Metal-support Interaction Effect Research Articles

Alloying Ni-Cu Nanoparticles Encapsulated in SiO2 Nanospheres for Synergistic Catalysts in CO2 Reforming with Methane Reaction.

In this work, we studied CO2 reforming with the methane (CRM) reaction over Ni-Cu alloy nanoparticles encapsulated in SiO2 nanospheres, for which combinational functions of alloy effect, size effect, metal-support interaction, and confinement effect exhibited high performance, good sintering resistance, and trace carbon deposition in CRM. The appropriate Cu-addition catalysts 0.2Cu-Ni@SiO2 and 0.5Cu-Ni@SiO2 had smaller NiCu alloy nanoparticles and a stronger metal-support interaction, exhibiting a better performance than the excessive Cu-addition catalysts 1.5Cu-Ni@SiO2 and 3Cu-Ni@SiO2 having Cu clusters and a weaker metal-support interaction. The best synergy of alloy effect, size effect, confinement effect, and metal-support interaction in the 0.5Cu-Ni@SiO2 catalyst contributed to the highest rates of CH4 and CO2 in CRM reported so far. This work demonstrates the importance of appropriate Cu addition in Ni-Cu@SiO2 catalysts, and the synergy for perfectly resolving sintering and carbon deposition in CRM.

Enhancement effect of strong metal-support interaction (SMSI) on the catalytic activity of substituted-hydroxyapatite supported Au clusters

Cation- and anion-substituted hydroxyapatites (sHAPs) supported gold catalysts showed strong metal-support interaction (SMSI) under oxidative atmosphere. Mg- and Ce-substituted sHAPs stabilized Au clusters and imparted positively charged Au. The Au on these sHAPs became more positively charged upon formation of the oxidative SMSI. The catalytic activities for transvinylation of benzoic acid with vinyl acetate and isomerization of 3,4-diacetoxybut-1-ene (34DABE) correlated well with the cationic properties of Au; Au/Mg0.1SrHAP and Au/Ce0.1SrHAP with SMSI exhibited higher catalytic activity than other Au/sHAPs and the same catalysts without SMSI. The enhanced cationic properties of Au particles induced by oxidative SMSI surpassed the disadvantages of the reduction of the exposed surface Au atoms caused by SMSI. This work reveals that controlling the degree of SMSI is an efficient methodology to tune an optimal electronic state of metal NPs for target reactions and to provide highly active and durable catalysts.

WO3 supported PtRu nanoalloys with tunable composition for enhancing catalytic activity

Creating a rational metal/metal oxide heterojunction represents an effective way to boost catalytic activity. Here, WO3/PtRu hybrid nanostructures were fabricated by depositing dendrite PtRu nanoalloys with tunable composition on WO3 nanosheets using the chemical reduction method. The WO3/PtRu hybrid nanostructures were characterized and investigated comprehensively for their multiple catalytic activities. Due to the strong metal-support interaction (SMSI) effect, WO3 nanosheets played critical roles in supporting PtRu nanoalloys with more active surface and facilitating electronic charge transfer, which can be used as active support to PtRu nanoalloys. As a result, WO3/Pt3Ru1 exhibits significantly higher catalytic activity than Pt3Ru1 to varying degrees for various catalytic reactions, including the oxidation of Fe2+ and the decomposition of H2O2, exhibiting enhanced oxidase-like (ferroxidase) and catalase-like activity, and reduction of 4-Nitrophenol (4-NP) in presence of NaBH4 and scavenging of DPPH free radicals. Furthermore, the activity is relied on the composition of PtRu nanoalloys but in distinct manner. The oxidase-like, catalase-like and DPPH scavenging activities showed similar order of WO3/Pt3Ru1 > Pt3Ru1 > WO3/Pt1Ru1 > WO3/Pt1Ru3, while 4-NP reduction activity order is WO3/Pt1Ru3 > WO3/Pt1Ru1 > Pt3Ru1 > WO3/Pt3Ru1. These results will be of value for efficient design of hybrid nanostructures with high performance and multiple functions.

