Showing papers on "Noble metal published in 2021"
TL;DR: In this paper, the authors highlight the significant role of noble metal doping in boosting water splitting electrocatalysis, and highlight the influence of metal doping on the electrocatalytic performance.
Abstract: Electrochemical water splitting has a promising future in producing high-density and green hydrogen, however, the sluggish H2O dissociation process, due to the low H2O adsorption on the catalyst surface, greatly hinders the industrial electrochemical water splitting on a large scale. Therefore, intensive efforts have been devoted to the exploration of efficient approaches for fabricating highly efficient electrocatalysts with appropriate H2O adsorption, such as defect engineering, interface engineering, and morphology design. Among them, metal doping, particularly noble metal (Ru, Rh, and Ir) doping, is essential to optimize the adsorption of reaction intermediates on the surface of catalysts, and has thus attracted increasing research interest. In order to uncover the significant role of noble metal doping in boosting water splitting electrocatalysis, this minireview showcases the most recent examples towards this endeavor, and begins by illustrating the mechanisms for water splitting and several advanced approaches for realizing noble metal doping. In the main text, we have also specifically highlighted the influences of noble metal doping on the electrocatalytic performance. Finally, some challenges and future outlooks are also presented to offer guidance for practical applications.
138 citations
TL;DR: In this paper, high performance 3d-5d transition metal (TM) SA catalysts using density functional theory (DFT) along with machine learning (ML)-based descriptors are evaluated for hydrogen evolution reaction (HER) and oxygen evolution/reduction reactions (OER/ORR).
Abstract: Noble nanoparticle (NP)-sized electrocatalysts have been exploited for diverse electrochemical reactions, in particular, for an eco-friendly hydrogen economy such as water splitting. Recently, minimal amounts of single atoms (SAs) are exploited to maximize the active surface area and to tune the catalytic activity by coordinating the SAs in defect sites of N-doped graphene (GN). For the hydrogen evolution reaction (HER) and oxygen evolution/reduction reactions (OER/ORR), we show high-performance 3d–5d transition metal (TM) SA catalysts using density functional theory (DFT) along with machine learning (ML)-based descriptors. We explore the stability and activity of TM–GN from the view of structure/coordination, formation energy, structural/electrochemical stability, electronic properties, electrical conductivity, and reaction mechanism, which have not been seriously explored yet. Among various –NnCm moieties, the –N2C2 moieties tend to be more easily formed and show higher electrochemical catalytic performance and longer durability (without aggregation/dissolution) compared with the widely studied pure –C4/C3 and –N4/N3 moieties. We found that some TM(SA)s favor a new OER/ORR mechanism, completely different from any known mechanism. The ML-based descriptors showing super HER/OER/ORR performances better than those of bench-mark noble metal catalysts are assessed. In the N2C2 templates, Ni/Ru/Rh/Pt show low HER overpotentials. Here, the H adsorption sites are shared by both the metal and C (not N), which was undiscussed in most of the previous literature where the H is attached on top of a metal atom. Low OER overpotentials are found for Pt/Ni–N2C2, Ni/Pd–C4, and Rh–N4, while low ORR overpotentials are found for Ir/Rh-N4, Pd–C4, Ru–N3C1 and Ni/Pd/Pt–N1C3. The present findings should help in designing high-performance SA catalysts for other various electrocatalytic reactions such as the ammonia evolution reaction.
128 citations
TL;DR: In this paper, Ni is atomically dispersed over α-MoC via carbon bridge bonds, forming a Ni1-Cx motif on the carbide surface, which can effectively stabilize the isolated Ni1 sites over the substrate, rendering maximized active site density and high structural stability.
