Selective Catalysts Research Articles

High stability and selectivity of butterfly pea flower extract-NiAl LDH-based catalysts in the tetracycline degradation.

Layered double hydroxide (LDH) is an applicable material that can be modified in various ways. Modifications using natural extracts fulfill the principles of "green chemistry." The preparation of butterfly pea flower extract (BPE)-modified NiAl LDH was completed using the calcination and restacking method. The characteristics of the prepared composites were identified through analysis of functional groups, crystal phase, bandgap energy, surface area and surface morphology. Fourier transform-infrared (FT-IR) characterization revealed that the active group of the catalyst is -OH except for NiAl layered double oxide (LDO), which has the metal oxide-like functional groups. X-ray diffraction patterns expressed a typical layered material structure of NiAl LDH dan NiAl LDH-BPE, but not for NiAl LDO and NiAl LDO-BPE. Introducing BPE into NiAl LDH and NiAl LDO effectively decreased the bandgap energy and changed the surface morphology. The prepared catalysts were applied in a batch system with pH 5 to degrade tetracycline (TC). NiAl LDO demonstrated the highest activity as a catalyst in TC degradation, with a 93.61% degradation rate. In contrast, NiAl LDO-BPE demonstrated the highest structural stability in TC degradation and repeated use, with an initial degradation percentage of 82.58% and a fifth regeneration percentage of 71.4%.

A Non‐Macrocycle Thiolate‐Based Cobalt Catalyst for Selective O2 Reduction into H2O

AbstractThe reduction of dioxygen to produce selectively H2O2 or H2O is crucial in various fields. While platinum‐based materials excel in 4H+/4e− oxygen reduction reaction (ORR) catalysis, cost and resource limitations drive the search for cost‐effective and abundant transition metal catalysts. It is thus of great importance to understand how the selectivity and efficiency of 3d‐metal ORR catalysts can be tuned. In this context, we report on a Co complex supported by a bisthiolate N2S2‐donor ligand acting as a homogeneous ORR catalyst in acetonitrile solutions both in the presence of a one‐electron reducing agent (selectivity for H2O of 93 % and TOFi=3 000 h−1) and under electrochemically‐assisted conditions (0.81 V <η<1.10 V, selectivity for H2O between 85 % and 95 %). Interestingly, such a predominant 4H+/4e− pathway for Co‐based ORR catalysts is rare, highlighting the key role of the thiolate donor ligand. Besides, the selectivity of this Co catalyst under chemical ORR conditions is inverse with respect to the Mn and Fe catalysts supported by the same ligand, which evidences the impact of the nature of the metal ion on the ORR selectivity.

Scaling-Up Microwave-Assisted Synthesis of Highly Defective Pd@UiO-66-NH2 Catalysts for Selective Olefin Hydrogenation under Ambient Conditions.

The need to develop green and cost-effective industrial catalytic processes has led to growing interest in preparing more robust, efficient, and selective heterogeneous catalysts at a large scale. In this regard, microwave-assisted synthesis is a fast method for fabricating heterogeneous catalysts (including metal oxides, zeolites, metal-organic frameworks, and supported metal nanoparticles) with enhanced catalytic properties, enabling synthesis scale-up. Herein, the synthesis of nanosized UiO-66-NH2 was optimized via a microwave-assisted hydrothermal method to obtain defective matrices essential for the stabilization of metal nanoparticles, promoting catalytically active sites for hydrogenation reactions (760 kg·m-3·day-1 space time yield, STY). Then, this protocol was scaled up in a multimodal microwave reactor, reaching 86% yield (ca. 1 g, 1450 kg·m-3·day-1 STY) in only 30 min. Afterward, Pd nanoparticles were formed in situ decorating the nanoMOF by an effective and fast microwave-assisted hydrothermal method, resulting in the formation of Pd@UiO-66-NH2 composites. Both the localization and oxidation states of Pd nanoparticles (NPs) in the MOF were achieved using high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and X-ray photoelectron spectroscopy (XPS), respectively. The optimal composite, loaded with 1.7 wt % Pd, exhibited an extraordinary catalytic activity (>95% yield, 100% selectivity) under mild conditions (1 bar H2, 25 °C, 1 h reaction time), not only in the selective hydrogenation of a variety of single alkenes (1-hexene, 1-octene, 1-tridecene, cyclohexene, and tetraphenyl ethylene) but also in the conversion of a complex mixture of alkenes (i.e., 1-hexene, 1-tridecene, and anethole). The results showed a powerful interaction and synergy between the active phase (Pd NPs) and the catalytic porous scaffold (UiO-66-NH2), which are essential for the selectivity and recyclability.

