Strong Metal-support Interaction Effect Research Articles

Crystal Facet Controlled Metal-Support Interaction in Uricase Mimics for Highly Efficient Hyperuricemia Treatment.

The effect of strong metal-support interaction (SMSI) has never been systematically studied in the field of nanozyme-based catalysis before. Herein, by coupling two different Pd crystal facets with MnO2, i.e., (100) by Pd cube (Pdc) and (111) by Pd icosahedron (Pdi), we observed the reconstruction of Pd atomic structure within the Pd-MnO2 interface, with the reconstructed Pdc (100) facet more disordered than Pdi (111), verifying the existence of SMSI in such coupled system. The rearranged Pd atoms in the interface resulted in enhanced uricase-like catalytic activity, with Pdc@MnO2 demonstrating the best catalytic performance. Theoretical calculations suggested that a more disordered Pd interface led to stronger interactions with intermediates during the uricolytic process. In vitro cell experiments and in vivo therapy results demonstrated excellent biocompatibility, therapeutic effect, and biosafety for their potential hyperuricemia treatment. Our work provides a brand-new perspective for the design of highly efficient uricase-mimic catalysts.

Strong Interactions between Au Nanoparticles and BiVO4 Photoanode Boosts Hole Extraction for Photoelectrochemical Water Splitting.

Strong metal-support interaction (SMSI) is widely proposed as a key factor in tuning catalytic performances. Herein, the classical SMSI between Au nanoparticles (NPs) and BiVO4 (BVO) supports (Au/BVO-SMSI) is discovered and used innovatively for photoelectrochemical (PEC) water splitting. Owing to the SMSI, the electrons transfer from V4+ to Au NPs, leading to the formation of electron-rich Au species (Auδ-) and strong electronic interaction (i.e., Auδ--Ov-V4+), which readily contributes to extract photogenerated holes and promote charge separation. Benefitted from the SMSI effect, the as-prepared Au/BVO-SMSI photoanode exhibits a superior photocurrent density of 6.25 mA cm-2 at 1.23 V versus the reversible hydrogen electrode after the deposition of FeOOH/NiOOH cocatalysts. This work provides a pioneering view for extending SMSI effect to bimetal oxide supports for PEC water splitting, and guides the interfacial electronic and geometric structure modulation of photoanodes consisting of metal NPs and reducible oxides for improved solar energy conversion efficiency.

CO2 Conversion via Low-Temperature RWGS Enabled by Multicomponent Catalysts: Could Transition Metals Outperform Pt?

AbstractIn the context of CO2 valorisation, the reverse water–gas shift reaction (RWGS) is gathering momentum since it represents a direct route for CO2 reduction to CO. The endothermic nature of the reaction posses a challenge when it comes to process energy demand making necessary the design of effective low-temperature RWGS catalysts. Herein, multicomponent Cs-promoted Cu, Ni and Pt catalysts supported on TiO2 have been studied in the low-temperature RWGS. Cs resulted an efficient promoter affecting the redox properties of the different catalysts and favouring a strong metal-support interaction effect thus modulating the catalytic behaviour of the different systems. Positive impact of Cs is shown over the different catalysts and overall, it greatly benefits CO selectivity. For instance, Cs incorporation over Ni/TiO2 catalysts increased CO selectivity from 0 to almost 50%. Pt-based catalysts present the best activity/selectivity balance although CuCs/TiO2 catalyst present comparable catalytic activity to Pt-studied systems reaching commendable activity and CO selectivity levels, being an economically appealing alternative for this process.

