Platinum-catalyzed Nb–doped TiO2 and Nb-doped TiO2 nanotubes for hydrogen generation in proton exchange membrane water electrolyzers

This paper studies the catalytic activity of Pt deposited onto Nb-doped titania supports toward the hydrogen evolution reaction (HER). New catalysts based on Nb-doped TiO₂ nanoparticles (nNb-TiO₂) and Nb-doped TiO₂ nanotubes (nNb-TNTs), with n in the range 3–10 at % (Nb + Ti), were synthesized. The specific surface areas of nNb-TNTs were 250–300 m²g^-1, about three times higher than those of nNb-TiO₂. X-ray diffraction showed the Nb incorporation into the TiO₂ lattice with its consequent lattice expansion. The X-ray photoelectron spectra of Pt deposited onto Nb-doped titania revealed a negative charge accumulation on Pt, thus denoting strong metal-support interaction. The electrochemical characterization in acidic media showed that Pt supported on nNb-TiO₂ and nNb-TNTs presented better activity toward the HER than that of Pt deposited onto the un-doped supports and commercial Pt on carbon. The best performance was obtained with a small Nb doping of 3 at %.     

Highly carbon– and sulfur–tolerant Sr2TiMoO6−δ double perovskite anode for solid oxide fuel cells

Ni-based cermets are most commonly used anode materials for solid-oxide fuel cells (SOFCs), but poor stability operating on hydrocarbon fuels seriously hampers their commercialization due to carbon deposition and sulfur poisoning. Here, we report a carbon– and sulfur–tolerant double perovskite anode Sr₂TiMoO_6−δ (STMO) combining the characteristics of two simple perovskites of SrTiO₃ and SrMoO₃. The STMO anode exhibits excellent thermal and chemical compatibility with La_0.9Sr_0.1Ga_0.8Mg_0.2O_3–δ (LSGM) and Ce_0.8Sm_0.2O_1.9 (SDC) electrolytes in 5% H₂/Ar. The single cell with STMO anode demonstrates good stability and excellent coking resistance and sulfur tolerance in H₂S-containing syngas during a 60-h period. The maximum power density (P_max) values of a LSGM-electrolyte-supported single cell with STMO anode are 505 and 275 mW cm⁻²at 850 °C in H₂ and H₂S-containing syngas, respectively. The electrochemical performance is further improved by impregnation of Pd nanoparticles, where the P_max values achieve 1009 and 586 mW cm⁻² at 850 °C under the same conditions, respectively, showing great potential as an anode material for SOFCs operating on H₂S-containing syngas. Our study provides a strategy to develop versatile double perovskite materials by combining the relevant characteristics of two separate perovskites.     

Mechanism for electrochemical reduction of Zr(IV) in molten NaCl–KCl

The electrochemical behavior of Zr (IV) at molybdenum and nickel electrodes was investigated by cyclic voltammetry, square-wave voltammetry, chronoamperometry, and chronopotentiometry at 1023 K to investigate the mechanism through which zirconium was electrochemically reduced. The number of electrons transferred in the two-step reduction of Zr(IV) at a molybdenum electrode in molten NaCl–KCl was calculated from the square-wave voltammetry results. Zr(IV) reduction to Zr (0) was found to be a two-step reaction described by the equations Zr(IV)+2e^?→Zr(II) and Zr(II)+2e^?→Zr (0). The diffusion coefficient for the transfer of Zr(IV) to the molybdenum electrode in molten NaCl–KCl was calculated from the chronoamperometry results. The phase and structure of the product of Zr(IV) reduction at a nickel electrode were determined by X-ray diffractometry and by scanning electron microscopy with energy dispersive X-ray spectroscopy, and a NiZr intermetallic compound was found.     

Synthesis and characterization of Nd0.6Sr0.4Co1−yMnyO3−δ (0 ≤ y ≤ 1.0) cathodes for intermediate temperature solid oxide fuel cells

Nd_0.6Sr_0.4Co_1−yMn_yO_3−δ (0 ≤ y ≤ 1.0) oxides have been investigated as cathode materials for intermediate temperature solid oxide fuel cells (SOFC). The samples form a single-phase solid solution with an orthorhombic perovskite structure and the lattice parameters and volume increase with increasing Mn content y. The degree of oxygen loss at high temperatures and the thermal expansion coefficient (TEC) decrease with increasing y due to a stronger MnO bond. The electrical conductivity decreases with y and the system exhibits a metal to semiconductor transition at around y = 0.2. The electrocatalytic activity and power density measured with single cell SOFC decrease with increasing y due to a decrease in oxygen exchange and mobility as well as charge transfer kinetics, arising from a decrease in the oxide ion vacancy concentration and electrical conductivity.     