Reduction of the harmful NOx pollutants emitted from the ship engines using high-pressure selective catalytic reduction system

Various techniques are used to reduce harmful pollutants such as NOX emissions from ships. Selective catalyst reduction (SCR) systems are the most effective technique used to reduce NOX emissions. In this study, the effects of an SCR reactor on NOX emissions and performance in high-pressure selective catalytic reduction (HP-SCR) systems were investigated numerically. In numerical studies, the effects of SCR system diameter, output form, catalyst activation energy, mixing zone length, and location were investigated as parametric, and the most suitable system geometry was determined. The effects of geometric parameters and catalyst type on emission and performance such as NOX reduction, NH3 slip, velocity, and pressure loss were investigated. It was determined that with increasing system diameter, whereas the NOX reduction performance increased depending on exhaust velocity, the pressure drop decreased, and the most suitable system diameter was determined as 780 mm. Furthermore, the obtained results showed that the performance of NOX reduction decreased after 2 × 106 kJ/kmol activation energy, and the most suitable SCR output form was conical geometry. In terms of the environment, this study will contribute to achieving the UN Sustainable Development Goals such as climate action (SDG 13).

Benzoxaborole Catalyst Embedded with a Lewis Base: A Highly Active and Selective Catalyst for cis-1,2-diol Modification.

The regioselective modification of polyols allows rapid access to their derivatives, thereby accelerating the polyol-related biology and drug discovery. We previously reported that benzoxaborole is a potent catalyst for the regioselective modification of polyols containing a cis-1,2-diol structure. In this study, we developed a bifunctional benzoxaborole catalyst embedded with a Lewis base. Benzoxaborole and Lewis base groups were designed to cooperatively activate a substrate (cis-1,2-diol) and reactant (electrophile), respectively, hence lowering the reaction barrier for the cis-1,2-diol moiety. The bifunctional catalyst indeed exhibited a significantly higher catalytic activity and selectivity for cis-1,2-diol modifications rather than a benzoxaborole catalyst without a Lewis base group. Mechanistic analyses, using both experimental and theoretical methods, supported the design of our catalyst. The bifunctional catalyst reported herein would be a new tool for the straightforward synthesis of polyol derivatives.

Batch to Continuous: From Laboratory Recycle Trickle Bed Test Reactor Data to Full-Scale Plant Preliminary Design—A Case Study Based on the Hydrogenation of Resorcinol

The fine chemical and pharmaceutical sectors are starting to advocate for the use of flow chemistry due to reasons such as the environment, health and safety, efficiency, cost saving, and regulatory compliance. The use of a trickle bed or fixed bed system could replace a batch autoclave typically used for hydrogenation reactions. However, there are few studies that detail the process from laboratory proof of concept through design to commercial realization. This study, using the production of 1,3-cyclohexanedione from the catalytic hydrogenation of resorcinol as a case study, demonstrates how the laboratory-scale recycle trickle bed can be used for catalyst screening and selection. Further, design data are generated by operation over a range of design superficial velocities and operating pressures that are used to derive a design correlation that is then used to specify a single stream plant at a level of definition consistent with a Preliminary Design for capital cost estimation. Finally, the further actions required in terms of data generation to increase the level of definition and confidence to a sanction grade or final design are discussed.

From Back to Stage: Superior Cycling Stability of 2LiBH4−MgH2 Enabled by Anion Tuning

Abstract2LiBH4−MgH2 (Li‐RHC) is a potential hydrogen storage candidate with a capacity of 11.5 wt.%. However, its further application is severely limited by the long nucleation induction period and poor reversibility of end‐product. Unlike the traditional focus on the catalytical role of cation, herein, a new perspective of previously ignore anion tuning has been proposed, in which S2− bridges the reversible conversion between Li2S and MgS during de‐/hydrogenation cycling of Li‐RHC. Such conversion not only enhances the migration of Li+, leading to the rapid destabilization of B─H bonds without obvious nucleation period of MgB2, but also improves the cycling stability of Li‐RHC with capacity retention over 90% even after 50 cycles. The universal of this anion modulation has been verified, along with the matching criteria of the corresponding transition metal cation. The results highlight the contribution of anion, push anion modulation from back to stage and eventually broaden the selection of catalysts for Li‐RHC.

