Ir Atoms Research Articles

Controlling the magnetic anisotropy of RumIrn (m + n = 3) clusters using the MgO(001) substrate.

Large perpendicular magnetic anisotropy energy (MAE) and flexible regulation of the magnitude and direction of MAE have great potential for application in information storage devices. Here, utilizing first-principles calculations, we investigated the magnetic properties of free and MgO(001) supported RumIrn clusters (RumIrn@MgO(m + n = 3)). The results indicate that the MAE of mixed clusters increases with the number of Ir atoms due to Ir having a strong coupling between the non-degenerate dxy and dx2-y2 states. The MAE of free Ir3 is -8.18 meV with the easy magnetization direction parallel to the x-axis, while the MAE of supported Ir3 on the MgO substrate increases by a factor of 2.6, and the easy magnetization axis of the structure is shifted to a direction perpendicular to the substrate surface. This change in MAE is due to the significant enhancement in the coupling between the non-degenerate dyz and dx2-y2 states near the Fermi level of Ir3 atoms. Moreover, Ir3@MgO possesses high thermodynamic stability. These results give a new method for manipulating MAE and the direction of easy magnetization, which has great potential for application in magnetic nanodevices.

Oxygen Evolution Electrocatalysis in Acids: Atomic Tuning of the Stability Number for Submonolayer IrOx on Conductive Oxides from Molecular Precursors

Proton-exchange-membrane water electrolyzers (PEMWEs) produce high-purity H2, withstand load fluctuations, and operate with a pure-water feed but require platinum-group-metal catalysts for durability, such as IrO2 and Pt, due to the acidic environment. At the anode, the slow oxygen evolution reaction (OER) requires a high overpotential to achieve relevant current densities (>2 A·cm–2) even with a high loading of IrO2. Using a simple commercial 1,5-cyclooctadiene iridium chloride dimer precursor, we synthesized submonolayer-thick IrOx on the surfaces of conductive metal oxides to make every Ir atom available for catalysis and reach the ultimate lower limit for Ir loading. We show that the reaction on Sb/SnO2 and F/SnO2 conductive oxides is surface-limited and that a continuous Ir–O–Ir network provides improved stability and activity. We cover IrOx with a thin layer of acid-stable TiOx by atomic-layer deposition. The effects of TiOx on the catalyst’s performance were assessed by inductively coupled plasma mass spectrometry (ICP-MS) coupled in situ with an electrochemical flow cell and ex situ by X-ray photoelectron spectroscopy. Tuning the binding environment of IrOx by TiOx addition enhances the intrinsic activity of the active sites, simultaneously accelerating the dissolution of the catalyst and the metal-oxide support. We illustrate the interplay between the support, catalyst, and protection-layer dissolution with OER activity, and highlight the effects of annealing to densify the TiOx protection layer on stability/activity. These ultrathin supported Ir-based catalysts do not eliminate the long-standing issue of the catalyst and support instability during OER in acids, but do provide new insight into the catalyst–support interactions and may also be of utility for advanced spectroscopic investigations of the OER mechanism.

Embedding Group VIII Elements into a 2D Rigid pc-C3N2 Monolayer to Achieve Single-Atom Catalysts with Excellent OER Activity: A DFT Theoretical Study

Under DFT calculations, a systematic investigation is carried out to explore the structures and oxygen evolution reaction (OER) catalytic activities of a series of 2D single-atom catalyst (SAC) systems, which are constructed by doping the transition metal (TM) atoms in group VIII into the cavities of rigid phthalocyanine carbide (pc-C3N2). We can find that when Co, Rh, Ir and Ru atoms are doped in the small or large cavities of a pc-C3N2 monolayer, they can be used as high-activity centers of OER. All these four new TM@C3N2 nanostructures can exhibit very low overpotential values in the range of 0.33~0.48 V, even smaller than the state-of-the-art IrO2 (0.56 V), which indicates considerably high OER catalytic activity. In particular, the Rh@C3N2 system can show the best OER performance, given that doped Rh atoms can uniformly serve as high-OER-active centers, regardless of the size of cavity. In addition, a detailed mechanism analysis was carried out. It is found that in these doped pc-C3N2 systems, the number of outer electrons, the periodic number of doped TM atoms and the size of the embedded cavity can be considered the key factors affecting the OER catalytic activity, and excellent OER catalytic performance can be achieved through their effective cooperation. These fascinating findings can be advantageous for realizing low-cost and high-performance SAC catalysts for OER in the near future.

