Changes In Binding Energy Research Articles

Sputtering rate of lead, tin and germanium tellurides with low energy argon ions

Sputtering of PbTe, SnTe, and GeTe crystal samples by low-energy Ar+ ions are investigated, and the sputtering rate vsp of the studied compounds, as well as its dependence on both the composition of crystal matrix and the sputtering energy are determined. It is found that under the same conditions the sputtering rate in the sequence of GeTe-SnTe-PbTe telluride compounds increases when their average atomic weight increases. This phenomenon is explained by changes in the surface binding energy of metal atoms in lead, tin and germanium tellurides. It is shown that for all compounds the sputtering rate also increases with the increase in the sputtering energy. In the energy range from 160 to 550 eV,this increase is almost linear. The coefficients of change in the sputtering rate with energy dvsp/dE are calculated. The surface density of Ar+ ion-induced structures and the relative area of the sputtered surface covered by these structures are determined for the natural lateral surfaces of a PbTe crystal grown from melt by the Bridgman method as a function of sputtering energy. It is shown that both studied parameters decrease exponentially with increasing the sputtering energy.

X-ray Photoemission Spectroscopy Study of Uniaxial Magnetic Anisotropy Induced in a Ni Layer Deposited on a LiNbO3 Substrate.

The competition between magnetic shape anisotropy and the induced uniaxial magnetic anisotropy in the heterojunction between a ferromagnetic layer and a ferroelectric substrate serves to control magnetic domain structures as well as magnetization reversal characteristics. The uniaxial magnetic anisotropy, originating from the symmetry breaking effect in the heterojunction, plays a significant role in modifying the characteristics of magnetization dynamics. Magnetoelastic phenomena are known to generate uniaxial magnetic anisotropy; however, the interfacial electronic states that may contribute to the uniaxial magnetic anisotropy have not yet been adequately investigated. Here, we report experimental evidence concerning the binding energy change in the ferromagnetic layer/ferroelectric substrate heterojunction using X-ray photoemission spectroscopy. The binding energy shifts, corresponding to the chemical shifts, reveal the binding states near the interface. Our results shed light on the origin of the uniaxial magnetic anisotropy induced from the heterojunction. This knowledge can provide a means for the simultaneous control of magnetism, mechanics, and electronics in a nano/microsystem consisting of ferromagnetic/ferroelectric materials.

Pt modulates the electronic structure of Pd to improve the performance of Pd-based catalytic combustion catalyst

The electronic modulation between the catalytic active components can improve the catalytic activity and stability of the catalyst. The Pd-based catalysts can easily react with SOX to form stable and inactive sulfates. In this paper, the Pd–Pt-based catalytic combustion catalyst was prepared by replacing part of Pd with a small amount of Pt. The storage tank VOCs catalytic combustion activity and the anti-SO2 poisoning performance of the Pd–Pt-based catalyst and Pd-based catalyst were tested. The Pd 3d binding energy of each Pd-based catalyst was detected by XPS characterization, and the electronic structure changes of Pd active components was analyzed by the change of Pd 3d binding energy. The effect of electrons transfer between Pd and Pt on the improvement of catalytic combustion activity and SO2 poisoning resistance of Pd-based catalysts was analyzed. The results show that the Pt addition can increase the electron cloud density of the Pd active components, and improve the performance of the Pd active components to adsorb and activate oxygen. The reaction of Pd and SOX to form sulfate needs to gain electrons. The increase in the electron cloud density of the Pd active components in Pd–Pt-based catalyst makes it difficult for the Pd active components to adsorb SOX and difficult to react with SOX to form sulfate, thereby preventing the Pd active components from being poisoned and deactivated.

A simple general descriptor for rational design of graphyne-based bifunctional electrocatalysts toward hydrogen evolution and oxygen reduction reactions

The high cost and relative scarcity of platinum (Pt) restrict large-scale commercialization of fuel cells, which has spurred researchers to develop low-cost alternatives integrating with high hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR) catalytic activity. Herein, we performed density functional theory (DFT) calculations to explore the electrocatalytic activity of graphyne nanotubes (GyNTs). Several GyNTs were found to be potential metal-free electrocatalysts, with both HER and ORR activity superior to Pt. Moreover, we revealed a linear relationship between the Gibbs free energy change of O2 adsorption (ΔGOOH) and binding energy of H adsorption (ΔEH), which could be attributed to the fact that both the CO bond of OOH adsorption and the CH bond of H adsorption are single bonds. Therefore, ΔEH is proposed as a general descriptor for the rational design of bifunctional graphyne materials toward HERs and ORRs. Our findings provide a simple strategy for the rational design of bifunctional materials.