Defects evolution of Ca doped La2NiO4+δ and its impact on cathode performance in proton-conducting solid oxide fuel cells

As a typical Ruddlesden-Popper oxide, La₂NiO_4+δ draws special attention for its high oxygen ion conducting behavior and special interstitial oxygen defects which enables it a promising electrocatalyst toward oxygen reduction reaction. In this work, Ca-doped La₂NiO_4+δ samples are prepared and their structure and defect evolution are investigated as Ca content. Electrical conductivity and electron conduction relaxation (ECR) investigations suggest that La_1.9Ca_0.1NiO_4+δ has the great electronic conductivity and the highest oxygen surface exchange coefficient and oxygen bulk diffusion coefficient at intermediate temperatures. These results may imply that more gas oxygen has inserted into La_1.9Ca_0.1NiO_4+δ sample, suggesting the native interstitial oxygen defects in it. X-ray photon spectroscopy (XPS) results confirm that La_1.9Ca_0.1NiO_4+δ have more active oxygen species when compared with La₂NiO_4+δ and La_1.8Ca_0.2NiO_4+δ. The great oxygen exchange and bulk diffusion properties along with its great stability in steam involved atmosphere enables it a promising for cathode for H–SOFCs. Compared with that using La₂NiO_4+δ cathode, peak powder density of H–SOFC using La_1.9Ca_0.1NiO_4+δ single phase cathode improves about 30.5% at 700 °C, suggesting that accelerating oxygen reduction reaction can effectively improve cathode performance of H–SOFCs.     

Study on the role of Pt and Pd in Pt–Pd/TiO2 bimetallic catalyst for H2 oxidation at room temperature

The hydrogen safety issue is spotlighted as the hydrogen process is extended. For this reason, we studied catalysts for H₂ oxidation at room temperature to ensure hydrogen safety. Catalysts were prepared by different preparation methods and compared to evaluate the role of Pt and Pd in Pt–Pd/TiO₂ catalysts. The catalytic activity was significantly enhanced when activity metal size was small and it was exposed to catalyst surface to a high Pd ratio. For the 0.1%Pt-0.9%Pd/TiO₂ catalyst, high hydrogen conversion of 90% was obtained under the condition of 0.5% hydrogen injection. To understand the correlation between activity and characteristics of catalyst, the physicochemical characteristics of the various catalysts were investigated by X-ray photoelectron spectroscopy (XPS), temperature-programmed oxidation and reduction (TPOR) and Field Emission-Transmission Electron Microscope (FE-TEM) analysis. From these analysis, it was found that Pt served the role of highly dispersion of active metal (Pt–Pd) and as with increasing Pd ratio of active metal, hydrogen activity was increased, which indicates that hydrogen oxidation had proceeded on the Pd site. Finally, the valence state of the Pd influenced hydrogen oxidation activity of Pt–Pd/TiO₂, which increased with increasing ratio of Pd⁰/Pd_Total.     

Stability and kinetics of powder-type and pellet-type iron (III) oxide catalysts for sulfuric acid decomposition in practical Iodine–Sulfur cycle

The efficiency of sulfuric trioxide decomposition strongly affects to the overall efficiency of the Iodine–Sulfur (IS) cycle, because the decomposition process is highly endothermic and most energy-consuming process. Therefore, we carefully selected iron (III) oxide (Fe₂O₃) for high temperature decomposition on the assumption of commercialization considering its proper activity, stability and price. This study starts with collecting the very basic empirical data as well as considering practical implications for actual design. Experimental results of stability test with Fe₂O₃ powder showed that over 65% of SO₃ conversion was secured during 110 h operation. We experimentally investigated the effects related to the weight hourly space velocity (WHSV) and gas inlet composition to SO₃ conversion with pellet-type catalyst in the temperature range of 730–910 °C. Reaction order of SO₃ decomposition was empirically verified as first-order reaction. The activation energy was also obtained as 141.4 kJ/mol under four different WHSV values.     

