A Cu/Pt Near-Surface Alloy for Water−Gas Shift Catalysis

Water dissociation and COOH formation on Fe modified Cu(100) surface: A density functional theory study

Water splitting has emerged as a promising route for sustainable hydrogen production. In this research paper, adsorption and dissociation of H2O accompanied with dissociated constituents reactions with CO2 and CO have been investigated on Fe modified Cu(100) surface employing density functional theory (DFT) at GGA-PW91 level. The adsorption and other reactions carried out on Fe2-Cu(100) surfaces gave very promising results. The adsorption of H2O on Fe top of this surface occurs yielding Eads -1.73 eV, which highlights a favorable adsorption on the Fe-modified Cu(100) surface. The activation energy for the water splitting reaction is found to be 0.65 eV, suggesting a feasible pathway for hydrogen evolution. The process also accompanies reaction energy of -0.54 eV. Furthermore, the interaction between carbon dioxide (CO2) and the H-atom on the surface lead to the formation of COOH through surmounting an activation barrier of 1.09 eV. The final position of COOH gets further stabilization having exothermicity of -0.43 eV. Another route for COOH formation from CO + OH operates on the Cu(100) part of the surface with a small activation barrier of 0.14 eV through exothermic process of -0.29 eV, however, diffusion of CO and OH from Fe to Cu is energetically expensive. This study signifies the consumption of CO and CO2 in addition to water splitting giving birth to useful products.

Theoretical Calculations on Metal Catalysts Toward Water-Gas Shift Reaction: a Review

Water-gas shift (WGS) reaction offers a dominating path to hydrogen generation from fossil fuel, in which heterogeneous metal catalysts play a crucial part in this course. This review highlights and summarizes recent developments on theoretical calculations of metal catalysts developed to date, including surface structure (e. g., monometallic and polymetallic systems) and interface structure (e. g., supported catalysts and metal oxide composites), with special emphasis on the characteristics of crystal-face effect, alloying strategy, and metal-support interaction. A systematic summarization on reaction mechanism was performed, including redox mechanism, associative mechanism as well as hybrid mechanism; the development on chemical kinetics (e. g., molecular dynamics, kinetic Monte Carlo and microkinetic simulation) was then introduced. At the end, challenges associated with theoretical calculations on metal catalysts toward WGS reaction are discussed and some perspectives on the future advance of this field are provided.

Elucidation of Cu-Zn Surface Alloying on Cu(997) by Machine-Learning Molecular Dynamics

The Cu-Zn surface alloy has been extensively involved in the investigation of the true active site of Cu/ZnO/Al2O3, the industrial catalyst for methanol synthesis which remains under controversy. The challenge lies in capturing the interplay between the surface and reaction under operating conditions, which can be overcome given that the explicit dynamics of the system is known. To provide a better understanding of the dynamic of Cu-Zn surface at the atomic level, the structure and the formation process of the Cu-Zn surface alloy on Cu(997) were investigated by machine-learning molecular dynamics (MD). Gaussian process regression aided with on-the-fly learning was employed to build the force field used in the MD. The simulation reveals atomistic details of the alloying process, that is, the incorporation of deposited Zn adatoms to the Cu substrate. The surface alloying is found to start at upper and lower terraces near the step edge, which emphasize the role of steps and kinks in the alloying. The incorporation of Zn at the middle terrace was found at the later stage of the simulation. The rationalization of alloying behavior was performed based on statistics and barriers of various elementary events that occur during the simulation. It was observed that the alloying scheme at the upper terrace is dominated by the confinement of Zn step adatoms by other adatoms, highlighting the importance of step fluctuations in the alloying process. On the other hand, the alloying scheme at the lower terrace is dominated by direct exchange between the Zn step adatom and the Cu atom underneath. The alloying at the middle terrace is dominated by the wave deposition mechanism and deep confinement of Zn adatoms. The short propagation of alloyed Zn in the middle terrace was observed to proceed by means of indirect exchange instead of local exchange as proposed in the previous scanning tunneling microscopy (STM) observation. The comparison of migration rate and activation energies to the result of STM observation is also made. We have found that at a certain distance from the surface, the STM tip significantly affects the elementary events such as vacancy formation and direct exchange.

