Strong Metal-support Interaction Research Articles

A systematic study on Au-PDA@Fe3O4 core-shell catalysts for enhanced catalytic reduction of 4-nitrophenol

The development of nanogold catalysts with high activity and high stability is of great significance for their industrial applications. In this paper, Au-PDA@Fe3O4 catalysts were prepared through the gold sol adsorption method. First, micron-sized magnetic Fe3O4 spheres were synthesized via a solvothermal method, serving as the core to endow the catalyst with excellent recyclability. Subsequently, a layer of polydopamine (PDA) shell was polymerized on the magnetic core surface. By controlling the timing of introducing the gold sol containing Au nanoparticles (NPs), the spatial position of Au NPs within the PDA layer was regulated, leading to a series of magnetic core-shell nano gold catalysts with varying spatial positions of Au. Using the 4-nitrophenol (4-NP) hydrogenation as the probe, the influence of Au spatial position, Au size, and other conditions on the catalytic performance was investigated. Results showed that, in the prepared Au-PDA@Fe3O4-16 catalyst, the Au NPs are encapsulated within the PDA shell and positioned close to the outer layer. This not only provides remarkable stability to the Au NPs but also maintains their proximity to the surface of the PDA shell, allowing easier access of the substrate 4-NP to the Au NPs and conferring good reactivity upon the catalyst. The strong electron metal-support interaction between PDA and Au enables PDA to effectively stabilize Au NPs. The prepared Au-PDA@Fe3O4-16 catalyst exhibits excellent stability, maintaining a high conversion rate of 91% even after 14 cycles of use. Our findings not only deepen the understanding of the catalytic mechanisms involved but also pave the path towards the creation of highly efficient and robust gold-based catalysts, facilitating their widespread utilization in industrial applications.

Strong Metal-Support Interaction between Pt and TiO2 over High-temperature CO2 Hydrogenation.

The catalytic activities and stability of oxide-supported metal catalysts are significantly affected by metal-support interactions (MSI) between oxidic supports and supported metals. The surface properties of the support, such as its phase and defects, are crucial in MSI, including both the strong metal-support interaction (SMSI) and electronic metal-support interaction (EMSI). In this study, modulation of SMSI was achieved on rutile-supported Pt nanoparticles (NP) over high-temperature CO2 hydrogenation. The encapsulation of Pt NP surfaces with TiO2-x overlayers is precisely controlled by the defects. It is found that oxygen vacancy defects significantly enhance the catalytic stability of Pt/rutile under high-temperature reverse water-gas shift (RWGS) reaction by inhibiting the occurrence of SMSI. Pt/rutile with oxygen vacancies achieves a 301 molCO×gM-1×h-1 space time yield and considerably catalytic stability (decreased by 8%) at 800 °C over 100 h time-on-stream. Density functional theory (DFT) calculations suggest that the adsorption capacity of Pt NP on the rutile overlayer can be reduced by increasing electron density. Experimental results combined with DFT calculations show that electron transfer from Pt NP to rutile is reduced by the oxygen vacancy defects on Pt/R, preserving the metallic nature of Pt species during CO2 hydrogenation, thereby preventing the formation of SMSI.

Recent Advances in Engineering Fe-N-C Catalysts for Oxygen Electrocatalysis in Zn-Air Batteries.

Fe-N-C single-atom catalysts (SACs) have emerged as one of the most promising candidates for oxygen electrocatalysis due to their maximized atom utilization efficiency, high intrinsic activity, and strong metal-support interaction. Significant progress has been made in engineering Fe-N-C SACs for oxygen electrocatalysis in Zn-air batteries (ZABs). This review provides a comprehensive overview of the recent advancements in Fe-N-C SACs, with a special focus on effective engineering strategies, their performance in oxygen electrocatalysis, and their potential applications in ZABs. The review also discusses the key challenges and future directions in the development of Fe-N-C SACs for efficient and durable oxygen electrocatalysis in ZABs. This review aims to offer valuable insights into the current state of research in this field and to guide future efforts in the development of advanced oxygen electrocatalysts for ZABs.

Coupling CoIr Nanoalloys with MXene by Lewis Acidic Molten Salt Etching for Wide-pH-Environment Hydrogen Evolution Reaction.