Tandem Electrocatalytic Reduction of Nitrite to Ammonia on Rhodium–Copper Single Atom Alloys

AbstractElectrocatalytic reduction of NO2− to NH3 (NO2RR) presents a fascinating approach for simultaneously migrating NO2− pollutants and producing valuable NH3. In this study, single‐atom Rh‐alloyed copper (CuRh1) is explored as a highly active and selective catalyst toward the NO2RR. Combined theoretical calculations and in situ FTIR/EPR spectroscopic experiments uncover the synergistic effect of Rh1 and Cu to promote the NO2RR energetics of CuRh1 through a tandem catalysis pathway, in which Rh1 activates the preliminary adsorption and hydrogenation of NO2− (NO2− → *NO2 → *NOOH → *NO), while the generated *NO on Rh1 is then transferred on Cu substrate which promotes the rate‐determining step of *NO → *NHO toward the NH3 synthesis. As a result, CuRh1 equipped in a flow cell presents an unprecedented NH3 yield rate of 2191.6 µmol h−1 cm−2 and NH3‐Faradaic efficiency of 98.9% at a high current density of 322.5 mA cm−2, as well as long‐term stability for 100 h electrolysis.

Catalytic, Spectroscopic, and Theoretical Studies of Fe4S4-Based Coordination Polymers as Heterogenous Coupled Proton-Electron Transfer Mediators for Electrocatalysis.

Iron-sulfur clusters play essential roles in biological systems, and thus synthetic [Fe4S4] clusters have been an area of active research. Recent studies have demonstrated that soluble [Fe4S4] clusters can serve as net H atom transfer mediators, improving the activity and selectivity of a homogeneous Mn CO2 reduction catalyst. Here, we demonstrate that incorporating these [Fe4S4] clusters into a coordination polymer enables heterogeneous H atom transfer from an electrode surface to a Mn complex dissolved in solution. A previously reported solution-processable Fe4S4-based coordination polymer was successfully deposited on the surfaces of different electrodes. The coated electrodes serve as H atom transfer mediators to a soluble Mn CO2 reduction catalyst displaying good product selectivity for formic acid. Furthermore, these electrodes are recyclable with a minimal decrease in activity after multiple catalytic cycles. The heterogenization of the mediator also enables the characterization of solution-phase and electrode surface species separately. Surface enhanced infrared absorption spectroscopy (SEIRAS) reveals spectroscopic signatures for an in situ generated active Mn-H species, providing a more complete mechanistic picture for this system. The active species, reaction mechanism, and the protonation sites on the [Fe4S4] clusters were further confirmed by density functional theory calculations. The observed H atom transfer reactivity of these coordination polymer-coated electrodes motivates additional applications of this composite material in reductive H atom transfer electrocatalysis.

Surface Chemistry of a [C2C1Im][OTf] (Sub)Wetting Layer on Pt(111): A Combined XPS, IRAS, and STM Study.

The concept of a solid catalyst with an ionic liquid layer (SCILL) is a promising approach to improve the selectivity of noble metal catalysts in heterogeneous reactions. In order to understand the origins of this selectivity control, we investigated the growth and thermal stability of ultrathin 1-ethyl-3-methylimidazolium trifluormethanesulfonate [C2C1Im][OTf] films on Pt(111) by infrared reflection absorption spectroscopy (IRAS) and X-ray photoelectron spectroscopy (XPS) in time-resolved and temperature-programmed experiments. We combined these spectroscopy experiments with scanning tunneling microscopy (STM) to obtain detailed insights into the orientation and adsorption geometry of the ions in the first IL layer. Furthermore, we propose a mechanism for the thermal evolution of [C2C1Im][OTf] on Pt(111). We observe an intact IL layer on the surface at temperatures below 200 K. Adsorbed [C2C1Im][OTf] forms islands, which are evenly distributed over the surface. The [OTf]- anion adsorbs via the SO3 group, with the molecular axis perpendicular to the surface. Anions and cations are arranged next to each other, alternating on the Pt(111) surface. Upon heating to 250 K, we observe changes in geometry and structural distribution. Whereas at low temperature, the ions are arranged alternately for electrostatic reasons, this driving force is no longer decisive at 250 K. Here, a phase separation of two different species is discernible in STM. We propose that this effect is due to a surface reaction, which changes the charge of the adsorbates. We assume that the IL starts to decompose at around 250 K, and thus, pristine IL and decomposition products coexist on the surface. Also, IRAS and XPS show indication of IL decomposition. Further heating leads to increased IL decomposition. The reaction products associated with the anions are volatile and leave the surface. In contrast, the cation fragments remain on the surface up to temperatures above 420 K.