CO Oxidation over Alumina-Supported Copper Catalysts

CO oxidation, one of the most important chemical reactions, has been commonly studied in both academia and the industry. It is one good probe reaction in the fields of surface science and heterogeneous catalysis, by which we can gain a better understanding and knowledge of the reaction mechanism. Herein, we studied the oxidation state of the Cu species to seek insight into the role of the copper species in the reaction activity. The catalysts were characterized by XRD, N2 adsorption-desorption, X-ray absorption spectroscopy, and temperature-programmed reduction. The obtained results suggested that adding of Fe into the Cu/Al2O3 catalyst can greatly shift the light-off curve of the CO conversion to a much lower temperature, which means the activity was significantly improved by the Fe promoter. From the transient and temperature-programmed reduction experiments, we conclude that oxygen vacancy plays an important role in influencing CO oxidation activity. Adding Fe into the Cu/Al2O3 catalyst can remove part of the oxygen from the Cu species and form more oxygen vacancy. These oxygen vacancy sites are the main active sites for CO oxidation reaction and follow a Mars-van Krevelen-type reaction mechanism.

Towards the rational design of Pt-based alloy catalysts for the low-temperature water-gas shift reaction: from extended surfaces to single atom alloys

The rational design of Pt-based catalysts for the low-temperature water-gas-shift (LT-WGS) reaction is an active research field because of its important role played in the fuel cell-based hydrogen economy, especially in mobile applications. Previous theoretical analyses have suggested that Pt alloys, leading to a weaker CO binding affinity than the Pt metal, could help alleviate CO poisoning and thus should be promising catalysts of the LT-WGS reaction. However, experimental research along this line was rather ineffective in the past decade. In the present work, we employed the state-of-the-art kinetic Monte Carlo (KMC) simulations to examine the influences of the electronic effect by introducing sub-surface alloys and/or core–shell structures, and the synergetic effect by introducing single atom alloys on the catalytic performance of Pt-alloy catalysts. Our KMC simulations have highlighted the importance of the OH binding affinity on the catalyst surfaces to reduce the barrier of water dissociation as the rate determining step, instead of the CO binding affinity as has been emphasized before in conventional mean-field kinetic models. Along this new direction of catalyst design, we found that Pt–Ru synergetic effects can significantly increase the activity of the Pt metal, leading to Ru_1–3@Pt alloys with a tetrahedron site of one surface-three subsurface Ru atoms on the Pt host, showing a turnover frequency of about five orders of magnitude higher than the Pt metal.

KMC simulations show that decreasing the barrier of H₂O decomposition is more beneficial than decreasing the CO binding affinity in LT-WGS, while the latter was overemphasized by MF-MKM. Here Ru_1–3@Pt alloy is proposed as a promising catalyst.

Nanoengineering of Catalysts for Enhanced Hydrogen Production

Hydrogen (H2) has emerged as a sustainable energy carrier capable of replacing/complementing the global carbon-based energy matrix. Although studies in this area have often focused on the fundamental understanding of catalytic processes and the demonstration of their activities towards different strategies, much effort is still needed to develop high-performance technologies and advanced materials to accomplish widespread utilization. The main goal of this review is to discuss the recent contributions in the H2 production field by employing nanomaterials with well-defined and controllable physicochemical features. Nanoengineering approaches at the sub-nano or atomic scale are especially interesting, as they allow us to unravel how activity varies as a function of these parameters (shape, size, composition, structure, electronic, and support interaction) and obtain insights into structure–performance relationships in the field of H2 production, allowing not only the optimization of performances but also enabling the rational design of nanocatalysts with desired activities and selectivity for H2 production. Herein, we start with a brief description of preparing such materials, emphasizing the importance of accomplishing the physicochemical control of nanostructures. The review finally culminates in the leading technologies for H2 production, identifying the promising applications of controlled nanomaterials.

Interplaying coordination and ligand effects to break or make adsorption-energy scaling relations

The linear relations between adsorption energies are one of the cornerstones of contemporary catalysis in view of the simplicity and predictive power of the computational models built upon them. Despite their extensive use, the exact nature of scaling relations is not yet fully understood, and a comprehensive theory of scaling relations is yet to be elaborated. So far, it is known that scalability is dictated by the degree of resemblance of the adsorbed species. In this work, density functional theory calculations show that CO and OH, two dissimilar species, scale or not depending on the surface facet where they adsorb at Pt alloys. This peculiar behavior arises from an interplay of ligand and geometric effects that can be used to modulate adsorption-energy scalability. This study opens new possibilities in catalysis, as it shows that surface coordination is a versatile tool to either balance or unbalance the similarities among adsorbates at alloy surfaces.