Enhanced thermal stability of exciton recombination in CsPbI3 perovskite nanocrystals via zinc alloying

In this work, the Pb2+ substitution with Zn2+ in CsPbI3 perovskite nanocrystals (PNCs) is partially achieved to improve the optoelectronic properties through temperature-pressure assisted crystallization approach. The spectral and dynamic exciton recombination for zinc alloyed CsPbI3 PNCs are probed with steady-state/time-resolved PL (TRPL), transient absorption (TA) techniques. Compared with pure CsPbI3 PNCs, PLQY can be boosted to 60% when incorporating the optimal amount of ZnI2 in the synthesis, and long-term thermal stability are obtained in a series of red-emitting alloyed CsPbI3 PNCs. Simultaneously, the change of exciton binding energy and average optical phonon energy indicate that weaker nonradiative transition for exciton recombination of zinc alloyed CsPbI3 PNCs than those of CsPbI3 PNCs. TRPL and TA spectroscopy are used to understand the photoinduced carrier relaxation processes. The carrier dynamics reveal that the coupling between Zn-induced lowest excited state and exciton trapping state is promoted in zinc alloyed CsPbI3 PNCs, which can significantly enhance the efficiency of excitonic recombination. The improved performance of PLQY and thermal stability makes these zinc alloyed CsPbI3 PNCs as appropriate perovskite materials for efficient optoelectronic devices.

Protease Inhibition Mechanism of Camelid-like Synthetic Human Antibodies.

Macromolecular protease inhibitors and camelid single-domain antibodies achieve their enzymic inhibition functions often through protruded structures that directly interact with catalytic centers of targeted proteases. Inspired by this phenomenon, we constructed synthetic human antibody libraries encoding long CDR-H3s, from which highly selective monoclonal antibodies (mAbs) that inhibit multiple proteases were discovered. To elucidate their molecular mechanisms, we performed in-depth biochemical characterizations on a panel of matrix metalloproteinase (MMP)-14 inhibitory mAbs. Assays included affinity and potency measurements, enzymatic kinetics, a competitive enzyme-linked immunosorbent assay, proteolytic stability, and epitope mapping followed by quantitative analysis of binding energy changes. The results collectively indicated that these mAbs of convex paratopes were competitive inhibitors recognizing the vicinity of the active cleft, with their significant epitopes scattered across the north and south rims of the cleft. Remarkably, identified epitopes were the surface loops that were highly diverse among MMPs and predominately located at the prime side of the proteolytic site, shedding light on the mechanisms of target selectivity and proteolytic resistance. Substrate sequence profiling and paratope mutagenesis further suggested that mAb 3A2 bound to the active-site cleft in a canonical (substrate-like) manner, by direct interactions between 100hNLVATP100m of its CDR-H3 and subsites S1-S5' of MMP-14. Overall, synthetic mAbs carrying convex paratopes can achieve efficient inhibition and thus hold great therapeutic promise for effectively and safely targeting biomedically important proteases.

Using a Heat Diffusion Model to Detect Potential Drug Resistance Genes of Mycobacterium tuberculosis.