Temperature-driven dynamic evolution process of Ag species on silver-loaded Zr0.2Sn0.8O2 catalyst for selective catalytic oxidation of ammonia

Silver-based catalysts are extensively utilized in the selective catalytic oxidation of ammonia (NH3-SCO). However, enhancing low-temperature activity often causes a decline in N2 selectivity, presenting a substantial challenge in balancing activity and N2 selectivity. In this work, we introduced zirconium into the SnO2 support, resulting in a significant enhancement of low-temperature activity by 200 °C for the Ag/Zr0.2Sn0.8O2 catalyst; yet, this also led to the formation of N2O at low temperatures and NOx at high temperatures. Characterizations such as XPS and in situ DRIFTS revealed that the dynamic changes of silver species driven by temperature had a profound impact on the reaction mechanism and guided the formation of different products. Below 200 °C, the predominance of Ag+ directed the imide mechanism, with the –HNO species being the key intermediate leading to the production of N2O. Above 300 °C, Ag0 became dominant, favoring the internal selective catalytic reduction (i-SCR) mechanism and the production of NOx. This work provides novel insights into improving N2 selectivity of Ag-based catalysts and contributes to a deeper understanding of the reaction mechanisms.

Reversal Effect of Phosphorus on Catalytic Performances of Supported Nickel Catalysts in Reductive Amination of 1,6-Hexanediol.

The reductive amination of 1,6-hexanediol with ammonia is one of the most promising green routes for synthesis of 1,6-hexanediamine. Herein, we developed a phosphorous modified Ni catalyst of Ni-P/Al2O3. It presented satisfactory improved selectivity to 1,6-hexanediamine in the reductive amination of 1,6-hexanediol compared to the Ni/Al2O3 catalyst. The phosphorous tended to interact with Al2O3 to form AlPOx species, induced Ni nanoparticle to be flatter, and the decrease of strong acid sites, the new-formed Ni-AlPOx-Al2O3 interface and the flatter Ni nanoparticle were the key to switch the dominating product from hexamethyleneimine to 1,6-hexanediamine. This work develops an efficient catalyst for production of 1,6-hexanediamine from the reductive amination of 1,6-hexanediol, and provides a point of view about designing selective non-noble metal catalysts for producing primary diamines via reductive amination of diols.

Biomass-based carbon aerogels with interconnected pores and controllable Zn–N sites for CO2 electroreduction

The rational design of renewable, highly active, and selective catalysts has always been the key to the practical application of CO2 electroreduction. In this study, biomass-based Zn/N doped carbon aerogels were fabricated for high-selectivity electrical reduction of CO2 to CO. After in situ Zn/N doping, carbon aerogels exhibited interconnected pores, high surface area, and exposed active sites, and their physicochemical properties are significantly affected by pyrolysis temperature. When the pyrolysis temperature increased to 950 °C, the number of surface active sites and pore structure parameters of carbon aerogels decreased significantly due to the escape of zinc and nitrogen. CAZN-850 exhibited the highest specific surface area of 1317.0 m2/g and abundant Zn–N sites, which results in its high activity and selectivity for electroreduction of CO2 to CO (FECO = 89 % at −1.0V vs. RHE). Moreover, the stability test results for CO2RR showed that the reduction value of FECO for Zn/N doped carbon aerogels was only 5 % under long-time operation. This work provides a new idea for the design of biomass-based catalysts for CO2 electroreduction.

