Strong Metal-support Interaction Research Articles

Iron-based heterojunction activate strong metal-support interaction enabling hydrogen evolution reaction at ampere-level current density in seawater

Exploring Ru-based materials with strong metal-support interaction (SMSI) is a promising method to develop superb activity and long-term durability electrocatalysts for hydrogen evolution reaction (HER). Herein, a heterojunction substrates strategy is proposed to stimulate the intrinsic activity of Ru nanoparticles loading on FeTeO (Ru/FeTeO) by activating the strong metal-heterojunction substrate interaction (SMHSI). Density functional theory (DFT) and in-situ tests uncover that FeTeO heterojunction substrates can further boost the HER activity by modulating the electronic structure and H adsorption energy. Consequently, the as-prepared Ru/FeTeO possesses outstanding HER activity with low overpotentials of 244 and 311 mV to drive 1.0 and 3.0 A cm−2 current densities in 1.0 M KOH seawater solution, respectively, and displays a long-term stability more than 150 h. This work supplies an effective way to stimulate the intrinsic activity of precious metals.

Mechanistic and kinetics insights into Cu size effects on catalytic hydrogen combustion

The removal of excess hydrogen in a catalytic process is a safety measure, which should be incorporated into fuel cell technologies. In this study, the size effects of Cu catalysts on the catalytic hydrogen combustion are examined by investigating the impact of Cu–Cu and Cu–O coordination numbers. A distinct volcano-shaped trend in catalytic performance is observed, reaching its peak when the Cu loading is at 5 wt% with a reaction rate of 0.55 molH2·molCu−1·min−1. It is found that the lower Cu loading leads to strong metal-support interactions and a high Cu–O coordination, whereas the higher Cu loading hinders reduction and increases the Cu–Cu coordination. DFT calculations emphasize the significance of Cu(111) facets in facilitating HH bond dissociation and OH bond formation. However, excessively large Cu nanoparticles limit catalytic activity due to the reduced active sites. As a result, the 5 wt% Cu/γ-Al2O3 catalyst, which strikes a balance between Cu–Cu and Cu–O coordination numbers, exhibits the highest catalytic performance for this reaction. This study not only provides valuable insights into the size effects of Cu–based catalysts on hydrogen combustion, but also offers guidance for designing highly active Cu–based catalysts.

Encapsulation of Highly Dispersed Au NPs by Strong Metal–Support Interactions in Porous Titania Nanoplates for Efficient Electrosynthesis of H2O2

AbstractTuning the electrocatalytic selectivity and long‐term stability for industrially significant, yet reactively unfavorable products, remains a challenge in oxygen reduction. Herein, the Au/TiO2 catalysts with strong metal–support interactions (SMSI) are designed and synthesized through an in situ auto‐reduction of Au‐modified Ti‐MOF. Highly dispersed ultra‐low loading of Au NPs strongly capsulated in porous TiO2 substrate, together with conductive carbon derivated from MOFs, enables Au/TiO2 electrocatalysts to achieve excellent H2O2 electrosynthesis through the two‐electron oxygen reduction reaction (2e ORR). Au(1.0)/TiO2 (0.52 wt% Au loading) exhibited a high selectivity of 90%, a remarkable Faradaic efficiency of 98%, and 72.2 mg L−1 h−1 H2O2 production. Highly dispersed Au NPs promote active site exposure, while the conductive carbon and the porous superstructure enhance mass diffusion. Notably, the SMSI between Au NPs and TiO2 substrate leads to superb stability (over 168 h) of the electrocatalysts, as it ensures continuous electronic interactions. Experimental characterizations and density functional theory (DFT) simulations further revealed that the SMSI effect medicates the activation of the *OOH intermediate formation and the d‐band center, which are conductive to 2e ORR. Moreover, this strategy provides a potential way toward high‐performance electrocatalysts in flow system devices for continuously purifying sewage and chemical bleaching in extreme environments.

Tuning the CO2 Hydrogenation Activity via Regulating the Strong Metal–Support Interactions of the Ni/Sm2O3 Catalyst

Tuning the CO₂ Hydrogenation Activity via Regulating the Strong Metal–Support Interactions of the Ni/Sm₂O₃ Catalyst

Dynamic Behavior of Platinum Atoms and Clusters in the Native Oxide Layer of Aluminum Nanocrystals.