Adsorption and Oxidation of CO on Co3O4/Ir(100) Thin Films

The combination of noble metals and reducible metal oxides often displays superior catalytic properties in low-temperature CO oxidation reactions. In the present study, we investigated the adsorption and activation of CO on submonolayer and monolayer CoOx films deposited on Ir(100) at low temperature under ultra-high vacuum (UHV) conditions. Using scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), and low energy electron diffraction (LEED), we found that the CoOx films have a (3 × 1) structure and consist of a Co–O bilayer and an O–Co–O trilayer associated with Co2+ and Co3+ states, respectively. A combination of XPS, temperature-programmed desorption (TPD), and infrared reflection absorption spectrum (IRAS) reveals that the presence of the interface of the submonolayer CoOx film and Ir significantly enhances the catalytic activity of cobalt oxide for CO oxidation. In contrast, a monolayer film of CoOx without exposing CoOx–Ir interface sites is hardly active for CO oxidation. CO adsorbs on the bridge sites of Ir atoms on the submonolayer CoOx/Ir(100) surface at 100 K. Upon heating, CO partially reacts with oxygen on the surface to produce CO2, which desorbs at 215 K, while unreacted CO molecules adsorbed on Ir bridge sites migrate to top sites. Increasing the temperature leads to CO2 desorption at 295 and 325 K, arising from the reaction of CO with chemisorbed oxygen on the Ir surface and oxygen of cobalt oxide, respectively. These results reveal the importance of the interface between Ir and cobalt oxide in the oxidation of CO.

Electronic Properties of Pyrochlore-Type Ca2Ir2O7

The electrical resistivity, magnetic susceptibility, and heat capacity of sintered samples of Ca2Ir2O7, in which pentavalent Ir atoms with 5d4 electron configuration form a pyrochlore structure, have been studied. The obtained experimental data strongly suggest that Ca2Ir2O7 is metallic below room temperature and exhibits no electronic or magnetic phase transitions above 0.12 K.

Activity Enhancement of PtIr Catalysts for Complete Ethanol Oxidation Reaction by Tuning C–O Coupling Abilities

Designing efficient catalysts for the complete ethanol oxidation reaction (EOR) remains challenging because of its complex reaction network, which involves more than 70 reactions of C2 species, many reactions of C1 species, water dissociation, as well as reactions leading to by-products. Recently, the promising EOR performance of the one-atom-thick Ir-rich skin of a bimetallic PtIr electrocatalyst was illustrated and its further improvement requires a thorough understanding of the complete EOR mechanism that is still largely lacking. Therefore, we studied 58 critical elementary reactions of complete EOR including all three stages of catalysis of ethanol oxidation, i.e., dehydrogenation, C–C bond cleavage, and CO2 formation, as well as including water dissociation, on three (100)-exposed layered bimetallic Pt–Ir catalysts using density functional theory (DFT) calculations. Based on the activation and reaction energies, we mapped out the mechanisms of complete EOR on these layered PtIr catalysts. The DFT results demonstrated that the different C–O coupling abilities of the catalyst plays a leading role in the complete EOR performance of Pt–Ir catalysts. We further performed DFT studies on the reactions on a Ir@Pt(100) surface with about 6% Pt atoms on the Ir layer. The surface Pt atoms exhibit excellent C–O coupling of C1 species (e.g., CO + O → CO2), while the Ir atoms prevent the C–OH coupling to form CH3COOH (CH3CO + OH → CH3COOH). Both DFT and kinetics studies indicate that the Ir@Pt(100) surface with Pt-doped active sites is the best for complete EOR and is responsible for the experimentally observed high catalytic performance. This work indicates effective EOR catalysis need to go beyond single metal catalysts and the core–shell structures of multimetallic catalysts.

Iridium single atoms incorporated in Co3O4 efficiently catalyze the oxygen evolution in acidic conditions

Designing active and stable electrocatalysts with economic efficiency for acidic oxygen evolution reaction is essential for developing proton exchange membrane water electrolyzers. Herein, we report on a cobalt oxide incorporated with iridium single atoms (Ir-Co3O4), prepared by a mechanochemical approach. Operando X-ray absorption spectroscopy reveals that Ir atoms are partially oxidized to active Ir>4+ during the reaction, meanwhile Ir and Co atoms with their bridged electrophilic O ligands acting as active sites, are jointly responsible for the enhanced performance. Theoretical calculations further disclose the isolated Ir atoms can effectively boost the electronic conductivity and optimize the energy barrier. As a result, Ir-Co3O4 exhibits significantly higher mass activity and turnover frequency than those of benchmark IrO2 in acidic conditions. Moreover, the catalyst preparation can be easily scaled up to gram-level per batch. The present approach highlights the concept of constructing single noble metal atoms incorporated cost-effective metal oxides catalysts for practical applications.