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), is one of the oldest known and most dangerous diseases. Although the spread of TB was controlled in the early 20th century using antibiotics and vaccines, TB has again become a threat because of increased drug resistance. There is still a lack of effective treatment regimens for a person who is already infected with multidrug-resistant Mtb (MDR-Mtb) or extensively drug-resistant Mtb (XDRMtb). In the past decades, many research groups have explored the drug resistance profiles of Mtb based on sequence data by GWAS, which identified some mutations that were significantly linked with drug resistance, and attempted to explain the resistance mechanisms. However, they mainly focused on several significant mutations in drug targets (e.g. rpoB, katG). Some genes which are potentially associated with drug resistance may be overlooked by the GWAS analysis. In this article, our motivation is to detect potential drug resistance genes of Mtb using a heat diffusion model. All sequencing data, which contained 127 samples of Mtb, i.e. 34 ethambutol-, 65 isoniazid-, 53 rifampicin- and 45 streptomycin-resistant strains. The raw sequence data were preprocessed using Trimmomatic software and aligned to the Mtb H37Rv reference genome using Bowtie2. From the resulting alignments, SAMtools and VarScan were used to filter sequences and call SNPs. The GWAS was performed by the PLINK package to obtain the significant SNPs, which were mapped to genes. The P-values of genes calculated by GWAS were transferred into a heat vector. The heat vector and the Mtb protein-protein interactions (PPI) derived from the STRING database were inputted into the heat diffusion model to obtain significant subnetworks by HotNet2. Finally, the most significant (P < 0.05) subnetworks associated with different phenotypes were obtained. To verify the change of binding energy between the drug and target before and after mutation, the method of molecular dynamics simulation was performed using the AMBER software. We identified significant subnetworks in rifampicin-resistant samples. Excitingly, we found rpoB and rpoC, which are drug targets of rifampicin. From the protein structure of rpoB, the mutation location was extremely close to the drug binding site, with a distance of only 3.97 Å. Molecular dynamics simulation revealed that the binding energy of rpoB and rifampicin decreased after D435V mutation. To a large extent, this mutation can influence the affinity of drug-target binding. In addition, topA and pyrG were reported to be linked with drug resistance, and might be new TB drug targets. Other genes that have not yet been reported are worth further study. Using a heat diffusion model in combination with GWAS results and protein-protein interactions, the significantly mutated subnetworks in rifampicin-resistant samples were found. The subnetwork not only contained the known targets of rifampicin (rpoB, rpoC), but also included topA and pyrG, which are potentially associated with drug resistance. Together, these results offer deeper insights into drug resistance of Mtb, and provides potential drug targets for finding new antituberculosis drugs.

Electric Field Effect on Excited State Binding Energy and Self-Polarization of a Hydrogenic Impurity in a Spherical Quantum Dot

Effects of the electric field and impurity position on the 2p-excited state self-polarization and binding energy of the electron-impurity in a spherical quantum dot are investigated as a function of the dot radius using variational approach. According to results, turning point of 2p-excited state binding energy changes with the electric field strength and position of impurity in the spherical quantum dot. Self-polarization and binding energy between the 1s-ground state and 2p-excited state of a hydrogenic donor impurity in SQD are presented as a function of the dot radius for different electric field value and impurity positions. Obtained numerical results show a good agreement with the literature.

Evidence of Rotational Fröhlich Coupling in Polaronic Trions.

Electrons commonly couple through Fröhlich interactions with longitudinal optical phonons to form polarons. However, trions possess a finite angular momentum and should therefore couple instead to rotational optical phonons. This creates a polaronic trion whose binding energy is determined by the crystallographic orientation of the lattice. Here, we demonstrate theoretically within the Fröhlich approach and experimentally by photoluminescence emission that the bare trion binding energy (20meV) is significantly enhanced by the phonons at the interface between the two-dimensional semiconductor MoS_{2} and the bulk transition metal oxide SrTiO_{3}. The low-temperature binding energy changes from 60meV in [001]-oriented substrates to 90meV for [111] orientation, as a result of the counterintuitive interplay between the rotational axis of the MoS_{2} trion and that of the SrTiO_{3} phonon mode.

Determination of the pH-dependent immobilization efficacy of α-glycosidase and its catalytic performance on SnO2:Sb/ITO thin films

Non-toxic antimony coated tin oxide (SnO2:Sb/ITO) thin films were prepared to obtain immobilized α-glycosidase (i-α-glycosidase) with better in-vitro activity and storage stability, considering its possible use in future studies on effective anti-diabetic drugs and inhibition. The optimum pH value was determined to be 7.5 via electrostatic surface potential map studies for high activity and immobilization efficiency. An increase in the affinity of α-glycosidase to p-Nitrophenyl-α-glucopyranoside substrate was shown with the change of negative binding energy from -7.1 to -7.3 kcal/mol. The activity values of free-α-glycosidase and i-α-glycosidase were determined at 400 nm by UV–vis spectrophotometric method. The residual activity of i-α-glycosidase after one week was obtained 73.22 % for pH 7.5. The catalytic residues of α-glycosidase were identified as Trp391, Gly566, Asp568, and Trp710 for the best polar contacts with the substrate. The best relative activity and specific activity (U/mg) values at all pH values were obtained in the immobilized enzyme form. High immobilization efficiency was obtained with a value of 85.71 % for pH 7.5. Fourier transform infrared (FTIR) spectrophotometer bandgap values and scanning electron microscopy (SEM) studies proved that α-glycosidase immobilization was successfully performed. As a result, we conclude that SnO2:Sb/ITO thin films could be suitable immobilization materials and therefore may prove beneficial for various biotechnological, pharmacological, and therapeutic applications alike.

