, the substrates can be ranked in the order beech > oak > pine. Further studies will present the results of the effect of alkaline earth metal nitrates on the deformation properties of adhesive joints and on rheokinetic and colloid-chemical properties.

Effect of Alkaline Earth Metals Doping on the Electronic Structure, Magnetic and Optical Properties of g-SiC Monolayer System by First Principles Calculation

The band structure, electronic, magnetic, and optical properties of g-SiC monolayers doped with alkaline earth metals (Be, Mg, Ca, Sr, and Ba) are calculated by means of first principles based on density functional theory. Although the intrinsic g-SiC monolayer is nonmagnetic, it shows magnetic properties after doping with alkaline earth metals. The magnetic moments are, in the order of the above-named dopants, 1.583 μ B, 1817 μ B, 2.000 μ B, 2.000 μ B, and 2.000 μ B. Charge transfer and the net spin charge occur mainly between the dopant atom and surrounding C atoms. The results show that the conductivity of g-SiC can be greatly improved by doping with alkaline earth metals, a technique that can be applied to the field of semiconductor spintronics. High absorption peaks in the ultraviolet indicate that the material has potential applications in UV optoelectronic devices.

Alkaline-Earth Metal Effects on Physical Properties of Ferromagnetic AVO3 (A = Ba, Sr, Ca, and Mg): Density Functional Theory Insights.

The effects of alkaline-earth metals on electronic, optical, thermodynamic, and physical properties of ferromagnetic AVO3 (A = Ba, Sr, Ca, and Mg) have been investigated by first-principles calculations within the GGA+U formalism based on density functional theory. The optimized structural parameters are in good agreement with the available experimental results that evaluate the reliability of our calculations. The cell and mechanical stability is discussed using the formation energy and Born stability criteria, respectively. The mechanical behaviors of AVO3 are discussed on the basis of the results of elastic constants, elastic moduli, Peierls stress, and Vickers hardness. The nature of the ductile–brittle transition of AVO3 compounds was confirmed by the values of Pugh’s ratio, Poisson’s ratio, and Cauchy pressure. The electronic band structures, as well as density of states, reveal the half-metallic behavior of BaVO3 and SrVO3. However, CaVO3 and MgVO3 exhibit spin-gapless and magnetic semiconductor characteristics, respectively. The microscopic origin of the transition from the half-metallic to semiconductor nature of AVO3 is rationalized using electronic properties. The presence of covalent, ionic, and metallic bonds in AVO3 compounds is found by the analysis of bonding properties. The single-band nature of half-metallic AVO3 is seen by observing hole-like Fermi surfaces in this study. Furthermore, the various thermodynamic and optical properties are calculated and analyzed. The refractive index suggests that AVO3 could be a potential candidate for applications to high-density optical data storage devices.

Influence of alkali and alkaline earth metals on the hydrothermal liquefaction of lignocellulosic model compounds

The alkali and alkaline earth metals (AAEMs) in biomass have a certain influence on its thermochemical conversion process. In order to study the influence of water-soluble AAEMs on hydrothermal liquefaction (HTL) to produce bio-oil, the metal chlorides of K, Na, Ca and Mg were used as additives, and glucose, xylan and lignin were typical lignocellulosic biomass to conduct HTL experiments. The results showed that AAEMs increased the yield of bio-oil from glucose and xylan by 42.1% and 23.8%, respectively, and the catalytic effect of alkaline earth metals was stronger. However, the addition of mixed metal chloride reduced the bio-oil yield and energy recovery of lignin. AAEMs provided more H+ and OH− active radicals in the aqueous phase, which intensified the esterification reaction and decarbonylation reaction, and promoted the diversification of substances. Meanwhile, AAEMs improved the Higher heating value and energy recovery rate of bio-oil, and Mg promoted the reduction reaction, the calorific value of bio-oil was increased by 7.4, 1.5 and 2.5%, respectively.

Effects of alkaline-earth metals on CoMn-based catalysts for the Fischer–Tropsch synthesis to olefins

Alkaline-earth metal promoted CoMn catalysts with higher surface basicity benefit the carburization of CoMn oxides to form more Co2C nanoprisms for olefin formation, especially for long-chain olefins.