Experimental and theoretical unraveling of the electrocatalytic hydrodechlorination of chlorinated phenol using Pd promoted by oxygen vacancies in TiO2 array

The electrocatalytic dichlorination (EHDC) shows a promising potential to degrade chlorinated phenols (CPs). It is also a green technology in reducing the corresponding hazardous impact on the environment. In this study, we constructed a catalytic structure which was Pd on a TiO2 array with oxygen vacancies on carbon fibre paper substrate (Pd/TiO2/CFP) by a relatively mild route. Due to the presence of the oxygen vacancies, the resulting strong metal-support interaction (SMSI) effect has been identified which featured a redistribution of spatial charge in Pd/TiO2. The electron flow from the oxygen vacancies in the TiO2 to Pd facilitated the adsorption of Pd with 4-chlorophenol (4-CP) and endowed the Pd metal with an improved chemical reaction kinetics even at a low Pd loading. Experimentally, we studied the dependence of pH, concentration of 4-CP, and working potential on the reaction conditions of EHDC. The results showed that the conversion of 4-CP reached 100 % within 180 min with an apparent rate constant of 2.9 × 10-2 min−1 and the dominant product was phenol (P). The multi-cycle test illustrated that the Pd/TiO2/CFP electrode showed superior stability. The results also revealed that the comprehensive catalytic behavior was much better than those of the Pd/CFP and the TiO2/CFP electrodes. The density function theory (DFT) calculations indicated that 4-CP was more preferably absorbed on Pd/TiO2/CFP than Pd/CFP due to the SMSI assistance. This study provides a valuable guide in the preparation of precious metal-based electrodes for EHDC with a reduced loading and cost but without performance compromise.

Research progress of metal oxide supports for fuel cells electrocatalysts

AbstractFuel cell technology, as a new way of energy conversion, is widely used in various fields. At present, the electrocatalyst, as one of the key components of the electrochemical reaction of fuel cells, still suffers from the problems of high cost, low activity and poor stability. Excellent fuel cell electrocatalysts must have excellent catalytic activity, anti‐poisoning ability, electrical conductivity and stability. Metal oxides with corrosion resistance, electrochemical stability and strong metal support interaction effects have been intensively studied. The influence of the synthesis method on the catalytic performance is also crucial. In this review, the importance of fuel cells and their catalysts is introduced. The characteristics of catalysts with three metal oxides, titanium dioxide, cerium dioxide and tungsten oxide, as supports, preparation methods and applications in different fuel cells are reviewed. The synthesis of metal oxide supported catalysts by impregnation, precipitation and hydrothermal methods is described. Finally, the research on metal oxide supported catalysts is prospected.

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.

TiO2 Nanolayer–Coated Carbon as Pt Support for Enhanced Methanol Oxidation Reaction

Abstract To facilitate the large-scale application of direct methanol fuel cells (DMFCs), the issue of low Pt/C durability due to Pt degradation and carbon corrosion in harsh DMFC operating conditions must be addressed. A promising strategy is to hybridize metal oxides with carbon materials, resulting in a durable and conductive support that exhibits a strong metal-support interaction (SMSI) effect on platinum nanoparticles (Pt NPs). In this study, we introduced a TiO2 coating on carbon black, creating a TiO2 nanolayer between Pt and carbon black. The nanolayer not only protects the carbon black but also activates the SMSI effect on Pt. The resulting Pt/C@TiO2 electrocatalyst exhibits superior durability than commercial Pt/C. After the accelerated durability test, the mass activity loss of the methanol oxidation reaction (MOR) of Pt/C@TiO2 (32%) is significantly lower than that of Pt/C (46.8%). Moreover, the MOR activity of Pt/C@TiO2 is higher than Pt/C as well. It suggests that Pt/C@TiO2 shows great potential as a highly durable and active electrocatalyst for DMFCs.

Construction of novel tandem reaction system coupling H2O2 production with in situ bleaching over Au/TiO2 photocatalyst with different metal-support interactions

A novel tandem reaction system formed with H2O2 production and in situ fabric bleaching reaction was firstly designed and constructed with Au/TiO2 photocatalyst. Results showed H2O2 generated in situ achieved high-efficiency fabric bleaching under the sunlight excitation, thus successfully constructing a ready-to-use system.·OH was confirmed as the main active specie in the simultaneous fabric bleaching reaction. Herein, to ensure the sufficient H2O2 production is a key factor. The different intensity of strong metal-support interaction (SMSI) was introduced into Au/TiO2 by regulating the calcination atmosphere to boost the H2O2 yield. H2/Ar calcination atmosphere imparted Au/TiO2 the SMSI effect to make H2O2 yield exceed that of counterpart under air atmosphere after 6 h of continuous reaction. The controllable capsulating overlayer on Au NPs provided relatively fewer exposed Au active sites to balance the H2O2 generation and decomposition rates, thus giving a better final yield. This work not only offer a novel path to improve H2O2 generation performance,but also propose new ideas for realizing in situ bleaching using sunlight as driving force and cleaning production of textile printing and dyeing industry.