Enhancement of catalytic toluene combustion over Pt–Co3O4 catalyst through in-situ metal-organic template conversion

A Pt–Co3O4 catalyst named Pt–Co(OH)2–O was prepared by metal-organic templates (MOTs) conversion and used for catalytic oxidation of toluene. Through the conversion, the morphology of catalysts transformed from rhombic dodecahedron to nanosheet and the coated Pt nanoparticles (NPs) were more exposed. The Binding energy shift in XPS test indicates that the strong metal-support strong interaction (SMSI) has enhanced, and the physicochemical changes caused by it are characterized by other techniques. At the same time, Pt–Co(OH)2–O showed the best catalytic performance (T50 = 157 °C, T90 = 167 °C, Ea = 40.85 kJ mol−1, TOFPt = 2.68 × 10−3 s−1) and good stability. In addition, the in situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) studies have shown that because SMSI weakened the Co–O bond, the introduction of Pt NPs can make the migration of oxygen in the catalyst easier. The change of binding energy change and the content of various species in the quasi in situ XPS experiment further confirmed that the Pt–Co(OH)2–O catalyst has stronger SMSI, resulting in its stronger electron transfer ability and oxygen migration ability, which is conducive to catalytic reactions. This work provides new ideas for the development of supported catalysts and provides a theoretical reference for the relevant verification of SMSI.

Broadband optical properties of monolayer and bulk MoS2

Layered semiconductors such as transition metal dichalcogenides (TMDs) offer endless possibilities for designing modern photonic and optoelectronic components. However, their optical engineering is still a challenging task owing to multiple obstacles, including the absence of a rapid, contactless, and the reliable method to obtain their dielectric function as well as to evaluate in situ the changes in optical constants and exciton binding energies. Here, we present an advanced approach based on ellipsometry measurements for retrieval of dielectric functions and the excitonic properties of both monolayer and bulk TMDs. Using this method, we conduct a detailed study of monolayer MoS2 and its bulk crystal in the broad spectral range (290–3300 nm). In the near- and mid-infrared ranges, both configurations appear to have no optical absorption and possess an extremely high dielectric permittivity making them favorable for lossless subwavelength photonics. In addition, the proposed approach opens a possibility to observe a previously unreported peak in the dielectric function of monolayer MoS2 induced by the use of perylene-3,4,9,10-tetracarboxylic acid tetrapotassium salt (PTAS) seeding promoters for MoS2 synthesis and thus enables its applications in chemical and biological sensing. Therefore, this technique as a whole offers a state-of-the-art metrological tool for next-generation TMD-based devices.

Kinetics of the Thermal Oxidation of Ir(100) toward IrO2 Studied by Ambient-Pressure X-ray Photoelectron Spectroscopy.

Using time-lapsed ambient-pressure X-ray photoelectron spectroscopy, we investigate the thermal oxidation of single-crystalline Ir(100) films toward rutile IrO2(110) in situ. We initially observe the formation of a carbon-free surface covered with a complete monolayer of oxygen, based on the binding energies of the Ir 4f and O 1s core level peaks. During a rather long induction period with nearly constant oxygen coverage, the work function of the surface changes continuously as sensed by the gas phase O 1s signal. The sudden and rapid formation of the IrO2 rutile phase with a thickness above 3 nm, manifested by distinct binding energy changes and substantiated by quantitative XPS analysis, provides direct evidence that the oxide film is formed via an autocatalytic growth mechanism that was previously proposed for PbO and RuO2.

Flexible Fitting of Small Molecules into Electron Microscopy Maps Using Molecular Dynamics Simulations with Neural Network Potentials.