Application of Optimization Algorithms in Clusters

The structural characterization of clusters or nanoparticles is essential to rationalize their size and composition-dependent properties. As experiments alone could not provide complete picture of cluster structures, so independent theoretical investigations are needed to find out a detail description of the geometric arrangement and corresponding properties of the clusters. The potential energy surfaces (PES) are explored to find several minima with an ultimate goal of locating the global minima (GM) for the clusters. Optimization algorithms, such as genetic algorithm (GA), basin hopping method and its variants, self-consistent basin-to-deformed-basin mapping, heuristic algorithm combined with the surface and interior operators (HA-SIO), fast annealing evolutionary algorithm (FAEA), random tunneling algorithm (RTA), and dynamic lattice searching (DLS) have been developed to solve the geometrical isomers in pure elemental clusters. Various model or empirical potentials (EPs) as Lennard-Jones (LJ), Born-Mayer, Gupta, Sutton-Chen, and Murrell-Mottram potentials are used to describe the bonding in different type of clusters. Due to existence of a large number of homotops in nanoalloys, genetic algorithm, basin-hopping algorithm, modified adaptive immune optimization algorithm (AIOA), evolutionary algorithm (EA), kick method and Knowledge Led Master Code (KLMC) are also used. In this review the optimization algorithms, computational techniques and accuracy of results obtained by using these mechanisms for different types of clusters will be discussed.

Methane activation on single-atom Ir-doped metal nanoparticles from first principles

The breaking of the C-H bond of CH4 is of great importance, and one of the most efficient strategies in heterogeneous catalysis is to alter the electronic structure of a surface by doping it with different metal elements or controlling the stoichiometry. We present an in-depth study on methane activation on pure metal and single-atom Ir-doped alloy nanoparticles, which are constructed based on (100), (110), (111) surfaces using density functional theory (DFT) calculations. DFT results show that the dissociation barriers of CH4 on the Ir-doped alloy surfaces are about 0.3-0.4 eV, much lower than those on the pure metal surfaces (i.e., 0.6-0.8 eV). DFT-based transition state theory further reveals the rates of the first C-H activation on single-atom Ir-doped alloy nanoparticles at the early stages. Importantly, a strong temperature dependence is mainly contributed by the proportion of the exposed (110) surface. The Ir-doped Pt nanoparticle is found to be an efficient catalyst for methane activation in potential industrial applications. These important results are helpful for further designing new metal catalysts for methane activation at the atomic/molecular level.

Dynamic Restructuring Induced Oxygen Activation on AgCu Near-Surface Alloys

Recent studies have shown that the addition of Cu to Ag catalysts improves their epoxidation performance by increasing the overall selectivity of the bimetallic catalyst. We have prepared AgCu near-surface alloys and used scanning tunneling microscopy to gain an atomistic picture of O₂ dissociation on the bimetallic system. These data reveal a higher dissociative sticking probability for O₂ on AgCu than on Ag(111), and density functional theory (DFT) confirms that the O₂ dissociation barrier is 0.17 eV lower on the alloy. Surprisingly, we find that, after a slow initial uptake of O₂, the sticking probability increases exponentially. Further DFT calculations indicate that surface oxygen reverses the segregation energy for AgCu, stabilizing Cu atoms in the Ag layer. These single Cu atoms in the Ag surface are found to significantly lower the O₂ dissociation barrier. Together, these results explain nonlinear effects in the activation of O₂ on this catalytically relevant surface alloy.

Reduced SrTiO3-supported Pt-Cu alloy nanoparticles for preferential oxidation of CO in excess hydrogen

Activity and long-term stability of oxide-metal heterostructure catalysts can be engineered through tuning the oxygen storage capacity (OSC) of the support and careful control of the composition of the supported metal nanoparticle. In this work, we probe these two factors for microwave-synthesized PtCu alloy nanoparticles supported on reduced-SrTiO3. The heterostructures are tested for their activity towards preferential CO oxidation in the presence of H2 at typical operating temperatures used for polymer electrolyte membrane fuel cells (PEMFCs). Through controlled temperature programmed reduction/temperature programmed oxidation (TPR/TPO) experiments, we show that the OSC of the support can be enhanced through heavy surface reduction of SrTiO3. Adsorption-desorption experiments establish the strikingly different CO adsorption behavior over monometallic Pt and PtCu alloy nanoparticles. Through detailed catalytic studies, we establish a trend in the selectivity and stability of CO conversions over the PtCu alloy catalysts that can indeed be tuned by varying the PtCu composition in a facile microwave synthesis.