Metal/MXene-based materials show broad prospects in energy conversation through the strong metal-support interaction (SMSI). However, the difficulty and harshness of synthesis heavily limit their further application. Herein, using Lewis acidic molten salt to etch MAX as a precursor of MXene, a more convenient and safer strategy is designed to in situ construct the MXene-supported CoIr nanoalloy (CoIr/MXene) catalyst through Ti─O─M bond. The special layered structure and oxygen-containing functional group of MXene regulate the SMSI upon CoIr nanoalloys. Moreover, the contact angle and in situ Raman test results exhibit good interface hydrophilicity of MXene, enhancing the water adsorption on interfaces, and accelerating the mass transfer process. As a result, CoIr/MXene shows high hydrogen evolution reaction (HER) performance, which only needs overpotentials of 34 and 50mV to drive a current density of 10mA cm-2 in alkaline and acidic media, respectively, with excellent stability. Especially, in alkaline media, CoIr/MXene possesses 6 times higher HER mass activity (4.297 A mgIr -1) than commercial Pt/C catalysts (0.686 A mgPt -1) at the potential of 50mV, indicating larger active site density and intrinsic activity for CoIr/MXene. This work expands the application of the molten salt assist etching strategy and provides new insight for the development of metal/MXene-based catalysts.

Strong Metal-Support Interactions in Heterogeneous Oxygen Electrocatalysis.

Molecular oxygen redox electrocatalysis involves oxygen reduction and evolution as core reactions in various energy conversion and environmental technology fields. Strong metal-support interactions (SMSIs) based nanomaterials are regarded as desirable and state-of-the-art heterogeneous electrocatalysts due to their exceptional physicochemical properties. Over the past decades, considerable advancements in theory and experiment have been achieved in related studies, especially in modulating the electronic structure and geometrical configuration of SMSIs to enable activity, selectivity, and stability. In this focuses on the concept of SMSI, explore their various manifestations and mechanisms of action, and summarizes recent advances in SMSIs for efficient energy conversion in oxygen redox electrocatalysis applications. Additionally, the correlation between the physicochemical properties of different metals and supports is systematically elucidated, and the potential mechanisms of the structure-activity relationships between SMSIs and catalytic performance are outlined through theoretical models. Finally, the obstacles confronting this burgeoning field are comprehensively concluded, targeted recommendations and coping strategies are proposed, and future research perspectives are outlined.

Efficient and Ultrastable Seawater Electrolysis at Industrial Current Density with Strong Metal-Support Interaction and Dual Cl--Repelling Layers.

Direct seawater electrolysis is emerging as a promising renewable energy technology for large-scale hydrogen generation. The development of Os-Ni4Mo/MoO2 micropillar arrays with strong metal-support interaction (MSI) as a bifunctional electrocatalyst for seawater electrolysis is reported. The micropillar structure enhances electron and mass transfer, extending catalytic reaction steps and improving seawater electrolysis efficiency. Theoretical and experimental studies demonstrate that the strong MSI between Os and Ni4Mo/MoO2 optimizes the surface electronic structure of the catalyst, reducing the reaction barrier and thereby improving catalytic activity. Importantly, for the first time, a dual Cl- repelling layer is constructed by electrostatic force to safeguard active sites against Cl- attack during seawater oxidation. This includes a strong Os─Cl adsorption and an in situ-formed MoO4 2- layer. As a result, the Os-Ni4Mo/MoO2 catalyst exhibits an ultralow overpotential of 113 and 336mV to reach 500mA cm-2 for HER and OER in natural seawater from the South China Sea (without purification, with 1m KOH added). Notably, it demonstrates superior stability, degrading only 0.37 µV h-1 after 2500 h of seawater oxidation, significantly surpassing the technical target of 1.0 µV h-1 set by the United States Department of Energy.