Despite significant advances in resolution, the potential for cryo-electron microscopy (EM) to be used in determining the structures of protein-drug complexes remains unrealized. Determination of accurate structures and coordination of bound ligands necessitates simultaneous fitting of the models into the density envelopes, exhaustive sampling of the ligand geometries, and, most importantly, concomitant rearrangements in the side chains to optimize the binding energy changes. In this article, we present a flexible-fitting pipeline where molecular dynamics flexible fitting (MDFF) is used to refine structures of protein-ligand complexes from 3 to 5 Å electron density data. Enhanced sampling is employed to explore the binding pocket rearrangements. To provide a model that can accurately describe the conformational dynamics of the chemically diverse set of small-molecule drugs inside MDFF, we use QM/MM and neural-network potential (NNP)/MM models of protein-ligand complexes, where the ligand is represented using the QM or NNP model, and the protein is represented using established molecular mechanical force fields (e.g., CHARMM). This pipeline offers structures commensurate to or better than recently submitted high-resolution cryo-EM or X-ray models, even when given medium to low-resolution data as input. The use of the NNPs makes the algorithm more robust to the choice of search models, offering a radius of convergence of 6.5 Å for ligand structure determination. The quality of the predicted structures was also judged by density functional theory calculations of ligand strain energy. This strain potential energy is found to systematically decrease with better fitting to density and improved ligand coordination, indicating correct binding interactions. A computationally inexpensive protocol for computing strain energy is reported as part of the model analysis protocol that monitors both the ligand fit as well as model quality.

Coenzyme Coupling Boosts Charge Transport through Single Bioactive Enzyme Junctions.

SummaryOxidation of formate to CO2 is catalyzed via the donation of electrons from formate dehydrogenase (FDH) to nicotinamide adenine dinucleotide (NAD+), and thus the charge transport characteristics of FDH become essential but remain unexplored. Here, we investigated the charge transport through single-enzyme junctions of FDH using the scanning tunneling microscope break junction technique (STM-BJ). We found that the coupling of NAD+ with FDH boosts the charge transport by ∼2,100%, and the single-enzyme conductance highly correlates with the enzyme activity. The combined flicker noise analysis demonstrated the switching of the coenzyme-mediated charge transport pathway and supported by the significantly reduced HOMO-LUMO gap from calculations. Site-specific mutagenesis analysis demonstrated that FDH-NAD+ stably combined own higher bioactivity and boosts charge transport, and the coupling has been optimized via the natural selection. Our work provides evidence of hydrogen bond coupling in bioactivity but also bridges the charge transport through single-enzyme junctions and enzyme activities.

Evidence for the Dominance of Carrier-Induced Band Gap Renormalization over Biexciton Formation in Cryogenic Ultrafast Experiments on MoS2 Monolayers.

Transition-metal dichalcogenides (TMDs) such as MoS2 display promising electrical and optical properties in the monolayer limit. Due to strong quantum confinement, TMDs provide an ideal environment for exploring excitonic physics using ultrafast spectroscopy. However, the interplay between collective excitation effects on single excitons such as band gap renormalization/exciton binding energy (BGR/EBE) change and multiexciton effects such biexciton formation remains poorly understood. Using two-dimensional electronic spectroscopy, we observe the dominance of single-exciton BGR/EBE signals over optically induced biexciton formation. We make this determination based on a lack of strong PIA features at T = 0 fs in the cryogenic spectra. By means of nodal line slope analysis, we determine that spectral diffusion occurs faster than BGR/EBE change, indicative of distinct processes. These results indicate that at higher sub-Mott limit fluences, collective effects on single excitons dominate biexciton formation.

Effect of cation substituent of dodecanesulfate-based anionic surface active ionic liquids on micellization: Experimental and theoretical studies