Enhancement Effect of Strong Metal-Support Interaction (Smsi) on Catalytic Activity of Substituted-Hydroxyapatite Supported AU Clusters

Enhancement Effect of Strong Metal-Support Interaction (Smsi) on Catalytic Activity of Substituted-Hydroxyapatite Supported AU Clusters

Enhancing the Low-Temperature Co2 Methanation Over Ni/Zro2-Al2o3 Catalyst: The Effect of Strong Metal-Support Interactions and Changes in Active Site on the Catalytic Performance

Enhancing the Low-Temperature Co2 Methanation Over Ni/Zro2-Al2o3 Catalyst: The Effect of Strong Metal-Support Interactions and Changes in Active Site on the Catalytic Performance

High electrocatalytic activity of Pt on porous Nb-doped TiO2 nanoparticles prepared by aerosol-assisted self-assembly.

This study explores an aerosol-assisted method to prepare an efficient support for the Pt catalyst of polymer electrolyte membrane fuel cells (PEMFCs). Titania nanoparticles and mesoporous niobium-doped titania nanoparticles were prepared by aerosol-assisted self-assembly using titanium(iv) isopropoxide and niobium(v) ethoxide as the titanium and niobium sources for application as non-carbon supports for the platinum electrocatalyst. The structural characteristics and electrochemical properties of the supports were investigated by transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, electron paramagnetic resonance, inductively coupled plasma optical emission spectrometry, and dynamic light scattering. The Brunauer–Emmett–Teller method was used to calculate the specific surface areas of the samples, and the pore size distribution was also examined. The results demonstrated that under a radial concentration gradient, the aerosol droplets self-assembled into a spherical shape, and mesoporous supports were obtained after subsequent removal of the surfactant cetyltrimethylammonium bromide by annealing and washing. The hydrothermal technique was then used to deposit platinum on the TiO2-based supports. The electrical conductivity of the non-carbon support was enhanced by the strong metal–support interaction effect between the platinum catalyst particles and the porous niobium-doped TiO2 support. The half-wave potential, electrochemical surface area, mass activity, and specific activity of the obtained Pt/Nb-TiO2 catalyst all surpassed those of commercial Pt/C.

Improving Durability of Proton Exchange Membrane in Pemfc by Enhanced Radical Scavenging Performance of Pt@Ceo2 Via Strong Metal-Support Interaction Effect

Improving Durability of Proton Exchange Membrane in Pemfc by Enhanced Radical Scavenging Performance of Pt@Ceo2 Via Strong Metal-Support Interaction Effect

Polar bonds induced strong Pd-support electronic interaction drives remarkably enhanced oxygen reduction activity and stability

The strong metal-support interaction (SMSI) effect is attractive for improving the activity and durability of metal catalyst. Here, we uncovered that the strong polar bond in support can significantly boost the electrocatalytic oxygen reduction activity and durability of Pd nanoparticles (NPs). The mass-specific activity and surface-specific activity of optimized Pd/p-BNO at 0.90 V (vs.RHE) is almost 1.9 and 2.2 times higher than that of commercial Pt/C catalyst, respectively. By means of a joint experimental and computational study, the enhanced activity of Pd/p-BNO stems from the electron directly transfer through the strong polar OB bonds from support to Pd NPs leading to the electron-rich Pd surface. Moreover, the strong bonding effect of the caused by polarity bond effectively improves the stability of Pd/p-BNO. This progress demonstrates the vital role of polar chemical bonds in support on inducing SMSI effect, which might open up new opportunities in designing superior heterogeneous catalysts.

Fully exposed cobalt nanoclusters anchored on nitrogen-doped carbon synthesized by a host-guest strategy for semi-hydrogenation of phenylacetylene

Atomically dispersed nanocluster catalysts with fully available metal active sites can maximize atom utilization efficiency and deliver unique catalytic performance relative to nanoparticle and single-atom counterparts. Herein, we report a host–guest strategy by synergizing metal-support interaction and spatial confinement effect to access fully exposed cobalt nanoclusters over nitrogen-doped carbon as a highly active, selective, and reusable catalyst (Co loading of 1.6 wt%) for semi-hydrogenation of phenylacetylene. Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy, X-ray photoelectron spectroscopy, and CO-absorbed diffuse reflectance infrared Fourier transform spectroscopy collectively confirm the cobalt nanoclusters were loosely bonded and randomly dispersed over the nitrogen-doped carbon support. This catalyst, with a full metal availability to the reactants, shows an exceptional catalytic activity (turnover frequency of 3132 h−1) and selectivity (92%) in the semi-hydrogenation of phenylacetylene (1 atm H2@60 °C), superior to most of the previously reported catalysts. In addition, this catalyst exhibits a wide substrate scope and broad functional-group tolerance. This work may provide an avenue for the design and facile synthesis of fully exposed metal catalysts with high activity.