Strong metal-support interactions (SMSIs) are well-known in the field of heterogeneous catalysis to induce the encapsulation of platinum (Pt) group metals by oxide supports through high temperature H2 reduction. However, demonstrations of SMSI overlayers have largely been limited to reducible oxides, such as TiO2 and Nb2O5. Here, we show that the amorphous native surface oxide of plasmonic aluminum nanocrystals (AlNCs) exhibits SMSI-induced encapsulation of Pt following reduction in H2 in a Pt structure dependent manner. Reductive treatment in H2 at 300 °C induces the formation of an AlOx SMSI overlayer on Pt clusters, leaving Pt single-atom sites (Ptiso) exposed available for catalysis. The remaining exposed Ptiso species possess a more uniform local coordination environment than has been observed on other forms of Al2O3, suggesting that the AlOx native oxide of AlNCs presents well-defined anchoring sites for individual Pt atoms. This observation extends our understanding of SMSIs by providing evidence that H2-induced encapsulation can occur for a wider variety of materials and should stimulate expanded studies of this effect to include nonreducible oxides with oxygen defects and the presence of disorder. It also suggests that the single-atom sites created in this manner, when combined with the plasmonic properties of the Al nanocrystal core, may allow for site-specific single-atom plasmonic photocatalysis, providing dynamic control over the light-driven reactivity in these systems.

Strong Metal‐Support Interactions: From Characterization, Manipulation to Application in Fischer‐Tropsch Synthesis and Atmospheric CO2 hydrogenation

AbstractStrong metal‐support interactions (SMSI) featuring the formation of encapsulation overlayer around metal nanoparticles has drawn much attention in heterogeneous catalysis. Recent years, various novel SMSI phenomena have been observed and the nature of SMSI also has been revealed with the improvement of characterization techniques. Understanding the SMSI effect could deepen the insight into the structure‐activity relationship of metal‐supported catalysts, and rationally guide the design of special metal‐interface sites to manipulate catalytic behavior in chemical reaction. In this review, the research progress of SMSI and its application in heterogeneous COx hydrogenation are briefly surveyed, with emphasis on the advanced characterization, manipulation strategy and specific role of SMSI in Fischer‐Tropsch synthesis process, CO2 methanation and Reverse Water Gas Shift reaction. The current challenges and perspectives for the development of SMSI are also discussed.

Which is better for converting furfural into furfuryl alcohol: The strong metal-support interaction effect or the formation of alloy?

Furfural, one of biomass raw materials, can be seen as a clean alternative energy to fossil energy. Cu-based catalysts have been studied mostly due to the excellent selectivity to furfuryl alcohol. While keeping the stability of Cu-based catalysts under high temperature is still a challenge. Thus, a more active and stable Ni-based catalyst is researched. While the high yield of furfuryl alcohol was difficult to obtained over Ni catalysts. A catalyst (5 % Ni/Ce0.9Sn0.1O2) that combines stability and selectivity was prepared with enhanced activity which was different with the NiSn alloy. Combined with the characterizations of XRD, XPS, TEM, CO-TPD and H2-TPR, it has been proven that the enhanced strong interaction between Ni and Ce0.9Sn0.1O2 is much more effective in forming furfuryl alcohol than the effect of the Ni3Sn4 alloy.

Construction of a Metal-Silica Interface for Semihydrogenation of Alkynes.

Fabricating optimum surface structures represents an attractive approach for synthesizing supported catalysts with high activity and specific selectivity. New active sites could be flexibly constructed via the strong metal-support interaction under the redox condition. Herein, we demonstrated the formation of a new Rh-Si surface on a silica-modified carbon nanotube supported Rh catalyst under the high-temperature reduction condition as well as a thin amorphous silica coating layer and weak chemisorption toward the CO molecule. The electronic interactions between Rh and Si, along with the particular structure, guarantee desirable catalytic performance for the semihydrogenation of phenylacetylene under mild conditions. This facile approach might be extensively used in constructing new active sites with robust activity and specific selectivity in diverse heterogeneous catalysis systems.

Unique Possibilities of Dynamic Metal–Polymer Interactions in Selective Hydrogenation

AbstractRationally designed polymers can function as supports or promoters for metal catalysts, imparting distinct catalytic properties in selective hydrogenation. With strongly metal–ligating functional groups, mobile polymer chains can spontaneously decorate the metal catalyst surfaces under mild conditions, forming stable metal–polymer interfaces. We have termed this phenomenon ‘dynamic metal–polymer interaction (DMPI),’ which can be roughly considered as an organic version of the strong metal–support interaction (SMSI) concept. The polymer chains that dynamically interact with the metal surface can control the adsorption of reactants and products through competitive adsorption, significantly improving selectivity and catalyst stability. One of the remarkable advantages of using polymers as catalytic materials is that their molecular structures, such as molecular weight, crystallinity, and chemical functionality, can be tailored using rich organic chemistry. This, in turn, allows us to precisely tune the metal–polymer interactions and catalytic properties. In this Concept, we will discuss how metal–polymer interfaces can be designed and utilized for selective hydrogenation, with a particular emphasis on the industrially relevant acetylene partial hydrogenation reaction.

