The effect of barium-promoted for microsphere Ru/CeO2 catalysts in ammonia synthesis

In this essay, the effect of the morphology of the CeO₂ support and the Ba promoter on the ammonia synthesis reaction was studied. CeO₂ support with {110} and {100} crystal planes and more oxygen vacancies enhanced the catalytic activity of ammonia synthesis. The relatively uniform microspheres structure CeO₂ support (CeO₂-MS) with {110} and {100} crystal planes was synthesized. The structural functions of the as-synthesized CeO₂ support for the Ru-based catalyst were investigated in the ammonia synthesis reaction. The results of catalytic performance showed that the catalytic activity of 2.5%Ru/CeO₂-MS catalyst reached 8940 μmol· g^?1· h^?1 at 450 ℃, 3.8 MPa, H₂/N₂ = 3 (60 mL?min^?1), which is higher nearly 2.5 times than the 2.5%Ru/CeO₂-commercial (CeO₂-C). And the catalytic activity of catalysts increased with the increase of reaction temperature. The activity of 6%Ba-2.5%Ru/CeO₂-MS (24000 μmol· g^?1· h^?1) catalyst increased about 268% than that of catalyst without addition of Ba. Their physical and chemical properties were characterized by XRD, BET, HRTEM, H₂-TPR, H₂-TPD, and XPS analyses. Our results indicate that the 2.5%Ru/CeO₂-MS catalyst and catalysts involving promoters (Cs, K, and Ba) exhibit significant support-morphology-dependent catalytic activity for ammonia synthesis.     

Enhancement of ammonia synthesis activity on La2O3-supported Ru catalyst by addition of ceria

The addition of Ce species in La₂O₃ can enhance the number of defect sites and generate the Ce_1-xLa_xO_2-δ solid solution, thereby increasing the amount of the exposed ruthenium species and proportion of metallic ruthenium species. The presence of Ce species in Ru/La₂O₃ promotes the desorption of hydrogen, and hydrogen species prefers to desorb in the H₂ molecule formation pathway. On the other hand, the difference in the Ce addition method strongly affects the exchange between the adsorbed hydrogen species on Ru catalyst with the gaseous hydrogen species. Owing to improvement of the proportion of oxygen vacancy, Ru⁰ and number of the exposure of ruthenium species, H₂ species adsorbed on Ru/LaCe–C prepared by coprecipitation method preferentially desorbs in the formation of H₂ pathway, and a large proportion of the adsorbed H species would exchange with the hydrogen species from the gaseous phase, which leads to improvement of ammonia synthesis rate by 75% in comparison with Ru/La₂O₃ catalyst.     

Oxygen vacancies and morphology engineered Co3O4 anchored Ru nanoparticles as efficient catalysts for ammonia borane hydrolysis

Developing efficient but facile strategies to modulate the catalytic activity of Ru deposited on metal oxides is of broad interest but remains challenging. Herein, we report the oxygen vacancies and morphological modulation of vacancy-rich Co₃O₄ stabilized Ru nanoparticles (NPs) (Ru/V_O-Co₃O₄) to boost the catalytic activity and durability for hydrogen production from the hydrolysis of ammonia borane (AB). The well-defined and small-sized Ru NPs and V_O-Co₃O₄ induced morphology transformation via in situ driving V_O-Co₃O₄ to 2D nanosheets with abundant oxygen vacancies or Co²⁺ species considerably promote the catalytic activity and durability toward hydrogen evolution from AB hydrolysis. Specifically, the Ru/V_O-Co₃O₄ pre-catalyst exhibits an excellent catalytic activity with a high turnover frequency of 2114 min^?1 at 298 K. Meanwhile, the catalyst also shows a high durability toward AB hydrolysis with six successive cycles. This work establishes a facile but efficient strategy to construct high-performance catalysts for AB hydrolysis.     