Simultaneous impregnation of Ni and an additive via one-step melt-infiltration: Effect of alkaline-earth metal (Ca, Mg, Sr, and Ba) addition on Ni/γ-Al2O3 for CO2 methanation

As part of carbon energy recycling, the CO2 methanation process in the power to gas technology, which converts the electricity grid into a gas grid [CO2 + 4H2 (produced by surplus electricity) → CH4] using a catalytic process, has been developed in the countries such as Germany and Denmark. To achieve an efficient catalytic process, the design of low-cost and high-efficiency catalysts is required. In this study, highly loaded Ni/Al2O3 catalysts (30 wt%) were prepared using the alkaline-earth metals (Mg, Ca, Sr, and Ba) via one-step melt-infiltration (OSMI) method. The Ni active sites were investigated, and the effectiveness of each alkaline-earth metal (Ca, Mg, Sr, and Ba) was determined. The catalytic activity was investigated in the temperature range of 275–400 °C and weight gas hourly velocity (WHSV) of 160,000 mL·gcat−1·h−1 under atmospheric pressure. Ni and alkaline-earth metals were uniformly dispersed into the pore structure of the alumina support. The average metallic Ni particle size of each catalyst was similar (~11 nm), and no severe Ni sintering was observed even at a Ni loading of 30 wt%. Mg-promoted Ni/Al2O3 catalyst was unsuitable for the OSMI method because the reduction of the Ni active sites was not completely accomplished at 400 °C. Ca-promoted Ni/Al2O3 catalyst afforded the best catalytic activity among other metal-promoted Ni/Al2O3 catalysts. Ca increased the CO2 adsorption amount and reducibility of the Ni active sites, and the optimum Ca loading was 5 wt%. However, the over-loading of Ca (10 wt%) was harmful to the catalytic activity of the Ni active sites.

Effect of alkaline earth metals on luminescence characteristic in Eu-Doped oxynitride phosphate glasses

In this article, a series of Eu-doped oxynitride phosphate glass samples are prepared. It is shown that the photoluminescence of Eu can be tuned through different alkaline earth metal ions (M2+). The luminous intensity of Eu2+ decreases with increasing ionic radius in the order of Mg＜Ca＜Sr＜Ba. And with the increased mismatch degree of radius between M2+ and Eu ions, the luminescence of Eu3+ gains intensity. The effects of M2+ on structure and luminescence characteristics of glass are mainly due to the following three factors: the field strength of M2+, the degree of mismatch between M2+ and Eu ions, and the influence of alkaline earth metals on the coordination tendency of N3− and O2− with Eu ions. The reduction mechanism is explained by combining the unequal substitution of Eu3+ ions for divalent alkaline earth metal cations with the reduction of Eu3+ by O2− and N3− ions. Our work provides a new perspective for studying the luminescence characteristics and mechanism of Eu ions in oxynitride Phosphate Glasses.

Effect of alkaline earth metals on the heat capacity and change of thermodynamic function of AK1M2 alloy on the basis of specific aluminum

It is known that high purity aluminum with a minimum content of impurities is widely used in electronic technology for the manufacture of conductive paths in integrated circuits. Hence the development of new compositions of alloys based on such a metal is a very urgent task. One of the promising alloys based on such a metal is alloy AK1M2 (Al + 1 % Si + 2 % Cu). This alloy was accepted by us as a model alloy and subjected to modification by alkaline earth metals.Heat capacity is the most important characteristic of substances and by its variation with temperature one can determine the type of phase transformation, the Debye temperature, the energy of formation of vacancies, the coefficient of electronic heat capacity, and other properties. In the present work, the heat capacity of the AK1M2 alloy with alkaline earth metals was determined in the “cooling” mode from the known heat capacity of a reference sample from copper. For which, by processing the curves of the cooling rate of samples from the alloy AK1M2 with alkaline earth metals and the standard, polynomials were obtained which describe their cooling rates. Further, by experimentally found values of the cooling rates of the standard and samples from alloys, knowing their masses, the polynomials of the temperature dependence of the heat capacity of the alloys and the standard were established, which are described by a four-term equation. Using the integrals of the specific heat, the models of temperature dependence of the change in enthalpy, entropy and Gibbs energy were established.The dependences obtained show that with an increase in temperature, the heat capacity, enthalpy, and entropy of alloys increase, and the values of Gibbs energy decrease. At the same time, additives of alkaline earth metals do not significantly reduce the heat capacity, enthalpy and entropy of the original alloy AK1M2 and increase the value of Gibbs energy. During the transition from alloys with calcium with barium, the heat capacity of the alloys decreases, which correlates with the heat capacity of pure alkaline earth metals within the subgroup.