Computational screening of Group VⅢ@C5N4 single-atom electrocatalysts for overall water splitting

Single-atom catalysts (SACs) have great potential for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) since their high atomic utilization and strong metal–support interactions. Herein, we develop TM@C5N4 (TM = Fe, Co, Ni, Ru, Rh, Pd, Os, Ir and Pt) catalysts via embedding Group VⅢ TM in holey C5N4 substrate and further evaluate their electrocatalytic activity using density functional theory (DFT) calculations. Systematical studies indicate that Fe@C5N4, Pd@C5N4 and Ir@C5N4 catalysts all exhibit excellent HER performance, which mainly because of their small ΔGH* values of 0.101 eV, -0.114 eV and 0.070 eV, respectively. In parallel, Rh@C5N4 and Ir@C5N4 possess high OER activity along with low overpotential of 0.50 V, which is superior to the commercial IrO2 catalyst (0.56 V). Obviously, Ir@C5N4 could be utilized as bifunctional electrocatalysts both HER and OER in water splitting. Furthermore, we analyze their correlative catalytic mechanisms using the molecular orbitals. Besides, biaxial strain modulation could effectively regulate the catalytic activity of HER and OER. Particularly, 2 % biaxial tensile strain could bring Ir@C5N4 superb HER/OER catalytic performance. Finally, we anticipate that this strain engineering would provide a new perspective for developing high-performance SACs for water splitting.

Facet-Dependent Diversity of Pt-O Coordination for Pt1/CeO2 Catalysts Achieved by Oriented Atomic Deposition.

The surface chemistry of CeO2 is dictated by the well-defined facets, which exert great influence on the supported metal species and the catalytic performance. Here we report Pt1/CeO2 catalysts exhibiting specific structures of Pt-O coordination on different facets by using adequate preparation methods. The simple impregnation method results in Pt-O3 coordination on the predominantly exposed {111} facets, while the photo-deposition method achieves oriented atomic deposition for Pt-O4 coordination into the "nano-pocket" structure of {100} facets at the top. Compared to the impregnated Pt1/CeO2 catalyst showing normal redox properties and low-temperature activity for CO oxidation, the photo-deposited Pt1/CeO2 exhibits uncustomary strong metal-support interaction and extraordinary high-temperature stability. The preparation methods dictate the facet-dependent diversity of Pt-O coordination, resulting in the further activity-selectivity trade-off. By applying specific preparation routes, our work provides an example of disentangling the effects of support facets and coordination environments for nano-catalysts.

Using In situ Transmission Electron Microscopy to Study Strong Metal-Support Interactions in Heterogeneous Catalysis.

Precisely controlling the microstructure of supported metal catalysts and regulating metal-support interactions at the atomic level are essential for achieving highly efficient heterogeneous catalysts. Strong metal-support interaction (SMSI) not only stabilizes metal nanoparticles and improves their resistance to sintering but also modulates the electrical interaction between metal species and the support, optimizing the catalytic activity and selectivity. Therefore, understating the formation mechanism of SMSI and its dynamic evolution during the chemical reaction at the atomic scale is crucial for guiding the structural design and performance optimization of supported metal catalysts. Recent advancements in in situ transmission electron microscopy (TEM) have shed new light on these complex phenomena, providing deeper insights into the SMSI dynamics. Here, the research progress of in situ TEM investigation on SMSI in heterogeneous catalysis is systematically reviewed, focusing on the formation dynamics, structural evolution during the catalytic reactions, and regulation methods of SMSI. The significant advantages of in situ TEM technologies for SMSI research are also highlighted. Moreover, the challenges and probable development paths of in situ TEM studies on the SMSI are also provided.

Embedding Reverse Electron Transfer Between Stably Bare Cu Nanoparticles and Cation-Vacancy CuWO4.

Cu nanoparticles (NPs) have attracted widespread attention in electronics, energy, and catalysis. However, conventionally synthesized Cu NPs face some challenges such as surface passivation and agglomeration in applications, which impairs their functionalities in the physicochemical properties. Here, the issues above by engineering an embedded interface of stably bare Cu NPs on the cation-vacancy CuWO4 support is addressed, which induces the strong metal-support interactions and reverse electron transfer. Various atomic-scale analyses directly demonstrate the unique electronic structure of the embedded Cu NPs with negative charge and anion oxygen protective layer, which mitigates the typical degradation pathways such as oxidation in ambient air, high-temperature agglomeration, and CO poisoning adsorption. Kinetics and in situ spectroscopic studies unveil that the embedded electron-enriched Cu NPs follow the typical Eley-Rideal mechanism in CO oxidation, contrasting the Langmuir-Hinshelwood mechanism on the traditional Cu NPs. This mechanistic shift is driven by the Coulombic repulsion in anion oxygen layer, enabling its direct reaction with gaseous CO to form the easily desorbed monodentate carbonate.