Influence of basic dopants on the activity of Ru/Pr6O11 for hydrogen production by ammonia decomposition

Basic oxides such as alkali metal oxides, alkaline earth metal oxides, and rare earth oxides were added to Ru/Pr₆O₁₁, and the activity of the catalysts with respect to hydrogen production by ammonia decomposition was investigated. Ru/Pr₆O₁₁ doped with alkali metal oxides, except for Li₂O, achieved higher NH₃ conversions than bare Ru/Pr₆O₁₁. Cs₂O, the most basic of the alkali metal oxides, was the most effective dopant. In contrast, other dopants with lower basicity than the alkali metal oxides achieved lower NH₃ conversions than bare Ru/Pr₆O₁₁. Changing the Cs/Ru molar ratio revealed that the best Cs/Ru ratio was 0.5–2; the reaction was effectively promoted without negative effects from coverage of the Ru surface by the Cs₂O. Varying the order of loading the Ru and Cs₂O onto Pr₆O₁₁ revealed that loading Ru onto Cs₂O/Pr₆O₁₁ was an effective way to enhance NH₃ conversion, and coverage of the Ru surface was reduced.     

Effect of reaction conditions and surface characteristics of Ru/CeO2 on catalytic performance for ammonia synthesis as a clean fuel

The impact of reaction parameters and surface characteristics on NH₃ synthesis activity of the Ru/CeO₂ catalyst was explored. An exceptionally higher NH₃ synthesis activity was observed at 375 °C and 2.5 MPa gauge pressure. The H₂/N₂ ratio among the reactants strongly affected the catalytic activity. The catalytic activity enhanced at higher temperatures for a higher H₂/N₂ ratio, while the lower H₂/N₂ ratio was suitable for improved NH₃ synthesis at a lower temperature while working at 2.5 MPa gauge pressure. Likewise, NH₃ synthesis activity of Ru/CeO₂ catalyst enhanced abruptly on increasing pressure at relatively higher temperature conditions, using a reactant flow with a higher H₂/N₂ ratio. The NH₃ synthesis activity enhanced with time on stream. This increase in activity was associated with an increase in Ru particles with high dispersion on the surface of the catalyst during NH₃ synthesis, confirmed by FIB-TEM and EDS analysis of the cross-sections of catalyst particles.     

The dispersed SiO2 microspheres supported Ru catalyst with enhanced activity for ammonia decomposition

Ru nanoparticles supported on SiO₂ microspheres (Ru/SiO₂-GUS) were prepared by the glucose-urea-metallic salt method and applied in the decomposition of ammonia. In the glucose-urea-metallic salt method, glucose as the carbon template plays a significant role in the formation of diffusion-beneficial structural properties of Ru/SiO₂-GUS, and also induceds the modification of the electronic state of Ru. Ru/SiO₂-GUS exhibited higher catalytic activity compared with the catalyst prepared with the impregnation method. The catalytic performance of Ru/SiO₂-GUS was further enhanced with the addition of either K or Cs——the addition order and amount strongly affecting the catalytic performance. When the ratio of K/Cs to Ru is 2, the alkali metal (KOH/CsOH) solution is added in the homogeneous solution of glucose, urea, RuCl₃ and the colloidal silica, the promotion effect of K/Cs is the strongest, particularly under lower reaction temperatures. However, the promotion effects of K and Cs are different as reveled by the combined results of H₂-TPR, XPS and NH₃-TPSR. More NH₃ can be absorbed on K–Ru/SiO₂-GUS and the electron density of Ru decreased. By contrast, more metallic Ru formed on Cs–Ru/SiO₂-GUS, facilitating N₂ recombination.     

Effect of noble metal addition over active Ru/TiO2 catalyst for CO selective methanation from H2 rich-streams

Selective CO methanation from H₂-rich stream has been regarded as a promising route for deep removal of low CO concentration and catalytic hydrogen purification processes. This work is focused on the development of more efficient catalysts applied in practical conditions. For this purpose, we prepared a series of catalysts based on Ru supported over titania and promoted with small amounts of Rh and Pt. Characterization details revealed that Rh and Pt modify the electronic properties of Ru. The results of catalytic activity showed that Pt has a negative effect since it promotes the reverse water gas shift reaction decreasing the selectivity of methanation but Rh increases remarkably the activity and selectivity of CO methanation. The obtained results suggest that RuRh-based catalyst could become important for the treatment of industrial-volume streams.     