Investigating the electrochemical performance of Nd1-xSrxCo0.8Fe0.2O3−δ (0 ≤ x ≤ 0.85) as cathodes for intermediate temperature solid oxide fuel cells

Perovskite-type structure oxides with the nominal chemical composition Nd_1-xSr_xCo_0.8Fe_0.2O_3−δ (0 ≤ x ≤ 0.85) (NSCF) were synthesized by solid-state method to investigate the effect of Sr-doping on the crystal structure and electrochemical performance in the intermediate temperature range of 600 °C–750 °C. The electrical conductivity of the sintered NSCF pellets was found to be in the range of 300–1000 S cm⁻¹. All the NSCF compositions showed a transition from semiconducting to metallic behavior with an increase in temperature. NSCF showed reactivity with the La_0.8Sr_0.2Ga_0.8Mg_0.2O_3−δ (LSGM) electrolyte. The electrochemical performance was tested by preparing the symmetrical cells with the configuration 70 wt% NSCF +30 wt% LSGM using LSGM electrolyte in the temperature range of 650–800 °C. AC-impedance results showed a decrease in polarization resistance (Rp) of the cathode with increase in Sr-doping due to increase in electrical conductivity. Among the samples studied, composite electrode of Nd_0.3Sr_0.7Co_0.8Fe_0.2O_3−δ – LSGM showed the lowest area specific resistance (ASR) of 0.1 Ω cm² at 750 °C in air. It was chosen to investigate the effect of pO₂ on the electrochemical performance of the cathode to determine the rate determining step (RDS) in oxygen reduction reaction (ORR). Dissociation of molecular oxygen into oxygen atoms seems to be the RDS in the ORR.     

Unusual adsorption behavior of hydrogen molecules on Zr–doped perfect and oxygen–vacancy defective rutile TiO2(110) surfaces: Periodic DFT study

Adsorptions of Zr atom onto the perfect rutile TiO₂(110) and the oxygen vacancy rutile TiO₂ (110) ([TiO₂+V_o]) to form Zr–TiO₂ and Zr‒[TiO₂+V_o] were studied using periodic density functional theory (DFT) method. Three configurations of both Zr–TiO₂ and Zr‒[TiO₂+V_o] surfaces were found and binding energies of Zr atom of the most stable Configurations of Zr–TiO₂ and Zr‒[TiO₂+V_o] surfaces are respectively −3.36 and −3.26 eV. The most stable Configurations of the Zr–TiO₂ and Zr‒[TiO₂+V_o] surfaces were selected in hydrogen adsorption study. Adsorption energies of single H₂ molecule on the most stable Zr–TiO₂ and Zr‒[TiO₂+V_o] are −1.43 and −1.45 eV, respectively. Based on the second H₂ molecular adsorption on the hydrogen pre‒adsorbed Zr–TiO₂ and Zr‒[TiO₂+V_o] surfaces, adsorption energies of −1.90 and −2.55 eV were found, respectively. The second H₂ molecule adsorption was found to be much stronger than the first H₂ molecule adsorbed onto the Zr–TiO₂ and Zr‒[TiO₂+V_o] surfaces by 32.9% and 75.9%, respectively. Either the Zr–TiO₂ or Zr‒[TiO₂+V_o] surface is suggested as hydrogen–storage material and the Zr–TiO₂ can be proposed as an electrical resistance‒based hydrogen sensor.     

Ruthenium substituted pyrochlore metal oxide catalysts Y2Ce2-xRuxO7-δ (x = 0–0.4) for oxidative steam reforming of ethanol

Metal oxides Y₂Ce_2-xRu_xO_7-δ (x = 0–0.4) with partial substitution of Ruⁿ⁺ cations in the host structure were synthesized to study their catalytic activity on oxidative steam reforming of ethanol (OSRE). The samples were characterized using X-ray diffraction (XRD), X-ray photoelectron spectra (XPS) and temperature-programmed reduction (TPR). The performances investigated by varied temperatures, Ru ion content, carbon-to-oxygen ratios and long-term stability. The lowest activation temperature on OSRE is 300 °C, which is significantly lower than that of La₂Ce_2-xRu_xO_7-δ (400 °C). The cell dimension of Y₂Ce_2-xRu_xO_7-δ was reduced compare to La₂Ce_2-xRu_xO_7-δ for the replacement of the Y³⁺ ion with La³⁺ ion. The reduced unit cell in the host structure not only increase the surface composition of the Ce⁴⁺ ions, but also induce the synergetic effect of Ruⁿ⁺/Ru⁴⁺ (n > 4) and Ce⁴⁺/Ce³⁺, which lead to the enhanced OSRE activity. The optimized catalyst Y₂Ce_1.6Ru_0.4O_7-δ showed selectivity of hydrogen S_H2 = 84(4)% (Y_H2 = 2.5(1) mol/mol EtOH) and carbon monoxide S_CO = 48(1)% for long-term stability test at T = 300 °C, C/O = 0.5, and O₂/C₂H₅OH = 1.5.     