Superconducting properties of the C15-type Laves phase ZrIr2 with an Ir-based kagome lattice

We report systematic studies on superconducting properties of the Laves phase superconductor ZrIr2. It crystallizes in a C15-type (cubic MgCu2-type, space group ) structure in which the Ir atoms form a kagome lattice, with cell parameters a = b = c = 7.3596(1) Å. Resistivity and magnetic susceptibility measurements indicate that ZrIr2 is a type-II superconductor with a transition temperature of 4.0 K. The estimated lower and upper critical fields are 12.8 mT and 4.78 T, respectively. Heat capacity measurements confirm the bulk superconductivity in ZrIr2. ZrIr2 is found to possibly host strong-coupled s-wave superconductivity with the normalized specific heat change ΔC e/γ T c ∼ 1.86 and the coupling strength Δ0/k B T c ∼ 1.92. First-principles calculations suggest that ZrIr2 has three-dimensional Fermi surfaces with simple topologies, and the states at Fermi level mainly originate from the Ir-5d and Zr-4d orbitals. Similar to SrIr2 and ThIr2, spin–orbit coupling has dramatic influences on the band structure in ZrIr2.

Kinetic Acceleration of Lithium Polysulfide Conversion via a Copper-Iridium Alloying Catalytic Strategy in Li-S Batteries.

To solve the shuttle effect of soluble lithium polysulfides (LiPSs), a porous N-doped carbon-supported copper-iridium alloy catalyst composite (CuIr/NC) has been synthesized and served as a modified cathode sulfur host for lithium-sulfur batteries (LSBs). The metal-organic framework-derived calcined carbon frameworks build efficient conductive channels for fast ion/electron transport. Furthermore, alloying noble metals Ir with thiophilic metal Cu provides abundant active sites to effectively capture LiPSs and accelerate the catalytic conversion process, originating from modulating the surface electronic structure of the metal Cu by introducing Ir atoms to affect the 3d-orbital distribution. All of the above are strongly supported by a range of characterization studies and density functional theory calculations. Benefiting from the above advantages, the LSBs generally show satisfactory cycling performance. Apart from exhibiting a terrific initial specific capacity of 1288 mA h g-1 at 0.2 C, they can also keep long-term cycling stability under a high current density up to 5 C together with a slow specific capacity decay ratio (0.033%) per cycle after 1000 cycles. In addition, it is worth mentioning that a high areal capacity (4.7 mA h cm-2) with a low E/S ratio (6.2 μL mg-1) could still be accomplished at higher sulfur loading (4.3 mg cm-2).

Construction of Ordered Atomic Donor–Acceptor Architectures in bcc IrGa Intermetallic Compounds toward Highly Electroactive and Stable Overall Water Splitting

AbstractBenefiting from ordered atomic structures and strong d‐orbital interactions, intermetallic compounds (IMCs) are promising electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, the body‐centered cubic IrGa IMCs with atomic donor–acceptor architectures are synthesized and anchored on the nitrogen‐doped reduced graphene oxide (i.e., IrGa/N‐rGO). Structural characterizations and theoretical calculations reveal that the electron‐rich Ir sites are atomically dispersed in IrGa/N‐rGO, facilitating the electron transfer between Ir atoms and adsorbed species, which can efficiently decrease the energy barriers of the potential determining step for both HER and OER. Impressively, the IrGa/N‐rGO||IrGa/N‐rGO exhibits excellent performance for overall water splitting in alkaline medium, requiring a low cell voltage of 1.51 V to achieve 10 mA cm−2, meanwhile, exhibiting no significant degradation for 100 h. This work demonstrates that the rational design of noble metal electrocatalysts with donor–acceptor architectures is beneficial for catalytic reactions in energy conversion applications.