Improvement in ammonia synthesis activity on ruthenium catalyst using ceria support modified a large amount of cesium promoter

A supported ruthenium catalyst (Ru/Cs⁺/CeO₂) for ammonia synthesis is described which incorporates a large amount of a Cs⁺ promoter in a porous CeO₂ support to enhance the electron donation effect of the alkali promoter on the ruthenium catalyst. Optimization of the Ru and Cs⁺ promoter contents improves the ammonia synthesis rate to more than 4 times that of the benchmark catalyst (Cs⁺/Ru/MgO) at 350 °C and 0.1 MPa, and the ammonia synthesis rate is stable for 100 h. Introduction of the Cs⁺ promoter into the support before the Ru impregnation increases the particle size of the Ru catalyst. Despite a decrease in the number of active sites, the TOF of the catalyst is more than 50 times that of Ru (2 wt%)/CeO₂. CO adsorption measurements suggest an electron donating effect by the Cs⁺ promoter to ruthenium metal. Reaction order analysis indicates this is due to a mitigation of hydrogen poisoning.     

Comparative study of oxygen reduction reaction on RuxMySez (M = Cr, Mo, W) electrocatalysts for polymer exchange membrane fuel cell

Electrochemical evaluation of the Ru_xM_ySe_z (M = Cr, Mo, W) type electrocatalysts towards the oxygen reduction reaction (ORR) is presented. The electrocatalysts were synthesized by reacting the corresponding transition metal carbonyl compounds and elemental selenium in 1,6-hexanediol under refluxing conditions for 3 h. The powder electrocatalysts were characterized by scanning electron microscopy (SEM), and X-ray diffraction (XRD). Results indicate the formation of agglomerates of crystalline particles with nanometric size embedded in an amorphous phase. The particle size decreased according to the following trend: Ru_xCr_ySe_z > Ru_xW_ySe_z > Ru_xMo_ySe_z. Electrochemical studies were performed by rotating disk electrode (RDE) and rotating ring-disk electrode (RRDE) techniques. Kinetic parameters exhibited Tafel slopes of 120 mV dec⁻¹; exchange current density of around 1 × 10⁻⁵ mA cm⁻² and apparent activation energies between 40 and 55 kJ mol⁻¹. A four-electron reduction was found in all three cases. The catalytic activity towards the ORR decreases according to the following trend: Ru_xMo_ySe_z > Ru_xW_ySe_z > Ru_xCr_ySe_z. However this trend was not maintained when the materials were tested as cathode electrodes in a single polymer exchange membrane fuel cell, PEMFC. The Ru_xW_ySe_z electrocatalyst showed poor activity compared to Ru_xMo_ySe_z and Ru_xCr_ySe_z which were considered suitable candidates to be used as cathode in PEMFCs.     

Direct high-purity hydrogen production from ammonia by using a membrane reactor combining V-10mol%Fe hydrogen permeable alloy membrane with Ru/Cs2O/Pr6O11 ammonia decomposition catalyst

The hydrogen production capabilities of the membrane reactor combining V-10 mol%Fe hydrogen permeable alloy membrane with Ru/Cs₂O/Pr₆O₁₁ ammonia decomposition catalyst are studied. The ammonia conversion is improved by 1.7 times compared to the Ru/Cs₂O/Pr₆O₁₁ catalyst alone by removing the produced hydrogen through the V-10mol%Fe alloy membrane during the ammonia decomposition. 79% of the hydrogen atoms contained in the ammonia gas are extracted directly as high-purity hydrogen gas. Both the Ru/Cs₂O/Pr₆O₁₁ catalyst and the V-10 mol% Fe alloy membrane are highly durable, and the initial performance of the hydrogen separation rate lasts for more than 3000 h. The produced hydrogen gas conforms to ISO 14687–2:2019 Grade D for fuel cell vehicles because the ammonia and nitrogen concentrations are less than 0.1 ppm and 100 ppm, respectively.     

Electrocatalytic ammonia synthesis on Fe@MXene catalyst as cathode of intermediate-temperature proton-conducting solid oxide cell

As the only carbon-free energy carrier without CO₂ emission upon decomposition, ammonia is an ideal storage medium for H₂. However, the current low efficiency of ammonia synthesis is a main challenge on intermediate-temperature proton-conducting electrochemical cells. Herein, we develop a novel non-precious cathode catalyst consisting of Fe nanoparticles loaded on two-dimensional MXene nanosheets (Fe@MXene) that can achieve a high Faradaic efficiency of 8.4% and an NH₃ yield of 8.24 × 10⁻⁹ mol. s⁻¹·cm⁻² on an anode-supported Ba_0·95Ce_0·6Tb_0·1Y_0·2Zr_0·1O_3-δ-based electrolyte. The resultant catalyst with high specific surface area and catalytic active sites is beneficial to N₂ reduction, resulting from the effective activation of N₂ molecules imposed by the transported protons. The mechanism of catalytic NRR reveals that Fe@MXene catalyst can increase the electrocatalytic efficiency because of the improvement in the reaction rate constant. These show a promising catalyst of Fe@MXene for N₂ reduction reaction using intermediate-temperature proton-conducting solid oxide cell.     