Reactivity and stability of Zr–doped CeO2 for solar thermochemical H2O splitting in combination with partial oxidation of methane via isothermal cycles

Ceria-based oxides have attracted a lot of attention as an attractive redox material because of their large capacity for storing and releasing oxygen in the solar-driven thermochemical water splitting (STWS) process. Nevertheless, the extremely high temperatures and low oxygen partial pressure required to achieve deep degrees of reduction and large temperature swing in a redox cycle introduce challenges in the practical implementation. These above challenges can be addressed in a unique way by integrating partial oxidation of methane into the reduction step. The STWS can therefore operate isothermally at significantly lower temperatures. In this work, the CeO₂-ZrO₂ solid solutions (Ce_1-xZr_xO₂) are synthesized, characterized, and assessed for thermochemical water splitting in combination with partial oxidation of methane. Up to 160 consecutive redox cycles are also conducted in a bench-scale fixed bed. At an operating temperature of 900 °C, methane successfully promotes the reduction of Ce_1-xZr_xO₂ to produce the synthesis gas with a 2:1H₂/CO ratio and 87.86% selectivity. When compared to CeO₂, the thermodynamic fuel generation capability of CeO₂ with Zr⁴⁺ doping is three times greater in the partial oxidation of methane step and water splitting step. Ce_0.8Zr_0.2O₂ (C8Z2) demonstrates the best redox activity in terms of CO and H₂ production in a redox cycle among the various Zr⁴⁺ doping levels. After 160 consecutive redox cycles, C8Z2 is also very robust, maintaining its redox activity. The C8Z2 composite redox solid solution thus exhibits excellent redox activity and long-term redox stability, potentially making it appropriate for STWS in combination with partial oxidation of methane.     

Investigation of synthesized Fe2O3 and CuO–Fe2O3 for pure hydrogen production by chemical-loop reforming of methanol in a micro-channel reactor

Production of pure hydrogen from methanol was investigated by the chemical looping method in the presence of 0.1CuO–Fe2O3 and Fe2O3 at 350 °C in a micro-channel reactor. The x-ray diffraction and atomic absorption spectroscopy analysis confirmed the formation phases and the values of Fe2O3 and CuO.Considering the formation of coke due to methanol conversion reactions and as a result, the production of CO together with H2, the time of the reduction step (2 hours-11 min) has been controlled to minimize coke deposition. The results show that coke deposition was prevented by optimizing the reduction time to 11 min for both samples and the pure H2 flow was generated for fuel cell applications, which was 231.1% higher for the 0.1CuO–Fe2O3. Although the results show that improving the Cu content and the reduction temperature increases the reduction degree of the catalyst and yield of H2, but coke deposition cannot be prevented.     

Surface defect and rational design of TiO2−x nanobelts/ g-C3N4 nanosheets/ CdS quantum dots hierarchical structure for enhanced visible-light-driven photocatalysis

TiO_2-x/g-C₃N₄/CdS ternary heterojunctions are fabricated through thermal polymerization-chemical bath deposition combined with in-situ solid-state chemical reduction approach. The prepared materials are characterized by X-ray diffraction, Fourier transform infrared spectra, scanning electron microscopy, transmission electron microscopy, nitrogen adsorption-desorption, and X-ray photoelectron spectroscopy. The results show that the ternary heterojunctions are formed successfully and CdS quantum dots (QDs) and TiO₂ are anchored on surface of g-C₃N₄ nanosheets simultaneously. The visible-light-driven photocatalytic degradation ratio of Bisphenol A and hydrogen production rate are up to 95% and ∼254.8 μmol h⁻¹, respectively, which are several times higher than that of pristine TiO₂. The excellent visible-light-driven photocatalytic activity can be ascribed to the synergistic effect of TiO_2−x, g-C₃N₄ and CdS QDs which extend the photoresponse to visible light region and favor the spatial separation of photogenerated charge carriers.     