Crystalline-Amorphous IrOx Supported on Perovskite Nanotubes for pH-Universal OER.

Designing catalysts with desirable oxygen evolution reaction (OER) performance under pH-universal conditions is of great significance to promote the development of hydrogen production. Herein, we successfully synthesized a crystalline-amorphous IrOx supported on perovskite oxide nanotubes to obtain IrOx@La0.6Ca0.4Fe0.8Ni0.2O3 with superior OER performance in whole pH media. The overpotential of the IrOx@La0.6Ca0.4Fe0.8Ni0.2O3 catalyst in media of pH 14, 7.2, and 1 has been demonstrated to be 120, 400, and 143 mV, respectively, with no significant element dissolution as well as double-layer capacitance decay after the durability test. Through comparative experiments with IrOx@CNT and the physical mixture of IrOx and La0.6Ca0.4Fe0.8Ni0.2O3, it is found that the strong metal-support interaction (SMSI) in IrOx@La0.6Ca0.4Fe0.8Ni0.2O3 makes IrOx exist in an amorphous state rich in Ir3+, which is closely associated with the surface-active species Ir-OH. Through the regulation of Ir by a perovskite oxide support at the heterointerface, the reaction breaks through the limitation of the adsorbate evolution mechanism (AEM) and converts to a lattice-oxygen-mediated mechanism (LOM), which was fully demonstrated by the addition of the probe tetramethylammonium cation (TMA+), a LOM reaction intermediate, to the electrolyte. This work fills the research gap of perovskite oxide supported Ir-based catalysts with heterogeneous structures, providing an excellent strategy for the structural design of efficient pH-universal OER catalysts for hydrogen production systems.

Highly active ternary Ir/In2O3-ZrO2 catalyst for CO2 hydrogenation towards methanol: The role of zirconia

Indium oxide supported iridium catalyst has been verified to be highly active and selective for CO2 hydrogenation to methanol. In this work, zirconia is introduced into the Ir/In2O3 system as a novel Ir/In2O3-ZrO2 ternary catalyst. The solid solution generated between ZrO2 and In2O3 exhibits a strong electronic metal-support interaction with iridium, rendering the supported iridium species highly dispersed in a form of clusters. Thereout, an active interface between iridium and the solid-solution carrier is thus generated, on which electron transport is more feasible with a stronger CO2 adsorption than that of on the Ir−In2O3 interfacial site. Moreover, compared to Ir/In2O3, this ternary catalyst exhibits better catalytic activity as well as the stability. Density functional theory (DFT) simulations, combined with the in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) studies, further demonstrate the CO-hydrogenation pathway is the most favored for methanol synthesis, providing a rationale for the superior methanol selectivity of the Ir/In2O3-ZrO2 catalyst during CO2 hydrogenation.

Bifunctional fluorine doped Ru/RuO2 clusters with dynamic electron modification and strong metal-support interaction boost proton exchange membrane water electrolyzer

The sluggish kinetics and inherent instability over the Ru/RuO2 clusters are still enormous challenges in proton exchange membrane (PEM) water electrolyzer. Herein, we innovatively report synergistic modulation of dynamic electron modification and strong metal-support interaction (SMSI) to activate and stabilize bifunctional fluorine doped Ru/RuO2 clusters anchored on carbon nanotube (CNT), thus achieving efficient and stable acidic overall water splitting. Theoretical and experimental studies found that surface metal-fluorine modification layer could dynamically regulate the interfacial electronic environment to stabilize and activate multiple active Ru species; and the SMSI between Ru/RuO2 cluster and CNT maintains stable electronic environment for dynamic electron modification and avoids migrating or shedding of active species in acidic environment. Therefore, the PEM electrolyzer assembled with optimal F5.5-Ru/RuO2@CNT can operate stably for 100 h at a high current density of 100 mA cm−2, which is the first time that bifunctional Ru-based nanocatalysts applied to PEM device at a high current density.