Sol-gel synthesis of Er3+:Y3Al5O12/TiO2Ta2O5/MoO2 composite membrane for visible-light driving photocatalytic hydrogen generation

By using TiO₂ and Ta₂O₅ colloids, a stable and efficient visible-light driven photocatalyst, Er³⁺:Y₃Al₅O₁₂/TiO₂Ta₂O₅/MoO₂ composite membrane, was successfully prepared via sol–gel dip coating method at room temperature. The XRD, FTIR, SEM, TEM and EDX results confirm that approximately spherical Er³⁺:Y₃Al₅O₁₂ nanoparticles were embedded in TiO₂Ta₂O₅ matrix. UV–vis absorption and PL spectra of Er³⁺:Y₃Al₅O₁₂ were also determined to confirm the visible absorption and ultraviolet emission. The photocatalytic hydrogen generation was carried out by using methanol as sacrificial reagent in aqueous solution under visible-light irradiation. Furthermore, some main influence factors such as heat-treated temperature, heat-treated time and molar ratio of TiO₂ and Ta₂O₅ on visible-light photocatalytic hydrogen generation activity of Er³⁺:Y₃Al₅O₁₂/TiO₂Ta₂O₅/MoO₂ composite membrane were studied in detail. The experimental results showed that the photocatalytic hydrogen generation activity of Er³⁺:Y₃Al₅O₁₂/TiO₂Ta₂O₅/MoO₂ composite membrane heat-treated at 550 °C for 3.0 h was highest when the molar ratio of TiO₂ and Ta₂O₅ was adopted as 1.00:0.50. And that a high level photocatalytic activity can be still maintained after four cycles. In addition, a possible mechanism for the visible-light photocatalytic hydrogen generation of the Er³⁺:Y₃Al₅O₁₂/TiO₂Ta₂O₅/MoO₂ membrane was proposed based on PL spectra.     

Formation and characterization of gray Ta2O5 and its enhanced photocatalytic hydrogen generation activity

White and gray Ta₂O₅ powders were fabricated by sol-gel and then annealed at 850 °C in air and vacuum, respectively. Analyses by Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, electron paramagnetic resonance spectroscopy, UV-visible reflectance spectroscopy, photoluminescence spectroscopy, and density functional theory calculations indicated that oxygen vacancies are formed on the surface of gray Ta₂O₅, resulting in a disordered shell and more absorption of visible light. Its surface concentration ratio of oxygen to tantalum was determined to be 2.31. It generated 48% higher photocatalytic hydrogen than that of the white one, and cycling test indicated that it remained stable during 12 h irradiation. It also exhibited higher incident photon-to-current conversion efficiency than that of white Ta₂O₅ in the wavelength range of 300–600 nm.     

Enhanced durability of Pt/C catalyst by coating carbon black with silica for oxygen reduction reaction

A platinum electrocatalyst was presented for oxygen reduction reaction that the durability to potential cycling was enhanced. It was synthesized by coating carbon black with a silica layer, followed by Pt deposition on it. To investigate the durability of the electrocatalyst, two accelerated degradation testing protocols were carried out. Carbon corrosion and platinum metal degradation properties were evaluated under the potential cycling between 1.0 and 1.5 V and between 0.6 and 0.95 V, respectively. Silica-coated catalysts (Pt/CB-SiO₂) showed better stabilities compared to the commercial Pt/C catalyst under both of the two protocols. Commercial Pt/C catalyst initially had better mass activity than silica-coated catalysts but it became similar after the potential cycling of carbon corrosion. TEM showed the platinum particle aggregation and particle density decrease especially for the commercial catalyst by the potential cycling. The silica coating prevents carbon corrosion by blocking the carbon support from direct contact with the oxygen source and preventing the effect of oxygen spillover from the platinum to carbon during the potential cycling between 1.0 and 1.5 V. It also alleviates platinum dissolution in reverse scans by reducing the formation of Pt oxide during potential cycling in between 0.6 and 0.95 V. The results suggest the coating of carbon support can enhance the durability of Pt/C catalyst to the potential cycling.     