Structural and electrochemical characterization of YBa(Fe,Co,Cu)2O5+δ layered perovskites as cathode materials for solid oxide fuel cells

Single- and double-doped YBa(Fe,Co,Cu)₂O_5+δ layered perovskites are prepared by solid state reaction method and their structural characteristics, thermal expansion coefficient, oxygen nonstoichiometry, electrical conductivity, and electrochemical performance are comparatively studied. The substitution of Co by Fe or/and Cu significantly improves thermal expansion properties as compared to undoped YBaCo₂O_5+δ. Electrochemical tests demonstrate the promising performance of synthesized materials as cathode materials at intermediate temperatures. Single doped YBaCuCoO_5+δ cathodes reveal the lowest polarization resistance equal to 0.24 and 0.78 Ω cm² at P(O₂) P^?1 = 0.2 at temperature of 800 and 700 °C, respectively.     

The elevated temperature performance of LiMn2O4 coated with LiNi1−XCoXO2 (X = 0.2 and 1)

The surface coating of LiMn₂O₄ using a gel precursor of LiNi_1−XCo_XO₂ (X=0.2 and 1) prepared from a solution-based chemical process was attempted in order to enhance the electrochemical performances of LiMn₂O₄ at elevated temperature. After the surface of LiMn₂O₄ was coated with LiNi_1−XCo_XO₂ (X=0.2 and 1) coating solution and heated at 750 °C, the surface of LiMn₂O₄ was covered with fine LiNi_1−XCo_XO₂ (X=0.2 and 1) particles. LiNi_1−XCo_XO₂ (X=0.2 and 1)-coated LiMn₂O₄ showed an excellent capacity retention at 65 °C compared to pure LiMn₂O₄. While pure LiMn₂O₄ retained 81% of the initial capacity after storage in the discharged state at 65 °C for 300 h, LiCoO₂-coated LiMn₂O₄ showed no capacity loss. The improvement of storage performance at 65 °C is attributed to the suppression of electrolyte decomposition and the reduction of Mn dissolution resulting from encapsulating the surface of LiMn₂O₄ with LiCoO₂. The surface coating with LiNi_0.8Co_0.2O₂ also enhanced the high temperature cycle performance of LiMn₂O₄. Consequently, It is proposed that the surface encapsulation of LiMn₂O₄ with fine LiNi_1−XCo_XO₂ (X=0.2 and 1) particles improve its high temperature performance.     

Sucrose-nitrate auto combustion synthesis of Ce0.85Ln0.10Sr0.05O2-δ (Ln = La and Gd) electrolytes for solid oxide fuel cells

Nanocrystalline powders of co-doped ceria oxides Ce_0.85La_0.10Sr_0.05O_2-δ (CLSO) and Ce_0.85Gda_0.10Sr_0.05O_2-δ (CGSO) have been synthesized by auto combustion method at 100°C using sucrose as fuel. Thermal analysis (TGA/DSC) of as-prepared powders indicated calcination above 400°C to remove organic residue. The average grain size of the pellets sintered at 1200°C for 4 hours is 436 and 683 nm for CLSO and CGSO, respectively. The electrical conductivity of the sintered samples was determined by impedance measurements in the temperature range 300°C to 600°C and the frequency range 20 Hz to 2 MHz. At 600°C, the total electrical conductivity (σ_t) of CGSO is 6.78 × 10⁻³ S cm⁻¹, 2.5 times higher than 2.72 × 10⁻³ S cm⁻¹ of CLSO. Further, it is found that the value of grain boundaries blocking factor (α_gb) of CGSO is 0.47 which is 30% lesser than 0.68 of CLSO at 600°C. The higher value of electrical conductivity of CGSO as compared to CLSO is attributed to the lesser blocking effect of grain boundaries, smaller lattice distortion and denser microstructure of CGSO as compared to CLSO. The electrical conductivity of synthesized samples has been compared with the electrical conductivity of similar compositions of co-doped CeO₂ oxides. Our study indicated that the sintering temperature, and hence, the morphology of sintered samples has a significant role in determining the electrical conductivity. The presence of oxygen vacancies in the synthesized samples is experimentally supported by using UV-visible spectroscopy, Raman spectroscopy, and thermal analysis techniques.     