Fabrication of More Oxygen Vacancies and Depression of Encapsulation for Superior Catalysis in the Water-Gas Shift Reaction.

Fabrication of sufficient oxygen vacancies and exposure of active sites to reactants are two key factors to obtain high catalytic activity in the water-gas shift (WGS) reaction. However, these two factors are hard to satisfy spontaneously, since the formation of oxygen vacancies and encapsulation of metal nanoparticles are two inherent properties in reducible metal oxide supported catalysts due to the strong metal-support interaction (SMSI) effect. In this work, we find that addition of alkali to an anatase supported Ni catalyst (Ni/TiO2(A)) could well regulate the SMSI to achieve both more oxygen vacancies and depression of encapsulation; therefore, more than 20-fold enhancement in activity is obtained. It is found that the in situ formed titanate species on the catalyst surface is crucial to the formation of oxygen vacancies and depression of encapsulation. Furthermore, the methanation, a common side reaction of the WGS reaction, is successfully suppressed in the whole catalytic process.

New insights on the electronic factor of the SMSI effect in Pd/TiO2 nanoparticles

Whereas observed and explored for over 40 years, there are still open questions regarding the nature of the Strong Metal-Support Interaction (SMSI) effect. The lack of a precise determination of the atomic mechanisms of electronic and geometrical factors of the SMSI effect hinders the application of metal-support systems towards several catalytic reactions. The present study sheds light on the electronic factor of the SMSI effect in Pd/TiO2 nanoparticles by using Near Ambient Pressure Photoelectron Spectroscopy (NAP-XPS), Ultraviolet Photoelectron Spectroscopy (UPS), and Density Functional Theory (DFT) calculations. The electronic and geometrical factor of the SMSI effect were observed during reduction treatment at 300 °C and 500 °C, respectively. The results enable mapping the electronic factor during reduction treatment at 300 °C, where a charge transfer from Pd nanoparticles to TiO2 support through Pd-O-Ti entities existing at the Pd-TiO2 interface is observed. Furthermore, the charge transfer is mediated by O p states present at the Pd-TiO2 interface.

Hexagonal Boron Nitride Meeting Metal: A New Opportunity and Territory in Heterogeneous Catalysis.

Two dimensional (2D) hexagonal boron nitride (h-BN) has been ignored for a long time in catalysis research because of its chemical inertness. Recently there has been a significant advance highlighting the role of metal/h-BN interfaces in catalytic applications. In this Perspective, we summarize state-of-the-art progress regarding h-BN-involved metal catalysts. Vacancy- and defect-rich h-BN sheets are able to anchor and modify supported metals, in which the interfacial metal-support interaction effect helps to enhance catalytic performance. Oxidative etching of h-BN sheets causes encapsulation of metal catalysts via boron oxide (BOx) species, which work synergistically with neighboring metal sites in catalysis. Covering a metal surface with ultrathin h-BN shells creates a 2D nanoreactor featuring confinement effect, providing a novel way to modulate metal-catalyzed reactions. Given all those fascinating combinations of metal catalyst and h-BN, the emerging opportunity when h-BN meets metal in heterogeneous catalysis is clearly underlined. The outlook, especially the challenges in the field, are discussed as well.

Sacrificial Cu Layer Mediated the Formation of an Active and Stable Supported Iridium Oxygen Evolution Reaction Electrocatalyst.

The production of hydrogen via a proton-exchange membrane water electrolyzer (PEM-WE) is directly dependent on the rational design of electrocatalysts for the anodic oxygen evolution reaction (OER), which is the bottleneck of the process. Here, we present a smart design strategy for enhancing Ir utilization and stabilization. We showcase it on a catalyst, where Ir nanoparticles are efficiently anchored on a conductive support titanium oxynitride (TiONx) dispersed over carbon-based Ketjen Black and covered by a thin layer of copper (Ir/CuTiONx/C), which gets removed in the preconditioning step. Electrochemical OER activity, stability, and structural changes were compared to the Ir-based catalyst, where Ir nanoparticles without Cu are deposited on the same support (Ir/TiONx/C). To study the effect of the sacrificial less-noble metal layer on the catalytic performance of the synthesized material, characterization methods, namely X-ray powder diffraction, X-ray photoemission spectroscopy, and identical location transmission electron microscopy were employed and complemented with scanning flow cell coupled to an inductively coupled plasma mass spectrometer, which allowed studying the online dissolution during the catalytic reaction. Utilization of these advanced methods revealed that the sacrificial Cu layer positively affects both Ir OER mass activity and its durability, which was assessed via S-number, a recently reported stability metric. Improved activity of Cu analogue was ascribed to the higher surface area of smaller Ir nanoparticles, which are better stabilized through a strong metal–support interaction (SMSI) effect.