ORR performance evaluation of Al-substituted MnFe2O4/ reduced graphene oxide nanocomposite

Active and durable oxygen reduction reaction (ORR) catalysts are of utmost importance to realize the commercialization of hydrogen fuel cells and metal-air batteries. Al-substituted MnFe₂O₄-based ternary oxide and reduced graphene oxide (MAF-RGO) nanocomposite is synthesized using an in-situ co-precipitation followed by a hydrothermal process and verified for ORR electrocatalysis in the alkaline electrolyte (0.1 M KOH). MAF-RGO is first analyzed using physicochemical characterization tools including X-ray diffraction, Raman spectroscopy, sorption studies, electron microscopy, X-ray photoelectron spectroscopy, etc. Further, the characteristic ORR peak centered at 0.56 V vs. reversible hydrogen electrode (RHE) in cyclic voltammetry (CV) studies confirms the electrocatalytic performance of MAF-RGO. The ORR onset potential of 0.92 V vs. RHE is obtained in linear sweep voltammetry (LSV) measurement at 1600 rpm in O₂-saturated electrolyte exhibiting an improved ORR performance as compared to the commercial electrocatalyst. The reduction kinetics is observed to follow the desirable near 4-e^- mechanism. In addition, the electrocatalyst exhibits improved relative current stability of 86% and methanol poisoning resistance of 82%, which is better in comparison to the standard Pt/C. The observed electrochemical performance results from the synergism between the oxygen vacancy-rich Al-substituted metallic oxide active species and the functional group enriched predominantly mesoporous RGO sheets with excellent electrical conductivity. The introduction of metallic species enhanced the inter-planar spacing between graphitic sheets easing the maneuver of reactant species through the electrocatalyst and accessing more ORR-active sites. This study establishes the potency of mixed transition metal oxide/nanocarbon composites as durable high-performance ORR-active systems.     

One-pot synthesis of supported Ni@Al2O3 catalysts with uniform small-sized Ni for hydrogen generation via ammonia decomposition

Nickel based materials are the most potential catalysts for CO_x-free hydrogen production from ammonia decomposition. However, the facile synthesis of supported Ni-based catalysts with small size Ni particles, high porosity and good structural stability is still of great demand. In this work, uniform small-sized Ni particles supported into porous alumina matrix (Ni@Al₂O₃) are synthesized by a simple one-pot method and used for ammonia decomposition. The Ni content is controlled from 5 at.% to 25 at.%. Especailly, the 25Ni@Al₂O₃ catalyst shows the best catalytic performance. With a GHSV of 24,000 cm³g_cat^?1h^?1, 93.9% NH₃ conversion is achieved at 600 °C and nearly full conversion of NH₃ is realized at 650 °C. The hydrogen formation rate of 25NiAl catalyst reaches 3.6 mmol g_cat^?1min^?1 at 400 °C and 7.8 mmol g_cat^?1min^?1 at 450 °C. The enhanced activity observed on 25Ni@Al₂O₃ catalyst can be attributed to the structural characteristic that large amounts of uniform-sized small (7.2 ± 0.9 nm) Ni particles are highly dispersed into porous alumina matrix. The aggregation of active metallic Ni particles during the high temperature reaction can be effectively prevented by the porous alumina matrix due to the strong interaction between them, thus ensuring a good catalytic performance.     

Solution plasma-assisted preparation of highly dispersed NiMnAl-LDO catalyst to enhance low-temperature activity of CO2 methanation

In this work, the solution plasma-assisted method was used to prepare NiMnAl-LDO (layered double oxides) catalysts with different treatment times, which were used for the CO₂ methanation reaction. Solution plasma treatment can enhance the dispersibility of the catalyst, create oxygen defects and improve the chemical adsorption capacity of the catalyst. The results show that the low-temperature activity of the catalyst has been improved after the solution plasma treatment. We demonstrate that the NiMnAl-LDO-P(20) catalyst with high dispersion has the highest catalytic activity in CO₂ methanation (81.3% CO₂ conversion and 96.7% CH₄ selectivity at 200 °C). Even though working for 70 h, the catalyst is still highly stable. This work provides a great promise for improving the low-temperature activity of Ni-based catalysts.     