Catalytic propane dehydrogenation by anatase supported Ni single-atom catalysts

With the increasing production of propane from shale gas and the growing demand for propylene, propane dehydrogenation (PDH) has gained significant attention as a promising route for the on-purpose production of propylene. As a cheap yet efficient catalyst, Ni-based catalysts have attracted interest because of its ability to activate alkane. Single-atom catalysts (SACs) can maximize the metal atom utilization. Here, we demonstrate that anatase TiO2 supported Ni SAC (Ni1/A-TiO2) exhibits not only superior intrinsic activity and propylene selectivity but also much better stability than the corresponding Ni nanoparticle (NP) catalyst (NiNP/A-TiO2) in PDH reaction at 580 °C. The rate of propylene production on Ni1/A-TiO2 is about 1.96 molC3H6 gNi−1 h−1, about 65 times higher than that of NiNP/A-TiO2 sample (0.03 molC3H6 gNi−1 h−1). In combination of high-angle annular dark-field scanning transmission electron microscopy, in-situ diffuse reflectance infrared Fourier transform spectra, in-situ X-ray photoelectron spectroscopy and X-ray absorption spectroscopy characterizations, we confirm that the Ni SAC mainly contains individual Ni atom singly dispersed on the support in positive Ni (II) valence state. In addition, as a result of strong metal-support interaction (SMSI) between Ni NP and TiO2 carrier under reduced conditions, the Ni NPs sites are encapsulated by TiOx overlayer (~2 nm thick) thus display poor reaction performance.

Unveiling the Morphology of Carbon-Supported Ru Nanoparticles by Multiscale Modeling.

Simulating the behavior of metal nanoparticles on supports is crucial for boosting their catalytic performance and various nanotechnology applications; however, such simulations are limited by the conflicts between accuracy and efficiency. Herein, we introduce a multiscale modeling strategy to unveil the morphology of Ru supported on pristine and N-doped graphene. Our multiscale modeling started with the electronic structures of a supported Ru single atom, revealing the strong metal-support interaction around pyridinic nitrogen sites. To determine the stable configurations of Ru2-13 clusters on three different graphene supports, global energy minimum searches were performed. The sintering of the global minimum Ru13 clusters on supports was further simulated by ab initio molecular dynamics (AIMD). The AIMD data set was then collected for deep potential molecular dynamics to study the melting of Ru nanoparticles. This study presents comprehensive descriptions of carbon-supported Ru and develops modeling approaches that bridge different scales and can be applied to various supported nanoparticle systems.

High density ultra-small Cu nanoparticles with abundant oxygen vacancies for efficient hydrogen evolution from MeOH/H2O

Efficient release of H2 with negligible CO impurities from sustainable MeOH/H2O has become a promising goal for on-board hydrogen generator. However, hydrogen release kinetics still face challenges. In this work, the Cu/ZnO/CeO2 catalyst with high density ultra-small Cu nanoparticles and abundant oxygen vacancies were prepared for intensifying hydrogen evolution in aqueous phase reforming of methanol (APRM). The optimized 55% Cu/ZnO/CeO2 catalyst (Cu NPs of 3.8 nm, Cu loading of 55.89 wt%, oxygen vacancies of 2.316 × 1015 spins g−1) exhibited an excellent H2 evolution rate of 58.39 μmolgcat−1 s−1 even at low temperature of 210 °C, which was 2.1-fold enhancement than that of commercial Cu/ZnO/Al2O3 catalyst. Characterizations and experiments revealed that ZnO/CeO2 intensified the strong metal-support interaction (SMSI), which anchored the Cu NPs, generated abundant oxygen vacancies and adjusted electronic structure to form Cu0-Cu+-Ov active sites for facilitating the kinetics of APRM.