Promoting effect of polyoxometallic acid modification on the NH3-SCR performance of Mn-based catalysts

The strong oxidation capabilities of Mn sites render Mn-based catalysts showing high activities of selective catalytic reduction (SCR) at temperatures < 250℃, but simultaneously lead to the generation of by-product N2O with strong greenhouse effect. The activity-N2-selectivity trade-off was a prevalent observation in the development of Mn-based SCR catalysts. Here, a polyoxometallic acid enhancement strategy was devised to simultaneously promote the N2 selectivity and low-temperature SCR (LT-SCR) activity of Mn-based metal oxide catalysts, where the introduction of uniformly dispersed phosphomolybdic acid (HPMo) tuned the oxidation capabilities and enhanced NH3 adsorption-storage capability of catalysts. The combination of transient reaction, in-situ DRIFTS analysis and DFT calculations revealed that the main origin of N2O on the Mn-based catalysts was the deep oxidation of NH3, which was inhibited by the interaction between HPMo and Mn sites. Additional NH3 molecules adsorbed by the abundant acid sites supplied by HPMo further facilitated the SCR reaction. This strategy could guide the design of high-activity and high-selectivity LT-SCR catalysts for industrial denitration.

Development of Fe-based catalysts for CO2 hydrogenation to higher hydrocarbons for operating in slurry reactor

The development of CO2 hydrogenation catalysts for hydrocarbon production is a challenging and relevant task as it can contribute to solving of the CO2 emission problem. In the present work, we describe our journey in the development of catalysts for operating in a slurry reactor. The screening of the preparation methods and catalyst composition yielded an active and highly selective CO2 hydrogenation catalyst with catalytic performances comparable to the best ones reported in the literature. The most perspective catalysts were successfully evaluated in CO2 hydrogenation using a slurry reactor. The supported catalysts were found to have a lower ability to form higher hydrocarbons compared to bulk catalysts. This could be correlated with the particle sizes of the active component of the respective catalysts. This insight may be useful in preparing tailor-made Fe-based catalysts with high chain growth probability. The important issue of mechanical strength for slurry operation was highlighted.

Interplay between Catalyst Corrosion and Homogeneous Reactive Oxygen Species in Electrochemical Ozone Production.

Electrochemical ozone production (EOP), a six-electron water oxidation reaction, offers promising avenues for creating value-added oxidants and disinfectants. However, progress in this field is slowed by a dearth of understanding of fundamental reaction mechanisms. In this work, we combine experimental electrochemistry, spectroscopic detection of reactive oxygen species (ROS), oxygen-anion chemical ionization mass spectrometry, and computational quantum chemistry calculations to determine a plausible reaction mechanism on nickel- and antimony-doped tin oxide (Ni/Sb-SnO2, NATO), one of the most selective EOP catalysts. Antimony doping is shown to increase the conductivity of the catalyst, leading to improved electrochemical performance. Spectroscopic analysis and electrochemical experiments combined with quantum chemistry predictions reveal that hydrogen peroxide (H2O2) is a critical reaction intermediate. We propose that leached Ni4+ cations catalyze hydrogen peroxide into solution phase hydroperoxyl radicals (•OOH); these radicals are subsequently oxidized to ozone. Isotopic product analysis shows that ozone is generated catalytically from water and corrosively from the catalyst oxide lattice without regeneration of lattice oxygens. Further quantum chemistry calculations and thermodynamic analysis suggest that the electrochemical corrosion of tin oxide itself might generate hydrogen peroxide, which is then catalyzed to ozone. The proposed pathways explain both the roles of dopants in NATO and its lack of stability. Our study interrogates the possibility that instability and electrochemical activity are intrinsically linked through the formation of ROS. In doing so, we provide the first mechanism for EOP that is consistent with computational and experimental results and highlight the central challenge of instability as a target for future research efforts.

Application of machine learning in the study of cobalt-based oxide catalysts for antibiotic degradation: An innovative reverse synthesis strategy

This study addresses antibiotic pollution in global water bodies by integrating machine learning and optimization algorithms to develop a novel reverse synthesis strategy for inorganic catalysts. We meticulously analyzed data from 96 studies, ensuring quality through preprocessing steps. Employing the AdaBoost model, we achieved 90.57% accuracy in classification and an R²value of 0.93 in regression, showcasing strong predictive power. A key innovation is the Sparrow Search Algorithm (SSA), which optimizes catalyst selection and experimental setup tailored to specific antibiotics. Empirical experiments validated SSA's efficacy, with degradation rates of 94% for Levofloxacin and 97% for Norfloxacin, aligning closely with predictions within a 2% margin of error. This research advances theoretical understanding and offers practical applications in material science and environmental engineering, significantly enhancing catalyst design efficiency and accuracy through the fusion of advanced machine learning techniques and optimization algorithms.