A strong metal-support interaction strategy for enhanced proton-coupled electron transfer and promoted photocatalytic H2O2 production in pure water

Proton-coupled electron transfer (PCET) is a key factor in determining the H2O2 production efficiency from oxygen reduction reaction (ORR) or direct H2/O2 reaction, which usually requires the aid of proton donors including alcohols. Here, we report a strong metal-support interaction (SMSI) strategy to facilitate the PCET process of a typical Pd/TiO2 photocatalyst for photocatalytic ORR into H2O2 production in pure water. Compared to conventional Pd/TiO2 photocatalysts, the Pd/TiO2 photocatalyst with SMSI between Pd and TiO2 (Pd/TiO2-850H) promotes photocatalytic H2O2 production in pure water by 4.21-fold, which can be ascribed to that the SMSI simultaneously promotes the H2O dissociation and the photogenerated charge transfer from TiO2 to Pd catalyst, enabling highly efficient proton transfer to be participated into converting •O2- to H2O2. Moreover, the formation of TiO2-x overlayer caused by SMSI suppresses the H2O2 decomposition and stabilizes Pd NPs, finally achieving an H2O2 production rate of 4.10 mmol g−1 h−1, which surpasses most metal/TiO2 photocatalytic system.

Ultrafine Fe-Mn bimetallic nanoparticles anchored in nitrogen-doped carbon nanofiber electro-Fenton membrane with strong metal-support interactions for sustainable water decontamination in wide pH ranges

Designing a membrane electrode with high activity and anti-scaling ability in a wide pH range is crucial to the development of flow-through electro-Fenton system. Herein, we reported a novel porous membrane composed of ultrafine FeMn bimetallic nanoparticles anchored in nitrogen-doped carbon nanofibers (FeMn/N-CNF) obtained through a facile electrospinning-carbonization process. The strong metal-support interaction (SMSI) phenomena including carbon encapsulation structure and electron transfer from metal to N-CNF, beneficial to the intrinsic activities, were successfully induced by the enhanced interfacial metal-nitrogen bonding in FeMn/N-CNF. Microstructural characterizations and leaching test revealed that the SMSI encapsulation structure could promote the formation of ultrafine FeMn nanoparticles in N-CNF during the high-temperature carbonization process and prevent leaching of active Fe/Mn metals into solution across a wide pH range. The constructed gravity-driven flow-through electro-Fenton system based on a FeMn/N-CNF cathode membrane exhibited superior performance to generate H2O2 (36.23 mmol L−1 h−1) and subsequent activate H2O2 decomposition to hydroxyl radicals (0.1024 min−1), achieving remarkable degradation efficiencies of 96.8%, 92.3%, and 90.3% within 60 min for Rhodamine B, Tetracycline, and Methyl Orange, respectively. Furthermore, the FeMn/N-CNF membrane filter demonstrated good pH adaptability, excellent cycle stability and anti-scaling ability during the degradation process. This work offers a viable avenue to enhance degradation performance and environmental robustness for practical water decontamination via achieving SMSI effect in carbon-supported electro-Fenton membranes.

Stability enhancement of molybdenum modified rutile – carbon composite supported platinum electrocatalysts by reductive pretreatment: Surface characteristics and advanced electrocatalytic properties

Development of strong metal-support interaction (SMSI) and its influence on the catalytic performance of the Pt/Ti0.8Mo0.2O2-C system, a representative of the mixed oxide-carbon composite supported Pt electrocatalyst family, were investigated. Structural, surface chemical and electrochemical properties of the as-prepared Pt/Ti0.8Mo0.2O2-C catalyst and its counterparts reduced in the 150–450 °C temperature range were compared. TEM elemental mapping confirmed the widespread formation of Pt-oxide-C triple junctions in all catalysts. XPS revealed electronic interaction between the Pt particles and the oxide both in the as-prepared and the reduced catalysts, moreover, demonstrated that transport of Mo to the surface of Pt is initiated by reduction in the 150–250 °C range. Electrochemical measurements pointed out the durability of these Pt-bound Mo species, which also enhance the oxygen reduction activity of the catalyst. Based on the results of 10,000-cycle stability tests, reductive pretreatment between 250–350 °C is recommended for enhancing the properties of Pt/Ti0.8Mo0.2O2-C catalysts by SMSI.