Facile synthesis of surface oxygen vacancy and Ti3+ defects in SrTiO3 perovskite coupled g-C3N4 decorated with Au ternary nanocomposites for enhancing electrocatalytic activity from acidic and natural seawater conditions

The development of efficient electrocatalysts became vital to resolving the ongoing clean energy crises and environmental issues, wherein high-performance catalysts for the improved electrocatalytic hydrogen evolution reaction (EHER) are demanded. To meet this goal, an advanced and green ultrasonic-assisted pulsed laser ablation in liquid technique was used to prepare surface oxygen vacancy and Ti3+ defects in perovskite-based ternary nanocomposites (PTNCs) decorated with Au@SrTiO3/g-C3N4. An effective cathode was designed using Au@SrTiO3/g–C3N4–decorated PTNCs for EHER that operated in an acidic media of 0.5 M H2SO4. The optimized Au@SrTiO3/g-C3N4 PTNCs revealed an improved EHER at a very low over-potential of 0.082 V at a cathodic current density (J) of −10 mA/cm2, high double-layer capacitance (679.8 μF/cm2), large electrochemical surface area (19.4 cm2), high mass activity (198.35 A/g), high specific activity (2.91 mA/cm2), high surface charge density (0.0404 C/cm2), high catalytic active sites (4.19 × 10−7 mol/cm2), and exceptional long-term stability at 50 h, respectively. The Tafel slope of 45.36 mV/dec confirmed the presence of the Volmer-Heyrovsky mechanism to explain the enhanced EHER cycle of the prepared PTNCs. The improved electrocatalytic EHER performance was attributed to the induced synergistic strong metal-support interaction (SMSI) effect of the surface oxygen vacancy and Ti3+ defects in PTNCs that increased electrochemical surface area, high exposure of abundant active sites, improved intrinsic kinetics, and fast charge transport, respectively. Moreover, Au@SrTiO3/g–C3N4–decorated PTNCs exhibit excellent natural seawater electrolysis in terms of EHER at a low over-potential of 0.300 V at a J = −10 mA/cm2 and long-term stability at 10 h, respectively. It is demonstrated that the proposed novel surface oxygen vacancy and Ti3+ defects in Au@SrTiO3/g-C3N4 PTNCs are effective electrocatalysts can be beneficial for producing hydrogen from green technologies in future energy applications via interface engineering.

Modulating the strong metal-support interactions by regulating the chemical microenvironment of Pt confined in MOFs for low temperature hydrogenation of DCPD

Strong metal-support interaction (SMSI) plays an important role in heterogeneous catalysis, but the influence of the chemical microenvironment of metal on it is often neglected. In this study, a mesoporous Ce-MOFs with pyridine N sites and open metal sites (OMS) were constructed, and highly dispersed Pt nanoclusters (NCs) and Pt-Nx interface were subsequently introduced and constructed via SMSI effect for hydrogenation of dicyclopentadiene (DCPD). The spectroscopic results and density functional theory (DFT) computations demonstrate that pyridine N and OMS can regulate the SMSI effect between Ce-PyDC and Pt through Pt-Nx interface and electronic interaction between Pt and OMS, which increase electron cloud density of Pt nanoclusters, promote DCPD adsorption, H2 activation. The optimal Pt NCs@Ce-PyDC-3 can efficiently convert DCPD to tetrahydrodicyclopentadiene (THDCPD) at 50 °C, giving a 100 % DCPD conversion and 99 % THDCPD selectivity. This work provides an in-depth understanding of the correlation between the metal nanoparticle microenvironment and SISM effect.

Strong metal support interaction (SMSI) and MoO3 synergistic effect of Pt-based catalysts on the promotion of CO activity and sulfur resistance.