A collaborative approach to in-situ oxysulfides and oxynitrides fixation in flue gas and energy recycling: Co-combustion of spent bleaching earth and coal

Spent bleaching earth (SBE) with high pollutant-producing coefficient was generated from lubricating oil refining and aviation kerosene hydrogenation unit in the oil refinery, while the disposal processes were limited due to its hazardous properties in the city. A simple and efficient approach was developed to co-combust SBE and coal in the company inner power plant, and synergetic effect was observed in SO2 and NOx reduction in flue gas and energy recycling of waste oil. The full-cycle combustion process was investigated in details under different mixing ratio of the two substances from 0 to 1000 °C. According to the TG/DSC-MS results, it was found that the introduction of SBE could reduce the decomposition temperature of coal from 475-931 °C to 450–815 °C, since the dehydrogenation and decarboxylation effects of metallic oxides and the high contacting area with oxygen provided by the porous structures of SBE. The tubular electric heating furnace-FTIR results showed that the concentration of typical pollutants in flue gas decreased obviously at the coal/SBE mixing ratio 5:1, among them, the maximum SO2 emissions reduction reached 32%. The chemical adsorption effect of alkaline earth metals and transition metal oxides and oxidation-reduction reaction between NO+NO3− and SO32− were proved as the main fixation mechanisms. The regenerated porous structures in SBE provide new adsorption site after the volatilization of adsorbed oils, so as to further enhance the fixation capacity. Co-combustion process of SBE and coal offered a promising way for simultaneous in-situ gaseous pollutant control in flue gas and energy recycling from SBE.

Exploring the effects of divalent alkaline earth metals (Mg, Ca, Sr, Ba) doped Nd2Ce2O7 electrolyte for proton-conducting solid oxide fuel cells

In this study, alkaline earth metals (Mg, Ca, Sr, Ba) doped Nd2Ce2O7 powders are synthesized by the gel auto-combustion method. The effects of alkaline earth metals doped Nd2Ce2O7 on the phase structure, chemical stability, microstructure, and electrical properties are evaluated by the X-ray diffraction, scanning electron microscopy, Raman spectroscopy and electrochemical testing. All electrolytes reveal a cubic fluorite structure with an Fm-3m space group and remain excellent chemical stability at different atmospheres. The grain size and density of ceramics increase significantly, and a large number of oxygen vacancies are created after alkaline earth metals incorporated into Nd2Ce2O7. Generally, the total conductivity is associated with the number of oxygen vacancies and microstructure of ceramics. The electrolyte of Nd1.85Mg0.15Ce2O7-δ exhibits the highest electrical conductivity of 0.923 × 10−2 S cm−1 and 1.542 × 10−2 S cm−1 in dry air and wet 5% H2–Ar atmosphere at 700 °C, respectively. Additionally, with alkaline earth metals doped Nd2Ce2O7 as electrolytes, the proton-conducting single cells have a better open circuit voltage and peak power density. The single cell based on Nd1.85Mg0.15Ce2O7-δ electrolyte can reach 0.890 V and 483 mW cm−2 at 700 °C. This was observed to stay constant without extreme degradation after short-term testing.

Spectroscopic analysis of alkaline-earth metal (Mg, Ca, Sr and Ba) co-doped Gd2O3:Eu phosphors synthesized via co-precipitation route.

This paper reports the effect of alkaline earth metals (AEM=Mg2+, Ca2+, Sr2+, Ba2+) co-doping on the structural, morphological and luminescent properties of Gd2O3:Eu phosphors. The concentration of the Eu3+ ions was fixed 4mol% to avoid the chances of the concentration quenching. AEM co-doped Gd2O3:Eu XRD profile confirmed the synthesis of cubic-phase of all the co-doped samples. FESEM micrographs exhibited the rod like morphology of the synthesized phosphors. All the samples were irradiated under UV excitation and exhibited intense, sharp and narrow emission spectra corresponding to the characteristic transitions (5D0→7F1,2,3,4) transitions of Eu3+ ions. The photometric parameters such as CIE coordinates, CCT and color purity are calculated. In order to probe the further luminescent properties and influence of the of alkaline earth metals on the local environment of the Eu ions in the host lattice, spectral parameters are calculated from Judd Ofelt theory from emission spectra. The obtained results suggest that AEM can be effectively utilized to enhance the luminescence intensity even after concentration quenching. The as-synthesized phosphors can be used in various solid state lighting devices and bio-sensors.