Weakening s-d orbital hybridization of metallic iridium by tungsten atoms for acidic water splitting

To economically realize proton electrolyte membrane water splitting technology, stable and high-performance oxygen evolution reaction (OER) electrocatalyst is significantly demanded. In this work, we invite tungsten atoms to metallic iridium (Ir) to weaken s-d hybridization of Ir-Ir bond due to the higher electronegativity accepting electron from Ir atoms; as a result, the adsorbed O* species become electrophilic favorable for the nucleophilic attack by H2O leading to 22 % decrement in energy barrier for the formation of OOH* species. Therefore, iridium-tungsten (IrW) electrocatalyst exhibits 3.7-fold higher turnover frequency (TOF) than metallic Ir at overpotential of 370 mV in acidic OER catalysis. Moreover, stable OER performance is recorded due to the high cohesive energy of tungsten atoms. Additionally, TOF of IrW electrocatalyst reaches 10.1 s−1 at overpotential of 100 mV in acidic hydrogen evolution reaction (HER) test, 7.6-time higher than Pt/C and metallic Ir. IrW electrocatalyst only needs 1.52 V to attain 10 mA cm−2 in acidic overall water splitting.

Isolating Contiguous Ir Atoms and Forming Ir-W Intermetallics with Negatively Charged Ir for Efficient NO Reduction by CO.

The lack of efficient catalysts with a wide working temperature window and vital O2 and SO2 resistance for selective catalytic reduction of NO by CO (CO-SCR) largely hinders its implementation. Here, a novel Ir-based catalyst with only 1wt% Ir loading is reported for efficient CO-SCR. In this catalyst, contiguous Ir atoms are isolated into single atoms, and Ir-W intermetallic nanoparticles are formed, which are supported on ordered mesoporous SiO2 (KIT-6). Notably, this catalyst enables complete NO conversion to N2 at 250°C in the presence of 1% O2 and has a wide temperature window (250-400°C), outperforming the comparison samples with Ir isolated-single-atomic-sites and Ir nanoparticles, respectively. Also, it possesses a high SO2 tolerance. Both experimental results and theoretical calculations reveal that single Ir atoms are negatively charged, dramatically enhancing the NO dissociation, while the Ir-W intermetallic nanoparticles accelerate the reduction of the N2 O and NO2 intermediates by CO.

Activated Ni-O-Ir Enhanced Electron Transfer for Boosting Oxygen Evolution Reaction Activity of LaNi1-x Irx O3.

Tuning the structure of the active center of catalysts to atomic level provides the most efficient utilization of the active component, which plays an especially important role for precious metals. In this study, the liquid phase ion exchange method is used to introduce atomic Ir into LaNiO3 perovskite oxide, which shows excellent catalytic performance in the oxygen evolution reaction (OER). The catalyst, LaNi0.96 Ir0.04 O3 , with the optimal concentration of Ir, displays an overpotential of just 280mV at 10mAcm-2 . The introduced Ir enriches the surface electron density significantly, which not only improves site-to-site electron transfer between O and Ni sites but also allows stable adsorption of the intermediates. Theresults of cyclic voltammetry tests reveal the superior overpotential and remarkable efficiency of the OER process because of the strong interactions in Ni-O-Ir. Moreover, the Ir atom inhibits the participation of a lattice oxygen oxidation mechanism (LOM) in LaNiO3 that guarantees the stability of the catalyst in alkaline conditions. It is anticipated that this work will be instrumental for the preparation and study of a broad range of atomic metal-doped perovskite oxides for water splitting.

Theoretical study of transition metal atom pairs anchored in g-CN monolayers for ammonia decomposition

One way to efficiently store, transport, and utilize hydrogen is to convert it into liquid ammonia (NH3). Exploring low-cost and high-efficiency electrocatalysts for liquid ammonia oxidation reaction (AOR) is critical in developing hydrogen production fuel cells. Here, we have investigated the catalytic electro-oxidation of liquid ammonia on surfaces of transition metal dimer anchored in g-CN (TM2@g-CN) monolayer to derive insights into the reaction mechanism and evaluate the catalystic activity. Our results show that the mechanism proposed by Gerischer and Mauerer is kinetically preferred. Furthermore, Fe2, Co2, Ru2, Rh2, and Ir2 anchored in g-CN monolayer exhibit high AOR catalytic activity. In particular, Rh and Ir atoms exhibit excellent performance for hydrogen evolution reaction (HER), indicating that they can be used as the efficient bifunctional catalysts towards ammonia splitting for production H2. Remarkably, by regulating TM atoms with different d-electron numbers, the d-band center (εd) of TM atoms on TM2@g-CN can be turned and utilized to predict AOR performance, which provides a theoretical guideline for the design of advanced AOR electrocatalysts.