In situ reaction-induced strong metal-support interaction to enhance catalytic performance and stability of toluene oxidation

The construction of strong metal-support interaction (SMSI) represents an attractive strategy to enhance the catalytic performance of the catalysts. Herein, the SMSI state over the Pt/TiO2 catalyst that inductively formed with a toluene atmosphere at a temperature below 300 °C is reported. During this process, the Pt species is covered by TiOx overlayers, while the Pt species is endowed to an electron-sufficient state, and more defects on the surface are produced simultaneously. Owing to the existence of formed SMSI, the interface of Pt and TiO2 with an improved redox property is conducive for oxygen species activation to expedite toluene conversion. The experimental results demonstrate that the catalysts with SMSI state exhibit improved catalytic activity and stability (5 vol% water and 800 °C thermal treatment). This work posits that the SMSI state of noble metal-supported catalysts can be dynamically produced during toluene conversion, which paves a novel method for designing efficient catalysts for the practical elimination of VOCs.

Strong metal-support interaction between Ni and BaCO3 boosts CO2 hydrogenation

Strong metal-support interaction between Ni and BaCO3 boosts CO2 hydrogenation

Thermally Stable Oxide-Capsulated Metal Nanoparticles Structure for Strong Metal-Support Interaction via Ultrafast Laser Plasmonic Nanowelding.

Strong metal-support interaction (SMSI) has drawn much attention in heterogeneous catalysts due to its stable and excellent catalytic efficiency. However, construction of high-performance oxide-capsulated metal nanostructures meets great challenge in materials thermodynamic compatibility. In this work, dynamically controlled formation of oxide-capsulated metal nanoparticles (NPs) structures is demonstrated by ultrafast laser plasmonic nanowelding. Under the strong localized electromagnetic field interaction, metal (Au) NPs are dragged by an optical force toward oxide NPs (TiO2). Intense energy is simultaneously injected into this heterojunction area, where TiO2 is precisely ablated. With the embedding of metal into oxide, optical force on Au gradually turned from attractive to repulsive due to the varied metal-dielectric environment. Meanwhile, local ablated oxides are redeposited on Au NP. Upon the whole coverage of metal NP, the implantation behavior of metal NP is stopped, resulting in a controlled metal-oxide eccentric structure with capsulated oxide layer thickness ≈0.72-1.30nm. These oxide-capsulated metal NPs structures can preserve their configurations even after thermal annealing in air at 600°C for 10min. This ultrafast laser plasmonic nanowelding can also extend to oxide-capsulated metal nanostructure fabrication with broad materials combinations (e.g., Au/ZnO, Au/MgO, etc.), which shows great potential in designing/constructing nanoscale high-performance catalysts.

Deciphering promotion of MoP over MoC in Pt catalysts for methanol-assisted water splitting reaction

Molybdenum-based compounds show promising promotion effects on Pt catalysts for energy-relevant catalysis reactions. Herein, a more effective promotion effect of MoP than MoC was found in assisting Pt nanoparticles for methanol-assisted hydrogen generation in light of the strong metal-support interaction and synergistic effect between Pt and MoP/C nanospheres. Electrochemical analyses and theoretical calculations demonstrated that Pt-MoP/C facilitated the oxidation and removal of CO intermediates more effectively than Pt-MoC/C. This enhanced performance was attributed to the distinct 6-coordination environment of hexagonal MoP and the elevated electron density of Mo induced by phosphorus. These structural and electronic features significantly enhanced electron transfer to Pt, thereby creating strong metal-support interaction and synergistic effect to improve the overall catalytic efficiency. Especially, the unique activities of Moδ+ and Moδ- in the MoP modified the surface structure of Pt, lowered the Pt d-band center, and optimized the local chemical state of Pt atoms, which resulted in more optimized adsorption energy and charge transfer capabilities of intermediates. The Pt-MoP/C electrolyzer thus showed both lower cell voltage than that of Pt-MoC/C and Pt/C electrolyzers in water splitting and methanol-assisted water splitting for hydrogen generation. This study offers insightful information about the promotion effect of molybdenum-based compounds in Pt catalyst systems in energy-relevant catalysis reactions.