Abstract: Methanol-water reforming is a promising solution for H2 production/transportation in stationary and mobile hydrogen applications. Developing inexpensive catalysts with sufficiently high activity, selectivity, and stability remains challenging. In this paper, nickel-supported over face-centered cubic (fcc) phase α-MoC has been discovered to exhibit extraordinary hydrogen production activity in the aqueous-phase methanol reforming reaction. Under optimized condition, the hydrogen production rate of 2% Ni/α-MoC is about 6 times higher than that of conventional noble metal 2% Pt/Al2O3 catalyst. We demonstrate that Ni is atomically dispersed over α-MoC via carbon bridge bonds, forming a Ni1-Cx motif on the carbide surface. Such Ni1-Cx motifs can effectively stabilize the isolated Ni1 sites over the α-MoC substrate, rendering maximized active site density and high structural stability. In addition, the synergy between Ni1-Cx motif and α-MoC produces an active interfacial structure for water dissociation, methanol activation, and successive reforming processes with compatible activity.
112 citations
TL;DR: In this article, a 3 × 3 gas sensor array with and without Au nanoparticle (NP) decorating was used for indoor air quality monitoring, and the results revealed that the dominant enhancement mechanism of Au NPs for each combination of gases and metal oxide is a decrease in activation energy.
Abstract: With the increasing demands of indoor air quality monitoring, highly sensitive and selective gas sensor arrays consisting of metal oxide semiconductors have been increasingly studied. As an effective strategy to obtain the desired performance, noble metal functionalization is frequently chosen owing to its target-specific sensing mechanisms. However, the lack of a comprehensive analysis on the sensing mechanisms of different combinations of metal oxides and noble metals limit the versatility of these sensor arrays for use in selective gas sensor arrays. In this study, we fabricate a 3 × 3 gas sensor array to obtain a reliable comparison of the sensing mechanism through the use of three metal oxides—WO3, SnO2 and NiO—in three different nanostructure forms: a thin film and dome-like nanostructures with and without Au nanoparticle (NP) decoration. The responses of the sensor arrays to four target gases (CH3COCH3, C6H5CH3, NH3, and H2S) are generally enhanced by the dome-like nanostructure and show distinctively enhanced responses when the sensors are decorated with Au NPs. Moreover, the dome-like SnO2 with Au NPs shows an increase of up to 121 times for C6H5CH3 compared with the pristine SnO2 thin film. Additionally, the sensitization effects of Au NPs depend on the types of metal oxides and gases, which improve the gas discrimination capability by diversifying the gas selectivity of the sensor units in the array. The prepared sensor array can distinguish four target gases by principal component analysis (PCA). The contributions of different enhancement mechanisms, which are dependent on the gases and metal oxides, are investigated by comparing the activation energy of each gas response with and without Au. The comparison among the chosen gases reveals that the decoration of Au NPs is effective for C6H5CH3 and NH3 regardless of the type of metal oxide. Among the metal oxides, the effects of Au NPs on gas responses are in the order of SnO2, NiO, and WO3, in which the energy level difference between the Au NPs and metal oxide are 0.2, 0.1, and −0.6 eV, respectively. These results confirm that the dominant enhancement mechanism of Au NPs for each combination of gases and metal oxide is a decrease in activation energy. Therefore, this study provides a systematic understanding of the sensitization mechanism of Au NPs on metal oxides toward gases for the fabrication of selective gas sensor arrays.
107 citations
TL;DR: In this article, the authors demonstrate a highly-durable alloy catalyst derived by alloying PtPd with 3D transition metals (Cu, Ni or Co) in ternary compositions, and the origin of the high durability is probed by in-situ/operando high-energy synchrotron X-ray diffraction coupled with pair distribution function analysis of atomic phase structures and strains.