Creating High Regioselectivity by Electronic Metal-Support Interaction of a Single-Atomic-Site Catalyst.

Ligands are the most commonly used means to control the regioselectivity of organic reactions. It is very important to develop new regioselective control methods for organic synthesis. In this study, we designed and synthesized a single-atomic-site catalyst (SAC), namely, Cu1-TiC, with strong electronic metal-support interaction (EMSI) effects by studying various reaction mechanisms. π cloud back-donation to the alkyne on the metal catalytic intermediate was enhanced during the reaction by using transient electron-rich characteristics. In this way, the reaction achieved highly linear-E-type regioselective conversion of electronically unbiased alkynes and completely avoided the formation of branched isomers (ln:br >100:1, TON up to 612, 3 times higher than previously recorded). The structural elements of the SACs were designed following the requirements of the synthesis mechanism. Every element in the catalyst played an important role in the synthesis mechanism. This demonstrated that the EMSI, which is normally thought to be responsible for the improvement in catalytic efficiency and durability in heterogeneous catalysis, now first shows exciting potential for regulating the regioselectivity in homogeneous catalysis.

Highly dispersed Ni nanoparticles encapsulated in hollow mesoporous silica spheres as an efficient catalyst for quinoline hydrogenation

With the aim of studying the effect of support structure and preparation method on the hydrogenation performance of Ni-based catalysts. Hollow mesoporous silica spheres (hw-mSiO2) containing tiny Ni nanoparticles highly dispersed on the inner surface ([email protected]2) were synthesized by using carbon sphere as template with four continuous procedures, containing Ni deposition, silica shell coating, calcination and reduction. As demonstrated by SEM and TEM, the hollow structure was successfully obtained after calcination and the active Ni species was highly dispersed inside the porous silica shell, which is much smaller than the Ni-based catalysts prepared by a conventional impregnation method using hw-mSiO2 (Ni/hw-mSiO2) or commercial SiO2 (Ni/mSiO2) as supports. TPR and H2-chemisorption results revealed the existence of strong metal-interaction and more hydrogenation sites in [email protected]2. Therefore, [email protected]2 catalyst achieved an excellent catalytic activity and stability in the selective hydrogenation of quinoline into 1–4-tetrahydroquinoline (py-THQ), due to the more dispersed Ni species, strong metal-support interaction and confinement effect of porous silica shell.

Thermal coupled photocatalysis over Pt/g-C3N4 for selectively reducing CO2 to CH4via cooperation of the electronic metal–support interaction effect and the oxidation state of Pt

Pt nanoparticle-loaded g-C3N4 (Pt/CN) that consisted of integrating Pt0 and Pt2+ species was prepared for selectively reducing CO2 to CH4 with H2O by thermal coupled photocatalysis. A strong electronic metal-support interaction was constructed between Pt nanoparticles and the g-C3N4 substrate, which limited the activity for CO evolution and improved the charge transfer from g-C3N4 to Pt for selective CH4 production. The formed Pt2+ species in the Pt nanoparticles completely suppress the side reaction of H2 production from reducing H2O. Moreover, a moderate heat input in the photocatalytic reaction facilitated the transfer of the photogenerated electrons from Pt nanoparticles to CO2, which further increased the photocatalytic activity for CH4 evolution. As a result, a significant enhancement of CO2 methanation performance (∼100 % selectivity, 14.8 μmol g−1 h−1) was realized on a 2 % Pt-loaded g-C3N4 photocatalyst under low intensity light-emitting diode (420 nm, on the order of solar intensity) irradiation at 125 °C.