In industrial applications, Pt-based catalysts for CO oxidation have the dual challenges of CO self-poisoning and SO2 toxicity. This study used synthetic Keggin-type H3PMo12O40 (PMA) as the site of Pt, and the Pt-MoO3 produced by decomposition of PMA was anchored to TiO2 to construct the dual-interface structure of Pt-MoO3 and Pt-TiO2, abbreviated as Pt-P&M/TiO2. Pt-0.125P&M/TiO2 with a molar ratio of Pt to PMA of 8:1 showed both good CO oxidation activity and SO2 tolerance. In the CO activity test, the CO complete conversion temperature T100 of Pt-0.125P&M/TiO2 was 113 ℃ (compared with 135 ℃ for Pt/TiO2). In the SO2 resistance test, the conversion efficiency of Pt-0.125P&M/TiO2 at 170 ℃ remained at 60% after 72h, while that of Pt/TiO2 was only 13%. H2-TPR and XPS tests revealed that lattice oxygen provided by TiO2 and hydroxyl produced by MoO3 increased the CO reaction rate on Pt. According to the DFT theoretical calculation, the electronegative MoO3 attracted the d-orbital electrons of Pt, which reduced the adsorption energy of CO and SO2 from - 4.15eV and - 2.54eV to - 3.56eV and - 1.52eV, respectively, and further weakened the influence of strong CO adsorption and SO2 poisoning on the catalyst. This work explored the relationship between catalyst structure and catalyst performance and provided a feasible technical idea for the design of high-performance CO catalysts in industrial applications.

MgO impregnation to Al2O3 supported Ni catalyst for SYNGAS production using greenhouse gases: Some aspects of chemical state of Ni species

Al2O3 was prepared by sol–gel method and stabilized at 700 °C, then impregnated with 5, 15, and 30 wt% MgO to obtain the mixed oxide and stabilized again at 700 °C. The catalytic Ni/Al2O3 and Ni/Al2O3–MgO materials were prepared by impregnation method. The catalytic properties were studied on the dry reforming of methane (DRM) reaction using greenhouse gases (CO2+ CH4) to SYNGAS (Carbon Oxide/Hydrogen: CO/H2) at 700 °C for 70 h. The catalysts characterization includes TPR-H2, X-RD, BET, SEM, TPD-CO2, TPO-MS and TEM techniques. The CH4 and CO2 conversion was more stable in the Ni-base catalysts supported on mixed Al2O3–MgO oxides than in the Ni/Al2O3 sample. The Ni/Al2O3–MgO(5%) catalyst showed a lower presence of C (carbon) as evidenced by TPO-MS, XRD, SEM and TEM characterization. This finding reveals that a low quantity of MgO in the catalyst, delays the carbon development and may be associated with the basic character and a greater dispersion of this oxide on the surface of the alumina. In addition to the Ni–Mg–Al–O spinel formation, which enhanced the strong metal-support interaction (SMSI) effect between the support and the active phase. The Ni sintering of the catalysts after catalytic reaction is likely at the expenses of Ni–Al–O and MgNiO2 phases as was evidenced by XRD technique. The effect of the oxidation state of the active phase on the Ni/Al2O3–MgO (5%) sample had influence on the CO2 transformation, H2/CO ratio, basic sites, and stability in the C species.

Anti-sintering Ni-ZnO catalyst stabilized by a dual protection of SMSI and carbon for efficient RWGS reaction

Colloidal nanoparticles with uniform particle size distribution, tailored exposed facets, and controllable compositions appealed to broad interests in heterogeneous catalysis. Nevertheless, due to the strong attachment of capping agents to the nanoparticles, cleaning the nanoparticle surface without changing the size of nanoparticles remains a significant challenge. Herein, based on the double confinement of the strong metal-support interaction (SMSI) effect and carbon encapsulation, the well-stabilized Ni-ZnO-S3 catalyst was successfully synthesized. The size of Ni nanoparticles after calcination in the sequence of H2-N2 mixture, air, and H2-N2 mixture remained below 5 nm. Due to no significant size change in Ni nanoparticles, the prepared Ni-ZnO-S3 catalyst served well as model catalysts in the RWGS reaction, where the CO2 conversion and CO yield increased proportionally to the Ni loading weight. According to the result of in-situ FTIR, an associative mechanism of RWGS reaction over Ni-ZnO-S3 was also identified. Therefore, this dual protect strategy provides a potential solution for building highly anti-sintering catalysts based on the colloidal synthesis route.