Exploration of Strong Metal‐Support Interaction in Heterogeneous Catalysts by in situ Transmission Electron Microscopy

AbstractThe phenomenon of strong metal‐support interaction (SMSI) observed in supported metal catalysts, usually accompanied by the formation of the encapsulation layer on metal nanoparticles, has attracted extensive research attention due to its significance in heterogeneous catalysis. Notably, great progress has been made in recent years in investigating SMSI by in situ transmission electron microscopy (TEM), along with an enhanced comprehension of the underlying mechanisms governing SMSI formation. This emerging topic summarizes recent progress utilizing in situ TEM to study the interaction between metal and support and the relationship between the structure and performance of the supported catalyst under reaction conditions. A brief perspective about the use of in situ TEM for further study of SMSI is also presented, showing prospects in this field that will stimulate further upsurging research in promoting the catalytic efficiency of supported catalysts.

Renaissance of Strong Metal-Support Interactions.

Strong metal-support interactions (SMSIs) have emerged as a significant and cutting-edge area of research in heterogeneous catalysis. They play crucial roles in modifying the chemisorption properties, interfacial structure, and electronic characteristics of supported metals, thereby exerting a profound influence on the catalytic properties. This Perspective aims to provide a comprehensive summary of the latest advancements and insights into SMSIs, with a focus on state-of-the-art in situ/operando characterization techniques. This overview also identifies innovative designs and applications of new types of SMSI systems in catalytic chemistry and highlights their pivotal role in enhancing catalytic performance, selectivity, and stability in specific cases. Particularly notable is the discovery of SMSI between active metals and metal carbides, which opens up a new era in the field of SMSI. Additionally, the strong interactions between atomically dispersed metals and supports are discussed, with an emphasis on the electronic effects of the support. The chemical nature of SMSI and its underlying catalytic mechanisms are also elaborated upon. It is evident that SMSI modification has become a powerful tool for enhancing catalytic performance in various catalytic applications.

Oxygen vacancy of Pt/CeO2 enabled low-temperature hydrogen generation from methanol and water

Aqueous-phase reforming of methanol (APRM) represents an alternative approach to achieve a sustainable hydrogen generation and safe storage. Nonetheless, the limitations imposed by the high operating temperatures of heterogeneous catalysts serve as a bottleneck for the widespread adoption of this system. Herein, we demonstrated that the Pt nanoparticles supported on porous nanorods of CeO2 with abundant oxygen vacancies (Pt/PN-CeO2) enabled the efficient H2 generation through low-temperature (<60 °C) APRM reaction. The presence of oxygen vacancies on PN-CeO2 could enhance the electronic density of supported Pt nanoparticles through strong metal-support interaction, thereby promoting the activation of methanol. Meanwhile, the oxygen vacancies could further promote the H2O activation. Consequently, the interface between Pt and PN-CeO2 enabled efficient H2 generation at 60 °C with a TOF values of 173.5 h−1 and suppress CO generation. This finding provides a promising pathway towards the low-temperature APRM reaction.

Tuning Strong Metal‐Support Interactions for Enhancing Direct Deoxygenation of Biomass‐Lignin Derived Phenolics

AbstractCatalytic direct deoxygenation (DDO) of phenolic compounds to aromatics is an appealing approach for utilization of biomass‐lignin with minimal amount of H2 consumption. Metal/reducible metal oxide catalysts provide two functionalities, i. e., C−H bond formation (hydrogenation) and C−O bond breakage (deoxygenation), required for this reaction that takes place at the interfacial perimeter sites. Strong metal‐support interactions (SMSI) can profoundly alter the density and property of such sites. This short review summarized recent advances in tuning SMSI for enhancing DDO of phenolics. The approaches of varying reduction temperature, modulation of crystal facets and crystal phases of metal oxide, and reduction of mixed metal oxide were discussed for the origin for formation of SMSI, the degree of SMSI, and its consequence on the DDO performance. The analysis revealed that intermediate degree of SMSI with maximal density of metal/oxide interfacial perimeter site enhances DDO while minimizing unfavorable side reactions. This short review highlights the concept of tuning the interfacial perimeter sites via SMSI for reactions which require multiple functionalities and take place at the metal/oxide interface.

Site-specific metal-support interaction to switch the activity of Ir single atoms for oxygen evolution reaction

The metal-support interactions (MSI) could greatly determine the electronic properties of single-atom catalysts, thus affecting the catalytic performance. However, the typical approach to regulating MSI usually suffers from interference of the variation of supports or sacrificing the stability of catalysts. Here, we effectively regulate the site-specific MSI of Ir single atoms anchored on Ni layered double hydroxide through an electrochemical deposition strategy. Cathodic deposition drives Ir atoms to locate at three-fold facial center cubic hollow sites with strong MSI, while anodic deposition drives Ir atoms to deposit onto oxygen vacancy sites with weak MSI. The mass activity and intrinsic activity of Ir single-atom catalysts with strong MSI towards oxygen evolution reaction are 19.5 and 5.2 times that with weak MSI, respectively. Mechanism study reveals that the strong MSI between Ir atoms and the support stimulates the activity of Ir sites by inducing the switch of active sites from Ni sites to Ir sites and optimizes the adsorption strength of intermediates, thereby enhancing the activity.