The Carbon Corrosion Resistance of Mesoporous PtIr Catalysts in Proton Exchange Membrane Fuel Cells

AbstractAs the main degradation mechanism, carbon corrosion behavior plays an important role to deteriorate the durability and lifetime of PEMFCs. For addressing the issue, we synthesized a novel type of mesoporous PtIr alloy catalyst through the self‐assembled composite micelles made of PS‐b‐P2VP‐b‐PEO triblock copolymer and metal acid ions (PtCl62− and IrCl62−). The strength of large ECSA and high limited current density on PtIr85 : 15 and PtIr75 : 25 catalysts could be attributed to the uniformly ordered mesoporous structure. It is beneficial to the sufficient exposure of reactive sites and the diffusion of reactants and products. The corresponding PtIr/C alloy catalysts were obtained to deposit PtIr alloys on Vulcan XC 72R. After stress cycling, the increase rate of double‐layer capacitance is the slowest on PtIr75 : 25/C and keeps the minimum values. Moreover, the increase speed of Q/HQ peak is also associated with the increased Ir content in catalyst. Here, incorporation with Ir atom has been proved as an effective method to protect the carbon corrosion behaviors.

Construction of hierarchical and self-supported NiFe-Pt3Ir electrode for hydrogen production with industrial current density

Rational design and fabrication of electrocatalysts from the perspective of mass transfer and electronic structure is highly desirable for hydrogen evolution reaction (HER). Herein, a hierarchical and self-supported electrode comprising Cu nanowires, NiFe nanosheets, and Pt3Ir alloy nanoparticles (Cu NWs@NiFe-Pt3Ir) was in situ constructed and established as a highly active and robust electrocatalyst for HER with industrial current densities. Benefiting from the hierarchical structure, abundant active sites, and positive electronic interaction between NiFe and Pt3Ir, the Cu NWs@NiFe-Pt3Ir electrode shows extremely low overpotentials of 210 and 239 mV to reach industrial current densities of 500 and 1000 mA cm−2 in 1.0 M KOH solution, respectively. More importantly, Cu NWs@NiFe-Pt3Ir electrode shows robust durability with a slight increment of 8 mV for the required potential after consecutive tests for 7 days under 500 mA cm−2. As further revealed by electrochemical and theoretical studies, the reaction kinetics of NiFe is greatly promoted by coupling with Pt3Ir, and the d-band center energy level of Pt 5d orbital is lowered by Ir atom, which not only facilitates the electron consumption at the electrode/electrolyte interface but also optimizes the energies for H adsorption and H2 desorption. This work provides valuable insights into the construction of self-supported electrodes with extraordinary activity and durability for industrial applications.

Determination and localization of specific proteins in individual ARPE-19 cells by single cell and laser ablation ICP-MS using iridium nanoclusters as label

Single cell-inductively coupled plasma-mass spectrometry (sc-ICP-MS) and laser ablation (LA)-ICP-MS have been complementary employed to develop a comprehensive study of APOE and claudin-1 expression in ARPE-19 cells submitted to a glucose treatment (100 mM, 48 h) that induces oxidative stress conditions. Results were compared with control cells. The determination of the two proteins by ICP-MS was sequentially carried out using specific immunoprobes labelled with IrNCs that offer a huge amplification (1760 ± 90 atoms of Ir on average). A novel sample introduction system, the microFAST Single Cell set-up, was employed for sc-ICP-MS analysis. This introduction system resulted in a cellular transport efficiency of 85 ± 9% for ARPE-19 cells (91 ± 5% using a PtNPs standard). After the proper immunocytochemistry protocol with the specific IrNCs immunoprobes in cell suspensions (sc-ICP-MS), the mass of APOE and claudin-1 in individual ARPE-19 cells was obtained. Average detection limits per cell by sc-ICP-MS were 0.02 fg of APOE and 3 ag of claudin-1. The results of sample analyses obtained by sc-ICP-MS were validated with commercial ELISA kits. The distribution of both target proteins in individual cells (fixated in the chamber wall) was unveiled by LA-ICP-MS. The high amplification provided by the IrNCs immunoprobes allowed the identification of APOE and claudin-1 within individual ARPE-19 cells. High resolution images were obtained using a laser spot of 2 × 2 μm.