Cobalt Stabilization through Mesopore Confinement on TiO2 Support for Fischer-Tropsch Reaction.

Cobalt supported on mesostructured TiO2 catalysts has been prepared by a wet-impregnation method. The Co/TiO2 catalytic system showed better catalytic performance after support calcination at 380 °C. Co nanoparticles appeared well distributed along the mesopore channels of TiO2. After reduction pretreatment and reaction, a drastic structural change leads to mesopore structure collapse and the dispersion of the Co nanoparticles on the external surface. Along this complex process, Co species first form discrete nanoparticles inside the pore and then diffuse out as the pore collapses. Through this confinement, a strong metal-support interaction effect is hindered, and highly stable metal active sites lead to better performance for Fischer-Tropsch synthesis reaction toward C5+ products.

Strong metal–support interaction boosts the electrocatalytic hydrogen evolution capability of Ru nanoparticles supported on titanium nitride

AbstractRuthenium (Ru) has been regarded as one of the most promising alternatives to substitute Pt for catalyzing alkaline hydrogen evolution reaction (HER), owing to its inherent high activity and being the cheapest platinum‐group metal. Herein, based on the idea of strong metal–support interaction (SMSI) regulation, Ru/TiN catalysts with different degrees of TiN overlayer over Ru nanoparticles were fabricated, which were applied to the alkaline electrolytic water. Characterizations reveal that the TiN overlayer would gradually encapsulate the Ru nanoparticles and induce more electron transfer from Ru nanoparticles to TiN support by the Ru–N–Ti bond as the SMSI degree increased. Further study shows that the exposed Ru–TiN interfaces greatly promote the H2 desorption capacity. Thus, the Ru/TiN‐300 with a moderate SMSI degree exhibits excellent HER performance, with an overpotential of 38 mV at 10 mA cm−2. Also, due to the encapsulation role of TiN overlayer on Ru nanoparticles, it displays super long‐term stability with a very slight potential change after 24 h. This study provides a deep insight into the influence of the SMSI effect between Ru and TiN on HER and offers a novel approach for preparing efficient and stable HER electrocatalysts through SMSI engineering.

Enhanced radical scavenging performance of Pt@CeO2 via strong metal-support interaction effect for improving durability of proton exchange membrane fuel cell

Since scavenging free radical is regarded as an efficient strategy to enhance the durability of proton exchange membrane fuel cells (PEMFCs), strong metal-support interaction (SMSI) effect between metal and reducible oxide supports is employed as a strategy to moderate the number of accessible active sites for reduction-oxidation reaction. Enriched Pt–CeO2 interface to enhance SMSI effect is achieved as well via constructing multicore-shell structure Pt@CeO2. Theoretical calculation confirms that SMSI effect at Pt–CeO2 interface endows electrons flowing from Pt to CeO2 to reduce the formation energy of oxygen vacancies, while Pt@CeO2 with higher magnitude of lattice distortion plan provides enriched Pt–CeO2 interface that made more concentration of Ce3+ ions feasible. Results show that better free radical scavenging performance is achieved with higher concentration of Ce3+ ions in Pt@CeO2. Based on the open circuit voltage (OCV) test, the Pt@CeO2-modified membrane in this work decays at only 70% of the commercial membrane, while 65% of the maximum power is still maintained after the test. This superior performance to the commercial membrane indicates this designed structure with SMSI effect could be considered as a potential route to solve the free radical problem in PEM for enhanced durability of PEMFCs.