Synthesis and characterization of lithium aluminum-doped spinel (LiAlxMn2−xO4) for lithium secondary battery

LiAl_xMn_2−xO₄ has been synthesized using various aluminum starting materials, such as Al(NO₃)₃, Al(OH)₃, AlF₃ and Al₂O₃ at 600–800°C for 20 h in air or oxygen atmosphere. A melt-impregnation method was used to synthesize Al-doped spinel with good battery performance in this research. The Al-doped content and the intensity ratio of (3 1 1)/(4 0 0) peaks can be important parameters in synthesizing Al-doped spinel which satisfies the requirements of high discharge capacity and good cycleability at the same time. The decrease in Mn³⁺ ion by Al substitution induces a high average oxidation state of Mn ion in the LiAl_xMn_2−xO₄ material. The electrochemical behavior of all samples was studied in Li/LiPF₆-EC/DMC (1:2 by volume)/LiAl_xMn_2−xO₄ cells. Especially, the initial and last discharge capacity of LiAl_0.09Mn_1.97O₄ using LiOH, Mn₃O₄ and Al(OH)₃ complex were 128.7 and 115.5 mAh/g after 100 cycles. The Al substitution in LiMn₂O₄ was an excellent method of enhancing the cycleability of stoichiometric spinel during electrochemical cycling.     

Determination of the impedance contributions in anode supported solid oxide fuel cells with (La,Sr)(Co,Fe)O3−δ cathode

In this work, anode supported solid oxide fuel cells based on Ni/YSZ anode, 8YSZ electrolyte and (La, Sr)(Co, Fe)O_3−δ cathode were analyzed by Electrochemical Impedance Spectroscopy (EIS) with the aim to identify the main electrochemical mechanism contributing to the polarization resistance. The method was validated by performing EIS analyses on reference samples at different temperatures and overvoltages. In order to investigate the different electrochemical contributions to the polarization resistance, the study was carried out by testing the cells at different operating conditions (gas partial pressure, occurrence of H₂S impurities, temperature) and considering different cells materials and microstructure (current collecting layer, diffusion barrier layer). The comparison of the different Nyquist plots, Bode plots and fitting results allows identifying the main electrochemical mechanisms occurring at the anode and the cathode and contributing to the polarization resistance of the cell. The main mechanisms associated to the anode were observed at ca. 0.1 Hz (fuel partial pressure) and ca. 600 Hz (anode charge transfer reaction). The anode contribution at low frequency (0.01–0.1 Hz) is particularly noticeable under methane internal steam reforming condition. Cathode contributions such as oxygen gas conversion and oxygen surface diffusion have been identified at ca. 0.02 Hz and 2–4 Hz, respectively.     

Preparation and characterization of amine-terminated delafossite type oxide,CuMnO2–NH2, supported Pd (0) nanoparticles for the H2 generation from the methanolysis of ammonia-borane

Among the cuprous metal oxides of the delafossite type, which are generally formulated as CuMO₂ (M = Al, Cr, Fe, Ga, Mn), the most promising is the CuMnO₂ structures. CuMnO₂ material, named crednerite, is a very interesting delafossite derivative with potential applications in many fields, mainly catalyst, photoelectrochemical cells and multiferroic tools. Herein, we report fabrication, characterization, and application of amine-terminated CuMnO₂ (CuMnO₂–NH₂) supported palladium nanoparticles (Pd/CuMnO₂–NH₂) as highly efficient and recyclable catalysts for the hydrogen production from the methanolysis of ammonia-borane (AB). The results of characterization using P-XRD, TEM, HRTEM, TEM-EDX, XPS, SEM, SEM-elemental mapping, and ICP-OES disclose that Pd (0) nanoparticles were well spread on the surface of CuMnO₂–NH₂ with a mean particle size of 3.91 ± 0.33 nm. Pd/CuMnO₂–NH₂ shows high catalytic activity in the methanolysis of AB with an initial turnover frequency of 146.68 min^?1 at 25 ± 0.1 °C which is one of the highest values ever reported for AB methanolysis in the literature. Besides, the extreme stability of Pd/CuMnO₂–NH₂ takes it a recyclable heterogeneous catalyst in this catalytic conversion.