Recent Progress with In Situ Characterization of Interfacial Structures under a Solid-Gas Atmosphere by HP-STM and AP-XPS

: Surface science is an interdisciplinary field involving various subjects such as physics, chemistry, materials, biology and so on, and it plays an increasingly momentous role in both fundamental research and industrial applications. Despite the encouraging progress in characterizing surface/interface nanostructures with atomic and orbital precision under ultra-high-vacuum (UHV) conditions, investigating in situ reactions/processes occurring at the surface/interface under operando conditions becomes a crucial challenge in the field of surface catalysis and surface electrochemistry. Promoted by such pressing demands, high-pressure scanning tunneling microscopy (HP-STM) and ambient pressure X-ray photoelectron spectroscopy (AP-XPS), for example, have been designed to conduct measurements under operando conditions on the basis of conventional scanning tunneling microscopy (STM) and photoemission spectroscopy, which are proving to become powerful techniques to study various heterogeneous catalytic reactions on the surface. This report reviews the development of HP-STM and AP-XPS facilities and the application of HP-STM and AP-XPS on fine investigations of heterogeneous catalytic reactions via evolutions of both surface morphology and electronic structures, including dehydrogenation, CO oxidation on metal-based substrates, and so on. In the end, a perspective is also given regarding the combination of in situ X-ray photoelectron spectroscopy (XPS) and STM towards the identification of the structure-performance relationship.

PtCuNi Tetrahedra Catalysts with Tailored Surfaces for Efficient Alcohol Oxidation

Direct methanol/ethanol alkaline fuel cells (DMAFCs/DEAFCs) represent an attractive mobile power generation technology. The methanol/ethanol oxidation reaction (MOR/EOR) often requires high-performance yet expensive Pt-based catalysts that may be easily poisoned. Herein, we report the development of PtCuNi tetrahedra electrocatalysts with optimized specific activity and mass activity for MOR and EOR. Our synthetic and structural characterizations show that these PtCuNi tetrahedra have Cu-rich core and PtNi-rich shell with tunable surface composition. Electrocatalytic studies demonstrate that Pt₅₆Cu₂₈Ni₁₆ exhibits exceptional MOR and EOR specific activities of 14.0 ± 1.0 mA/cm² and 11.2 ± 1.0 mA/cm², respectively and record high mass activity of 7.0 ± 0.5 A/mg_Pt and 5.6 ± 0.6 A/mg_Pt, comparing favorably with the best MOR or EOR Pt alloy-based catalysts reported to date. Furthermore, we show that the unique core-shell tetrahedra configuration can also lead to considerably improved durability.

Room-temperature electrochemical water-gas shift reaction for high purity hydrogen production

Traditional water–gas shift reaction provides one primary route for industrial production of clean-energy hydrogen. However, this process operates at high temperatures and pressures, and requires additional separation of H₂ from products containing CO₂, CH₄ and residual CO. Herein, we report a room-temperature electrochemical water–gas shift process for direct production of high purity hydrogen (over 99.99%) with a faradaic efficiency of approximately 100%. Through rational design of anode structure to facilitate CO diffusion and PtCu catalyst to optimize CO adsorption, the anodic onset potential is lowered to almost 0 volts versus the reversible hydrogen electrode at room temperature and atmospheric pressure. The optimized PtCu catalyst achieves a current density of 70.0 mA cm⁻² at 0.6 volts which is over 12 times that of commercial Pt/C (40 wt.%) catalyst, and remains stable for even more than 475 h. This study opens a new and promising route of producing high purity hydrogen.

Traditional water–gas shift reaction process is hindered by harsh reaction conditions and extra steps for hydrogen separation and purification. Here, the authors report a room temperature electrochemical water–gas shift process for direct production of high purity hydrogen with a faradaic efficiency of approximately 100%.