Anionic surface active ionic liquid (SAIL), 1-butyl-3-ethoxycarbonylimidazolium dodecanesulfate ([Etbim][C12H25SO4]) was synthesized. The dependence of micellization of dodecanesulfate-based anionic SAILs on cation substituents of anionic SAILs was analyzed using experimental and theoretical studies. Critical micelle concentration of [Etbim][C12H25SO4] was 1.17 mmol/L at 298.15 K. [Etbim][C12H25SO4] showed superior surface property than [Bmim][C12H25SO4] with same dodecanesulfate anion.Theoretical density functional theory (DFT) calculation was used to determine the micellization tendency of anionic SAILs ([Bmim][C12H25SO4] and [Etbim][C12H25SO4]). CMC difference of [Etbim][C12H25SO4] and [Bmim][C12H25SO4] was ascribed to the electrostatic interaction (repulsion or attraction) and hydrophobic interaction of cations ([Bmim]+ and [Etbim]+), dodecanesulfate anion, anionic SAILs ([Bmim][C12H25SO4] or [Etbim][C12H25SO4]), and the interactions toward water molecules in aqueous solution. The hydrocarbon chain lengths of [Bmim]+ and [Etbim]+ reflected the different hydrophobic interaction of cations, which clarified that the important role of cation substituents on micellization of [Etbim][C12H25SO4] and [Bmim][C12H25SO4]. Atomic charge distribution of cations will play important role on the further hydration toward water molecules or electrostatic attraction toward [C12H25SO4]− anion. Typical hydrogen bonds and charge changes of typical atoms were beneficial for electrostatic attraction and electrostatic repulsion between polar groups of SAILs. The electrostatic repulsion and electrostatic attraction between polar groups of SAILs affected the CMC values of [Bmim][C12H25SO4] and [Etbim][C12H25SO4]. Changes of binding energy (D0) and difference of binding energy (ΔD0) confirmed the tendency of [Etbim][C12H25SO4] micelle formation was higher than that of [Bmim][C12H25SO4].

Comparative cation sensing properties of a newly designed urea linked ferrocene-benzimidazole dyad: a DFT study.

Herein, our primary motivation was to elucidate the electronic and physicochemical properties of a novel molecular dyad consisting of ferrocene (Fc; electron donor), urea (u; linker), and amphoteric benzimidazole (BI; electron acceptor) entities. The sensor responses were investigated for various divalent transition metal cations (Mn2+, Fe2+, Co2+, Ni2+, Cu2+, and Zn2+) and the selectivity of this cationophore molecule (Fc-u-BI) to copper ion (Cu2+) was demonstrated by using B3LYP/LANL2DZ method. According to the thermochemical calculations, we justified that Fc-u-BI⋯Cu2+ reached to the lowest binding energy (∆E), enthalpy (∆H), and Gibbs free energy (∆G) changes. In the light of the calculated global descriptors, Fc-u-BI⋯Cu2+ was found to be the softer and thus the most reactive complex. The complex stabilities and their corresponding non-covalent interactions were also investigated by NBO and NCI analyses, respectively. The mechanistic insight into metal cation sensing by the modeled cationophore dyad.

Exfoliation inhibition on aluminum alloy 7075 by water-soluble phthalocyanine derivates in 1 mol/L HCl

The inhibition effects of two phthalocyanine sulfonates on aluminum alloy 7075 were investigated in this study. The gravimetric test showed that the two compounds effectively inhibited the exfoliation corrosion of aluminum alloy 7075 in 1 mol/L hydrochloric acid. The electrochemical test showed the phthalocyanine sulfonates mainly acted as mixed-type inhibitors. The molecular dynamic simulation indicated that the phthalocyanine inhibitors selectively adsorbed on aluminum atoms, which inhibited the dealloying of aluminum from the alloy surface. In XPS analysis, the chemical adsorption between aluminum and phthalocyanine inhibitors was proven by the changes in the electronic binding energy of Al and N.

Structural trends in the dehydrogenation selectivity of palladium alloys.

Alloying is well-known to improve the dehydrogenation selectivity of pure metals, but there remains considerable debate about the structural and electronic features of alloy surfaces that give rise to this behavior. To provide molecular-level insights into these effects, a series of Pd intermetallic alloy catalysts with Zn, Ga, In, Fe and Mn promoter elements was synthesized, and the structures were determined using in situ X-ray absorption spectroscopy (XAS) and synchrotron X-ray diffraction (XRD). The alloys all showed propane dehydrogenation turnover rates 5–8 times higher than monometallic Pd and selectivity to propylene of over 90%. Moreover, among the synthesized alloys, Pd3M alloy structures were less olefin selective than PdM alloys which were, in turn, almost 100% selective to propylene. This selectivity improvement was interpreted by changes in the DFT-calculated binding energies and activation energies for C–C and C–H bond activation, which are ultimately influenced by perturbation of the most stable adsorption site and changes to the d-band density of states. Furthermore, transition state analysis showed that the C–C bond breaking reactions require 4-fold ensemble sites, which are suggested to be required for non-selective, alkane hydrogenolysis reactions. These sites, which are not present on alloys with PdM structures, could be formed in the Pd3M alloy through substitution of one M atom with Pd, and this effect is suggested to be partially responsible for their slightly lower selectivity.