Single-Site Heterogeneous Organometallic Ir Catalysts Embedded on Graphdiyne: Structural Manipulation Beyond the Carbon Support.

Accurate control over the coordination circumstances of single-atom catalysts (SACs) is decisive to their intrinsic activity. Here, two single-site heterogeneous organometallic catalysts (SHOCs), Cp*Ir-L/GDY (L = OH- and Cl- ; Cp* = pentamethylcyclopentadienyl), with the fine-tuned local coordination and electronic structure of Ir sites, are constructed by anchoring Cp*Ir complexes on graphdiyne (GDY) matrix via a one-pot procedure. The spectroscopic studies and theoretical calculations indicate that the Ir atoms in Cp*Ir-Cl/GDY and Cp*Ir-OH/GDY have a much higher oxidation state than Ir in the SAC Ir/GDY. As a proof-of-principle demonstration, the GDY-supported SHOCs are used for formic acid dehydrogenation, which display a fivefold enhancement of catalytic activity compared with SAC Ir/GDY. The kinetic isotope effect and in situ Fourier-transform infrared studies reveal that the rate-limiting step is the β-hydride elimination process, and Cp* on the Ir site accelerates the β-hydride elimination reaction. The GDY-supported SHOCs integrate the merits of both SACs and molecular catalysts, wherein the isolated Ir anchored on GDY echoes with SACs' behavior, and the Cp* ligand enables precise structural and electronic regulation like molecular catalysts. The scheme of SHOCs adds a degree of freedom in accurate regulation of the local structure, the electronic property, and therefore the catalytic performance of single-atom catalysts.

Role of bimetallic Au-Ir subnanometer clusters mediating O2 adsorption and dissociation on anatase TiO2 (101).

A comprehensive computational study on the oxygen molecule (O2) adsorption and activation on bimetallic Au-Ir subnanometer clusters supported on TiO2(101)- up to five atoms in size-is performed. A global optimization density functional theory-based basin-hopping algorithm is used to determine putative global minima configurations of both mono- and bimetallic clusters supported on the metal oxide surface for all sizes and compositions. Our results indicate a strong cluster-oxide interaction for monometallic Ir clusters with calculated adsorption energy (Eads) values ranging from -3.11 to -5.91eV. Similar values are calculated for bimetallic Au-Ir clusters (-3.21 up to -5.69eV). However, weaker Eads values are calculated for Au clusters (ranging from -0.66 to -2.07eV). As a general trend, we demonstrate that for supported Au-Ir clusters on TiO2(101), those Ir atoms preferentially occupy cluster-oxide interface positions while acting as anchor sites for the Au atoms. The overall geometric arrangements of the putative global minima configurations define O2 adsorption and dissociation, particularly involving the monometallic Au5 and Ir5 as well as the bimetallic Au2Ir3 and Au3Ir2 supported clusters. Spontaneous O2 dissociation is observed on both Ir5 and on the Ir-metallic part of Au3Ir2 and Au2Ir3 supported clusters. This is in sharp contrast with supported Au5, where a large activation energy is needed (1.90eV). Interestingly, for Au5, we observe that molecular O2 adsorption is favorable at the cluster/oxide interface, followed by a smaller dissociation barrier (0.71eV). From a single cluster catalysis point of view, our results have strong implications in the ongoing understanding of oxide supported bimetallic while providing a useful first insight into the continuous in silico design of novel subnanometer catalysts.

A two-step optimization approach for structures investigation of Pd-Ir bimetallic nanoclusters

The structures of nanoalloys are crucial for understanding their catalytic performance because the stable structures can affect the activity and selectivity of nanocatalysts. Therefore, investigating the stable structures of nanoalloys is important to understand their catalytic activities. In this article, a two-step optimization approach by combining a basin hoping genetic algorithm (BHGA) and DFT calculation is employed to investigate the structural stability of Pd-Ir alloy nanoclusters. Different compositions (Pd and Ir atoms proportion) and different initial configurations of 38-atom Pd-Ir alloys are considered. The combination of BHGA and DFT method can effectively find the stable structures of truncated octahedral (TO) configurations for 38-atom Pd-Ir alloys with high accuracy and low time complexity. Furthermore, the formation energy and bond energy of Pd-Ir clusters are calculated and analyzed, the results show the bond strength follows Pd-Pd > Pd-Ir > Ir-Ir. The most stable configuration is Pd6Ir32 with all the core sites are occupied by Pd, which shows better electrochemical performance.