Validating ΔΔG Selectivity Descriptor for Electrosynthesis of H2O2 from Oxygen Reduction Reaction.

Understanding selectivity trends is a crucial hurdle in the developing innovative catalysts for generating hydrogen peroxide through the two-electron oxygen reduction reaction (2e-ORR). The identification of selectivity patterns has been made more accessible through the introduction of a newly developed selectivity descriptor derived from thermodynamics, denoted as ΔΔG introduced in Chem Catal. 2023, 3(3), 100568. To validate the suitability of this parameter as a descriptor for 2e-ORR selectivity, we utilize an extensive library of 155 binary alloys. We validate that ΔΔG reliably depicts the selectivity trends in binary alloys reported for their high activity in the 2e-ORR. This analysis also enables the identification of nine selective 2e-ORR catalysts underscoring the efficacy of ΔΔG as 2e-ORR selectivity descriptor. This work highlights the significance of concurrently considering both selectivity and activity trends. This holistic approach is crucial for obtaining a comprehensive understanding in the identification of high-performance catalyst materials for optimal efficiency in various applications.

Magnetic induction heating-assisted synthesis of biodiesel using an alumina/iron oxide nanocatalyst

While generating biodiesel from vegetable oils presents various advantages over fossil fuels, ongoing actions aim to improve the efficiency of this production process. Emphasis is placed on optimizing experimental conditions, including the catalyst selection, reaction media and the energy source for heating and mixing, thereby revealing existing research gaps in biodiesel production. In this sense, we have designed a magnetic nanocatalyst based on iron oxide nanoparticles (IONPs) of 18 nm in diameter incorporated within an alumina matrix of around 500 nm infused with potassium hydroxide that provides the catalyst's mesoporosity and basicity. Magnetization analyses confirmed the superparamagnetic behaviour of the nanocatalyst at room temperature and a saturation magnetisation high enough to ease magnetic recovery for reuse. Additionally, magnetic nanoparticles can serve as nanoheaters when subjected to an alternating magnetic field. The heating efficiency of the isolated IONPs was assessed under various frequency and field conditions, yielding specific absorption rate values of up to 80 W/g. Such heating capacity has allowed the synthesis of fatty acid methyl ester (FAMEs), which constitute the biodiesel at 65 °C under optimal field conditions (100 kHz and 48 kA/m) and ideal reaction parameters: 5 % catalyst, methanol/oil ratio 12:1 and 6 h of reaction, with a conversion of up to 98.6 % determined through NMR characterization of the FAMEs and a 95.6 % yield. FAMEs presence was confirmed by optimizing a swift and efficient FTIR method and their purity by TLC. Overall, the designed nanocatalyst presented for FAME synthesis, which incorporates magnetic separability and effective heating capabilities, holds great promise for cost reduction and process efficiency.

Defect engineering and metal confinement on titanium dioxide enhances SO2/H2O tolerance in NOx reduction: Oxygen and metal vacancies

A desirable catalyst with excellent SO2/H2O tolerance at low temperatures is of great significance for NOx removal from actual flue gas. Defect engineering and metal confinement on metal oxide surfaces have emerged as effective strategies to enhance catalyst selectivity and activity. Herein, a Mn-based catalyst (CeCoMn/TiO2) with metal and oxygen vacancies was constructed by high-energy ball milling. The catalyst exhibited superior SO2/H2O tolerance stability (70.8 %) at 180 ℃ and 40000 h−1 than that prepared by the impregnation method (43.5 %). Metal vacancies can serve as anchor sites to generate well-dispersed active centers, and oxygen vacancies facilitate gas-phase oxygen replenishment and electron transfer. The synergistic effect of metal vacancies and oxygen vacancies improved the activity of the catalyst. In-situ infrared and theoretical calculations reveal that the reaction mechanism follows the Langmuir-Hinshelwood pathway. The catalyst prepared by ball milling has better SO2/H2O tolerance due to stronger acidity and interaction. The synergistic effect of dual-defect found in this study may guide the development of superior anti-poisoning catalysts.