Enhanced catalytic stability and structural evolution of Rh-BN interface in dry reforming of methane under intensified CO2 partial pressure

Strong metal-support interaction (SMSI) is a crucial factor that determines the structure and performance of a supported metal catalyst. Herein, the SMSI effect of Rh nanoparticle catalyst supported on h-BN is investigated in the dry reforming of methane (DRM) reactions with different CO2/CH4 ratios. The catalyst characterization results demonstrate that the SMSI effect allows the Rh nanoparticles to be encapsulated by BOx overlayers under DRM reaction conditions (CO2/CH4 = 1/1), which prevents the interaction between the reactants and metal centers for causing rapid deactivation. By increasing the partial pressure of CO2 (CO2/CH4 = 3/1), Rh/BN exhibits significantly enhanced activity and long-term stability in the DRM reaction. CO2 or H2O in the reactive atmosphere can effectively etch the BOx overlayers for steadily exposing the active Rh-BN interface sites, as evidenced by the characterization. This observation extends the understanding of the SMSI effect at the interfaces between metal and non-oxide support.

Boosting the catalysis of gold supported on perovskites by strong metal-support interaction

Gold catalysts show excellent selectivity in chemoselective hydrogenation reactions. However, their reactivity and stability are relatively inferior to Pt-group metal catalysts due to the moderate hydrogen activation and carbonaceous deposits. Herein, we reported that the strong metal-support interaction (SMSI) between gold nanoparticles and perovskites can increase the catalytic performance of gold-based catalysts in 3-nitrostyrene chemoselective hydrogenation reaction. HAADF-STEM elemental mapping images and line scan profiles confirmed that the oxide support can partially cover the surface of gold NPs, increasing the interfacial area between gold NPs and perovskites support. H2-D2 exchange reaction, reaction kinetic analysis and density functional theory calculations revealed that the apparent activation energy of 3-NS chemoselective hydrogenation reaction over gold supported on perovskites with SMSI effect was significantly decreased by the more facile H2 dissociation, 3-NS and its’ intermediate activation at the increased interface. This discovery of SMSI effect in Au and perovskites offers new insights into tuning performance of gold-based catalysts via changing the types of metal ions in perovskites.

SMSI-induced charge transfer for selective hydrogenolysis of polyolefins

The in-depth mechanism of the emerging Ru-catalyzed polyolefin hydrogenolysis remains unclear. Here, we overcome this challenge by constructing a strong metal-support interaction (SMSI) system based on Ru/TiO2 catalysts. With the increase of SMSI intensity, electrons are transferred from the TiOx capping layer to the Ru species. This effect facilitates the key steps of hydrogenation/desorption, while having little effect on the dehydrogenation and C–C cracking elementary reactions. As a result, the catalyst with higher hydrogenation capability prone to proceed hydrogenation and desorption step, thus suppressing cascade C–C cracking and avoiding the production of low value methane. The catalyst with the strongest SMSI effect exhibits a liquid fuel yield of 89.4% at ∼100% solid conversion. The SMSI effect also enables the catalysts with superior stability, so it can also efficiently upcycle commercial polyolefins. This work provides an in-depth understanding of the effects of metal-support interactions on polyolefin hydrogenolysis and paves the way for catalyst design.

The intriguing bifunctional effect of strong metal support interaction (SMSI) and hydrogen spillover effect (HSPE) for effective hydrogen evolution reaction

The mechanistic insights behind the kinetics of Hydrogen evolution reaction are unraveled through the bifunctional effect - Strong Metal Support Interaction (SMSI) and Hydrogen Spillover Effect (HSPE) on the WO3 hexagonal nanorods decorated with gold clusters and supported on the reduced graphene layers. The investigation is extended to scaling the electrocatalyst in a flexible electrode-carbon fiber for robust hydrogen evolution reaction in broad pH spectra. The research found that the proposed electrocatalyst demonstrated a reduced overpotential of 20 mV at a current density of 10 mA cm2 in acidic conditions and the stability of the ternary catalyst was verified through the Pourbaix profile. The Tafel slope was also comparable to that of the noble metal electrocatalyst Pt/C, with values of 35 mV dec–1 in 0.5 M H2SO4. The study demonstrated the potential for large-scale application of the proposed catalyst with stable operation observed for 24 h.