Single-atom Pt-I3 sites on all-inorganic Cs2SnI6 perovskite for efficient photocatalytic hydrogen production

Organic-inorganic lead halide perovskites are a new class of semiconductor materials with great potential in photocatalytic hydrogen production, however, their development is greatly plagued by their low photocatalytic activity, instability of organic component and lead toxicity in particular. Herein, we report an anti-dissolution environmentally friendly Cs2SnI6 perovskite anchored with a new class of atomically dispersed Pt-I3 species (PtSA/Cs2SnI6) for achieving the highly efficient photocatalytic hydrogen production in HI aqueous solution at room temperature. Particularly, we discover that Cs2SnI6 in PtSA/Cs2SnI6 has a greatly enhanced tolerance towards HI aqueous solution, which is very important for achieving excellent photocatalytic stability in perovskite-based HI splitting system. Remarkably, the PtSA/Cs2SnI6 catalyst shows a superb photocatalytic activity for hydrogen production with a record turnover frequency of 70.6 h−1per Pt, about 176.5 times greater than that of Pt nanoparticles supported Cs2SnI6 perovskite, along with superior cycling durability. Charge-carrier dynamics studies in combination with theory calculations reveal that the dramatically boosted photocatalytic performance on PtSA/Cs2SnI6 originates from both unique coordination structure and electronic property of Pt-I3 sites, and strong metal-support interaction effect that can not only greatly promote the charge separation and transfer, but also substantially reduce the energy barrier for hydrogen production. This work opens a new way for stimulating more research on perovskite composite materials for efficient hydrogen production.

Palladium nanoparticles anchored on Schiff base metal complex derived heteroatom-doped carbon materials for boosting ethanol electrooxidation

Designing appropriate support for noble metal-based catalyst has consistently been an effective strategy to improve the catalytic activity of ethanol electrooxidation reaction (EOR). Here, a novel heteroatom-doped carbon (HDC) material has been prepared by calcination of Schiff base metal complex precursor. The HDC-750 prepared at the optimum temperature (750 °C) has a three-dimensional structure with large specific surface area and unique pores. When the HDC-750 is used as a support for palladium nanoparticles, it can improve the conductivity of catalysts, the permeability of electrolyte and intermediates, and increase the number of anchoring points of palladium nanoparticles. Due to its unique three-dimensional structure and the synergistic enhancement effect of strong metal support interaction between Pd and HDC-750, the Pd/HDC-750 catalyst exhibits high electrochemical active surface area (23.94 m2 gPd−1) and excellent EOR activity (146.3 mA cm−2), which is as high as 2.1 and 3.0 times of that for the Pd/C. After 3600 s durability test, the Pd/HDC-750 shows a high current density of 9.9 mA cm−2, while Pd/C shows only 1.3 mA cm−2.

Boron Nanosheet-Supported Rh Catalysts for Hydrogen Evolution: A New Territory for the Strong Metal-Support Interaction Effect

HighlightsUltra-small and highly dispersed rhodium nanoparticles anchored in 2D ultra-thin boron nanosheets (BNS) were synthesized by a rapid NaBH4 reduction and facile freeze-dry approach.Due to the strong metal-support interaction effect, the optimized electrocatalyst exhibits excellent hydrogen evolution reaction (HER) catalytic activity and stability in the wide pH range electrolytes.Based on the stable surface, the oxidized boron surface facilitates the coupling of BNS and metal, giving catalyst outstanding HER performance.

The effects of SMSI on m-Cresol hydrodeoxygenation over Pt/Nb2O5 and Pt/TiO2

The hydrodeoxygenation (HDO) of m-cresol was studied on Pt/Nb2O5/MgAl2O4 and Pt/TiO2/MgAl2O4 catalysts to understand the effects of Strong Metal Support Interactions (SMSI). The Nb2O5 and TiO2 supports were prepared as 0.7-nm films on MgAl2O4 by Atomic Layer Deposition (ALD) to ensure that the structures of the catalyst were the same. When reduced at 773 K to place Pt in the encapsulated state, Pt/Nb2O5/MgAl2O4 was much less active than Pt/MgAl2O4 at 573 K but much more active at 623 K. While Pt/MgAl2O4 deactivated rapidly due to coking, Pt/Nb2O5/MgAl2O4 showed significantly better coke tolerance and was almost 100% selective towards toluene production. Pt/Nb2O5/MgAl2O4 reduced at lower temperatures exhibited intermediate catalytic properties. The effect of reduction temperature on Pt/TiO2/MgAl2O4 was much less and this catalyst was more similar to Pt/MgAl2O4 than its Nb2O5 counterpart. The implications of these results for understanding the nature of oxide promoters on HDO of m-cresol are discussed.