High performance of PtCu@TiO2 nanocatalysts toward methanol oxidation reaction: from synthesis to molecular picture insight

The electrocatalytic production of hydrogen from methanol dehydrogenation successfully uses platinum catalysts. However, they are expensive and Pt has the tendency to be poisoned from the intermediate compounds, formed during the methanol oxidation reaction (MOR). For these two reasons, there has been active research for alternative bi- and tri-component Pt-based catalysts. Herein, PtCu nanoparticles deposited on titania were studied and proposed to be efficient MOR catalysts. The catalyst was prepared by photo-deposition of Cu on a high-surface-area TiO₂ powder support, followed by a partial galvanic displacement of the Cu deposit by platinum. The morphology and structure of the catalyst were characterized by physicochemical methods. The PtCu@TiO₂ electro-catalyst has higher intrinsic catalytic activity and comparable mass specific activity for MOR in comparison with a commercial Pt/C catalyst. The experimental analyses were complemented by density functional theory-based computations. The theoretical results revealed that the most energetically favorable Pt and Cu arrangement in the supported PtCu nanoparticles was core (Cu)–shell (Pt) and/or phase-separated. The inter-atomic interactions responsible for the bimetallic cluster stabilization on titania were highlighted from the computed electronic charge distribution.

Computed adhesion energies of pure and bimetallic PtCu clusters (regular alloy, phase-separated, core–shell) on TiO₂ anatase support.

Lonely Atoms with Special Gifts: Breaking Linear Scaling Relationships in Heterogeneous Catalysis with Single-Atom Alloys

We discuss a simple yet effective strategy for escaping traditional linear scaling relations in heterogeneous catalysis with highly dilute bimetallic alloys known as single-atom alloys (SAAs). These systems, in which a reactive metal is atomically dispersed in a less reactive host, were first demonstrated with the techniques of surface science to be active and selective for hydrogenation reactions. Informed by these early results, PdCu and PtCu SAA nanoparticle hydrogenation catalysts were shown to work under industrially relevant conditions. To efficiently survey the many potential metal combinations and reactions, simulation is crucial for making predictions about reactivity and guiding experimental focus on the most promising candidate materials. This recent work reveals that the high surface chemical heterogeneity of SAAs can result in significant deviations from Brønsted-Evans-Polanyi scaling relationships for many key reaction steps. These recent insights into SAAs and their ability to break linear scaling relations motivate discovery of novel alloy catalysts.

How Au Outperforms Pt in the Catalytic Reduction of Methane towards Ethane and Molecular Hydrogen

Within the context of a "hydrogen economy", it is paramount to guarantee a stable supply of molecular hydrogen to devices such as fuel cells. At the same time, catalytic conversion of the environmentally harmful methane into ethane, with a significantly lower Global Warming Potential, turns into a highly desirable challenge. Herein we propose a first-step novel proof-of-concept mechanism to accomplish both tasks simultaneously. For that purpose we provide transition-state barriers and reaction Helmholtz free energies obtained from first-principles Density Functional Theory by taking account vibrations for 2CH₄(g) → C₂H₆(g) + H₂(g) to show that molecular hydrogen can be produced by subnanometer Pt₃₈ and Au₃₈ nanoparticles from natural gas. Interestingly, the active sites for the reaction are located on different planes on the two nanoparticles, effectively differentiating the working principle of the two metals. The analysis shows that the complete cycle to reduce CH₄ can be performed on Au and Pt with similar efficiencies, but Au requires only half the working temperature of Pt. This substantial decrease of temperature can be traced back to several intermediate steps, but most crucially to the final one where the catalyst must be cleaned from H(⋆) to be able to restart the catalytic cycle. This simple study case provides useful guidelines to capitalize on finite-size effects in small nanoparticles for the design of new and more efficient catalysts. Interestingly, present results obtained for the intermediate steps of the catalytic cycle show an excellent agreement with previous experimental evidence. Finally, we stress the importance of including the final cleaning steps to start a new fresh catalytic cycle.

In situ spectroscopic studies of the one-pot synthesis of composition-controlled Cu–Ni nanowires with enhanced catalytic activity

Development of a novel alcohol reduction technique for the one-pot synthesis of Cu–Ni NWs by elucidating the formation mechanism by using in situ spectroscopic measurements.

Finite Size Effects in Submonolayer Catalysts Investigated by CO Electrosorption on PtsML/Pd(100)

A combination of scanning tunneling microscopy, subtractively normalized interfacial Fourier transform infrared spectroscopy (SNIFTIRS), and density functional theory (DFT) is used to quantify the local strain in 2D Pt clusters on the 100 facet of Pd and its effect on CO chemisorption. Good agreement between SNIFTIRS experiments and DFT simulations provide strong evidence that, in the absence of coherent strain between Pt and Pd, finite size effects introduce local compressive strain, which alters the chemisorption properties of the surface. Though this effect has been widely neglected in prior studies, our results suggest that accurate control over cluster sizes in submonolayer catalyst systems can be an effective approach to fine-tune their catalytic properties.