Fabrication of NiTi-MMO supported on in-situ generated TiO2 for dioctyl phthalate hydrogenation: A strategy for improving the utilization efficiency of Ni

In this work, a NiTi-MMO/TiO2-R catalyst was prepared by in-situ generation of a TiO2 support during hydrothermal synthesis of the hydrotalcite precursor for NiTi-MMO. The formation of NiTi-MMO can reduce the size of metallic Ni particles, which can significantly improve the catalyst's activity, and the in-situ generated TiO2 support can enhance the dispersion of NiTi-MMO and the utilization efficiency of the active nickel species. The NiTi-MMO/TiO2-R catalyst showed high activity for the hydrogenation of dioctyl phthalate to dioctyl-1,2-cyclohexanedicarboxylate. The catalyst also exhibited good stability, maintaining the yield over 90 % after 6 cycles. Characterization results showed that a strong metal-support interaction was formed between the in-situ generated TiO2 support and the metallic Ni particles produced by the reduction of NiTi-MMO. The strong metal-support interactions formed between metallic Ni particles and the in-situ generated TiO2 played a crucial role in stabilizing the nickel species and preventing their aggregation, resulting in superior catalytic performance.

Platinum-Ruthenium Dual-Atomic Sites Dispersed in Nanoporous Ni0.85 Se Enabling Ampere-Level Current Density Hydrogen Production.

Alkaline anion-exchange-membrane water electrolyzers (AEMWEs) using earth-abundant catalysts is a promising approach for the generation of green H2 . However, the AEMWEs with alkaline electrolytes suffer from poor performance at high current density compared to proton exchange membrane electrolyzers. Here, atomically dispersed Pt-Ru dual sites co-embedded in nanoporous nickel selenides (np/Pt1 Ru1 -Ni0.85 Se) are developed by a rapid melt-quenching approach to achieve highly-efficient alkaline hydrogen evolution reaction. The np/Pt1 Ru1 -Ni0.85 Se catalyst shows ampere-level current density with a low overpotential (46mV at 10mAcm-2 and 225mV at 1000mAcm-2 ), low Tafel slope (32.4mVdec-1 ), and excellent long-term durability, significantly outperforming the benchmark Pt/C catalyst and other advanced large-current catalysts. The remarkable HER performance of nanoporous Pt1 Ru1 -Ni0.85 Se is attributed to the strong intracrystal electronic metal-support interaction (IEMSI) between Pt-Se-Ru sites and Ni0.85 Se support which can greatly enlarge the charge redistribution density, reduce the energy barrier of water dissociation, and optimize the potential determining step. Furthermore, the assembled alkaline AEMWE with an ultralow Pt and Ru loading realizes an industrial-level current density of 1Acm-2 at 1.84volts with high durability.

Hydrogenation of waste PET degraded bis(2-hydroxyethyl)cyclohexane- 1,4-dicarboxylate to 1,4-cyclohexanedimethanol over Cu-based catalysts

Upcycling of waste polyethylene terephthalate derived bis(2-hydroxyethyl) cyclohexane-1,4-dicarboxylate (BHCD) to valuable monomer (1,4-cyclohexanedimethanol, CHDM) can decrease the emission of CO2 and microplastics. In this work, a stable Cu-based catalyst (Cu/MgAl2O4) with strong metal-support interaction was synthesized via calcination and reduction of CuMgAl-LDH precursor. The properties of precursor and final catalyst were characterized using XRD, TG-DTA, N2-adsorption, SEM/TEM, H2-TPR, CO2/NH3-TPD and XPS techniques. It was found that Cu/MgAl2O4 has high surface area, strong metal-support interaction and plenty basic sites. Cu/MgAl2O45 exhibited prominent performance for the hydrogenation of PET-derived BHCD to CHDM among the tested Cu/MgAl2O4, Cu/MnAl2O4 and Cu/ZnAl2O4 catalyst. The yield of CHDM over Cu/MgAl2O4 reached 98 % with a complete conversion of BHCD at 240 °C, 4 MPa and 0.525 g.gcat-1.h−1. Besides, it remains its activity for at least 80 h on stream under optimized condition. The structure-performance of these catalysts for the hydrogenation of BHCD to CHDM was discussed.