Effect of preparation methods on the catalyst performance of Co/MgLa mixed oxide catalyst for COx-free hydrogen production by ammonia decomposition

This work deals with the effect of catalyst preparation method of the mixed Co, Mg and La oxide catalysts on their structure and catalytic properties for ammonia decomposition. Two methods are used for catalysts preparations impregnation and co-precipitation (in air and in pure O₂ atmosphere), The Mg/La = 2 molar ratio and 5 wt% of cobalt content was maintained same in all catalysts. The catalyst performance was evaluated in the temperature range 300–550 °C at atmospheric pressure. The prepared catalysts were characterized by BET, XRD, TPR, XPS, CO₂-TPD and SEM techniques. No pronounced differences were observed in BET among the catalysts. It was found that the 5CML-OXY (5 wt%Co over MgLa catalyst prepared by co-precipitation method in oxygen atmosphere) has superior activity among the other catalysts. This could be attributed to availability of easily reducible cobalt species determined by TPR studies and enhanced interaction between Mg and La determined by SEM and XPS. The moderate basic site density determined by CO₂-TPD results was also increased in 5CML–OXY catalysts compared with other catalysts. These consequences are might be one of the reasons for enhanced activity of 5CML–OXY catalyst compared to other catalysts. Hence catalyst preparation by co-precipitation in oxygen atmosphere is the best method which might be one of the parameters that influenced on catalytic properties of the cobalt on MgOLa₂O₃ system, for ammonia decomposition.     

One-step synthesis of Ni/yttrium-doped barium zirconates catalyst for on-site hydrogen production from NH3 decomposition

On-site produced hydrogen from ammonia decomposition can directly fuel solid oxide fuel cells (SOFCs) for power generation. The key issue in ammonia decomposition is to improve the activity and stability of the reaction at low temperatures. In this study, proton-conducting oxides, Ba(Zr,Y) O_3-δ (BZY), were investigated as potential support materials to load Ni metal by a one-step impregnation method. The influence of Ni loading, Ba loading, and synthesis temperature, of Ni/BZY catalysts on the catalytic activity for ammonia decomposition were investigated. The Ni/BZY catalyst with Ba loading of 20 wt%, Ni loading of 30 wt%, and synthesized at 900 °C attained the highest ammonia conversion of 100% at 600 °C. The kinetics analysis revealed that for Ni/BZY catalyst, the hydrogen poisoning effect for ammonia decomposition was significantly suppressed. The reaction order of hydrogen for the optimized Ni/BZY catalyst was estimated as low as ?0.07, which is the lowest to the best of our knowledge, resulting in the improvement in the activity. H₂ temperature programmed reduction and desorption analysis results suggested that a strong interaction between Ni and BZY support as well as the hydrogen storage capability of the proton-conducting support might be responsible for the promotion of ammonia decomposition on Ni/BZY. Based on the experimental data, a mechanism of hydrogen spillover from Ni to BZY support is proposed.     

Optimizing electronic state in Sr2Co2O5-x with ferromagnetic state by improving oxygen vacancies for oxygen evolution reaction

The eg occupancy in perovskite oxides plays a crucial role for the oxygen electrocatalysis. Herein, we demonstrated a new method to optimize the eg filling and electronic-state of Co ions in Sr₂Co₂O_5-x (SCO) via altering concentrations of oxygen vacancies using the CaH₂ as reductant in an evacuated (≈10^?2 Pa) pyrex tube. As the oxygen vacancies concentration increased, the eg electron filling of SCO was optimized and its conductivity was greatly improved. Notably, the electronic state of SCO changed from antiferromagnetic (AFM) to ferromagnetic (FM) state. Moreover, the SCO exhibited a remarkable activity toward oxygen evolution reaction (OER), with a low overpotential of 320 mV and a tafel slope of 65 mV dec^?1, which is superior to most well-known perovskite oxides catalysts. The theoretical calculations demonstrated that oxygen vacancies could reduce the energy barrier of OER process. This work not only establishes a clear relationship among oxygen vacancies, eg filling, magnetic behavior and OER performance, but also provides a new method for designing highly activity efficient catalysts for OER.