Fast Prediction of CO Binding Energy via the Local Structure Effect on PtCu Alloy Surfaces

CO poisoning is a major problem for Pt-based catalysts in various catalytic processes. Thus, the prediction of CO binding energies over Pt alloy surfaces is fundamentally important to evaluate their CO poisoning tolerance. This article describes the effect of surface and subsurface coordination environments on the CO binding strength over PtCu alloy surfaces by employing density functional theory calculations. We show that the existence of surface Pt neighbors weakens the CO binding strength on Pt, whereas the subsurface Pt neighbors play the opposite role. Crystal orbital Hamilton population analysis suggests a stronger antibonding interaction for the Pt_surface-Pt_subsurface bond than for the Pt_surface-Pt_surface bond, which indicates less stable subsurface Pt atoms that hence generate an activated surface Pt that attracts CO more strongly. On the basis of the calculated CO binding energies, an empirical formula, with Pt-Pt coordination numbers as the variables, has been fitted to achieve a fast prediction of CO binding energy over PtCu alloy surfaces.

Prediction of metallic nanotube reactivity for H2O activation

The reactivity of metallic nanotubes toward the catalysis of water dissociation, a key step in the water gas shift reaction (WGSR), was analyzed through density functional theory (DFT) calculations. Water dissociation was studied on surfaces of nanotubes based on copper, gold and platinum, and also on platinum doped copper and gold nanotubes. Gold and copper nanotubes present activities that are similar to those of their corresponding extended surfaces but, in the case of the Pt(5,3) nanotube, a significant improvement in the activity is found when compared with the extended surfaces. In fact, the calculations predict the water dissociation to be spontaneous on Pt(5,3) with a low activation energy barrier. The platinum doping of gold and copper nanotubes leads to contrasting effects, i.e., with a slight increase of activity found on gold and a slight decrease of activity in the case of copper. The consideration of a Brönsted-Evans-Polanyi (BEP) relationship to estimate the activation energy barriers for the O-H bond break leads to a satisfactory agreement between estimated and explicitly calculated values which suggests the validity of the BEP relationship for qualitative predictions of the activities of metal nanotubes towards the water dissociation reaction.

First-principles study of single transition metal atoms on ZnO for the water gas shift reaction

A single Ni atom substituted on a ZnO surface is a promising catalyst for the water gas shift reaction.

Descriptors and Thermodynamic Limitations of Electrocatalytic Carbon Dioxide Reduction on Rutile Oxide Surfaces

A detailed understanding of the electrochemical reduction of CO₂ into liquid fuels on rutile metal oxide surfaces is developed by using DFT calculations. We consider oxide overlayer structures on RuO₂ (1 1 0) surfaces as model catalysts to elucidate the trends and limitations in the CO₂ reduction reaction (CO2RR) based on thermodynamic analysis. We aim to specify the requirements for CO2RR catalysts to establish adsorbate scaling relations and use these to derive activity volcanoes. Computational results show that the OH* binding free energy is a good descriptor of the thermodynamic limitations and it defines the left leg of the activity volcano for CO2RR. HCOOH* is a key intermediate for products formed through further reduction, for example, methanediol, methanol, and methane. The surfaces that do not bind HCOOH* are selective towards formic acid (HCOOH) production, but hydrogen evolution limits their suitability. We determine the ideal binding free energy for H* and OH* to facilitate selective CO2RR over H₂ /CO evolution to be ΔG_B [H]>0.5 eV and -0.5 eV<ΔG_B [OH]<0.1 eV. The Re-containing overlayers considered in this work display excellent promise for selectivity, although they are active at a highly reducing potential.

A cooperative pathway for water activation using a bimetallic Pt0–CuI system

Cooperative activation of a water molecule with a bimetallic platinum(0)–copper(i) system results in formation of copper(i) hydroxide and a platinum hydride species. The latter is stable under acidic and neutral conditions but undergoes cyclometalation in the presence of pyridine.

The effect of an Fe promoter on Cu/SiO2 catalysts for improving their catalytic activity and stability in the water-gas shift reaction

By adding a small amount of iron, the catalytic activity and stability of Cu/SiO₂ are effectively improved.

A DFT study of molecular adsorption on Au–Rh nanoalloys

Density functional theory calculations are performed to investigate both mixing and adsorption properties of 38-atom and 79-atom Au–Rh nanoalloys at the nanoscale.