Effects analysis on the gasification kinetic characteristics of food waste in supercritical water

The gasification kinetic characteristics of food waste (FW) gasification by supercritical water (SCW) were investigated by examining the SCW gasification (SCWG) of FW in a quartz tube reactor, and the experimental results were investigated by using a series of kinetic models. The experimental results show that the carbon gasification efficiency increases with reaction temperature at the same residence time, and reactivity increases sharply at the early stage of gasification and then decreases with reaction time. The simulation results show that all the classical kinetic models underestimate the experimental results, similar to the models used in previous work on coal gasification by SCW. The underestimation of the models results from the catalytic effect of alkaline earth metals (AAEMs), which can notably increase the active sites of gasification reaction without changing the gasification kinetic mechanism. To solve the above problem, the catalytical effect to describe the kinetic behavior of the SCWG of FW is considered and a semiempirical modified random pore model (MRPM) is developed based on the RPM model. The simulation results of the MRP models are close to experimental findings, indicating that MRP model can be used to predict the entire process of SCWG under different conditions without dividing gasification into different stages of reaction. The MRP model can also be used for the prediction of SCWG of coal, biomass, and organic wastes and is crucial to reactor optimization and scaling up.

Hydrogenation properties of Mg17Al12 doped with alkaline-earth metal (Be, Ca, Sr and Ba)

Based on density functional theory (DFT), the effects of alkaline-earth metal (AM) on the hydrogenation properties of the Mg-Al alloy are investigated. The related geometry structure, formation energy, H adsorption energy and electronic structure of the AM-doped (AM = Be, Ca, Sr and Ba) bulk Mg17Al12 alloy and Mg17Al12(110) surface are calculated. Results show that the improved hydrogenation properties of the AM-doped Mg17Al12(110) surface are achieved. Moreover, the adsorption energy of H on the Be-doped surface (−0.79 eV) is more excellent than that on the transition metal Ni-doped (−0.44 eV), light metal Li-doped (−0.33 eV) and clean (−0.18 eV) Mg17Al12(110) systems. Analysis of the electronic structures reveals that the Be-H, Ca-H, Sr-H and Ba-H bonds are formed at the same time with the generation of Mg-H bond. Be-H bond is strongest, followed by the Ba-H whose H adsorption energy (−0.31 eV) is also second. Our theoretical predictions may provide a way for hydrogenation of the Mg-Al alloy in experiments.

Effects of alkaline earth metals on the surface, structure, and reactivity of α-alumina

A series of strontium- and barium-doped alumina samples were prepared by hydrolysis, in neutral medium, starting from commercial Al2O3, SrCO3, and BaCO3 materials. The precursors thus obtained were calcined under air at 700 °C; then, the bulk and surface properties of the resulting mixed oxides were characterized by nitrogen physisorption, X-ray diffraction (XRD), hydrogen temperature-programmed reduction (H2-TPR), thermogravimetry (TGA), and differential thermal analysis (DTA). Contrary to SrCO3, an addition of BaCO3 to α-Al2O3 increases slightly the specific surface area. XRD patterns essentially reveal the characteristic reflections assigned to α-Al2O3. In agreement with TGA and XRD analysis, strontium and barium carbonates remain after calcination at 700 °C, their decomposition starting above 800 °C. Let us note that this decomposition occurs more readily on AlSr-100 than on AlBa-100 with no apparent relationship with the evolution observed on the specific surface areas. H2-TPR experiments underline a significant bulk reduction of barium and strontium carbonates taking place significantly above 900 °C with similar trend noticed during TGA regarding their thermal decomposition. However, the most relevant observation is related to a sharp enhancement of the reducibility of AlSr-y with the appearance two reduction ranges highlighting the existence of different types of interactions with strontium and the alumina substrate.