Abstract: Alloying noble metals with non-noble metals enables high activity while reducing the cost of electrocatalysts in fuel cells. However, under fuel cell operating conditions, state-of-the-art oxygen reduction reaction alloy catalysts either feature high atomic percentages of noble metals (>70%) with limited durability or show poor durability when lower percentages of noble metals (<50%) are used. Here, we demonstrate a highly-durable alloy catalyst derived by alloying PtPd (<50%) with 3d-transition metals (Cu, Ni or Co) in ternary compositions. The origin of the high durability is probed by in-situ/operando high-energy synchrotron X-ray diffraction coupled with pair distribution function analysis of atomic phase structures and strains, revealing an important role of realloying in the compressively-strained single-phase alloy state despite the occurrence of dealloying. The implication of the finding, a striking departure from previous perceptions of phase-segregated noble metal skin or complete dealloying of non-noble metals, is the fulfilling of the promise of alloy catalysts for mass commercialization of fuel cells.
106 citations
TL;DR: In this article, the process of glucose oxidation catalyzed by gold nanoparticles is shown to be similar to that of natural glucose oxidase, namely, a two-step reaction including the dehydrogenation of glucose and the subsequent reduction of O2 to H2O2 by two electrons.
Abstract: Au nanoparticles (NPs) have been found to be excellent glucose oxidase mimics, while the catalytic processes have rarely been studied. Here, we reveal that the process of glucose oxidation catalyzed by Au NPs is as the same as that of natural glucose oxidase, namely, a two-step reaction including the dehydrogenation of glucose and the subsequent reduction of O2 to H2O2 by two electrons. Pt, Pd, Ru, Rh, and Ir NPs can also catalyze the dehydrogenation of glucose, except that O2 is preferably reduced to H2O. By the electron transfer feature of noble metal NPs, we overcame the limitation that H2O2 must be produced in the traditional two-step glucose assay and realize the rapid colorimetric detections of glucose. Inspired by the electron transport pathway in the catalytic process of natural enzymes, noble metal NPs have also been found to mimic various enzymatic electron transfer reactions including cytochrome c, coenzymes as well as nitrobenzene reductions. Gold nanoparticles (Au NPs) with enzyme-like activities are useful glucose oxidase mimics, but the insights into the mechanism of this reaction are limited. Here, the authors show that the process of glucose oxidation by Au NPs is analogous to the one catalysed by glucose oxidase, involving dehydrogenation and oxygen reduction to H2O2; and that other noble metal NPs also catalyse glucose dehydrogenation, but oxygen is preferably reduced to water.
102 citations
TL;DR: A minireview describes the recent advances in hydrosilylation reactions using catalysts based on earth‐abundant transition metals, for example, Fe, Co, Ni, and Mn, and heterogeneous catalysts (supported nanoparticles and single‐atom sites) are noteworthy.
Abstract: Hydrosilylation reactions, which allow the addition of Si-H to C=C/C≡C bonds, are typically catalyzed by homogeneous noble metal catalysts (Pt, Rh, Ir, and Ru). Although excellent activity and selectivity can be obtained, the price, purification, and metal residues of these precious catalysts are problems in the silicone industry. Thus, a strong interest in more sustainable catalysts and for more economic processes exists. In this respect, recently disclosed hydrosilylations using catalysts based on earth-abundant transition metals, for example, Fe, Co, Ni, and Mn, and heterogeneous catalysts (supported nanoparticles and single-atom sites) are noteworthy. This minireview describes the recent advances in this field.
101 citations
TL;DR: The latest progress in understanding and exploiting the molecular interactions/reactions of noble metal NCs in their synthesis, self-assembly and application scenarios, based on the typical M(0)@M(i)–SR core–shell structure scheme, where M and SR are the metal atom and thiolate ligand, respectively.
Abstract: Thiolate-protected noble metal (e.g., Au and Ag) nanoclusters (NCs) are ultra-small particles with a core size of less than 3 nm. Due to the strong quantum confinement effects and diverse atomic packing modes in this ultra-small size regime, noble metal NCs exhibit numerous molecule-like optical, magnetic, and electronic properties, making them an emerging family of "metallic molecules". Based on such molecule-like structures and properties, an individual noble metal NC behaves as a molecular entity in many chemical reactions, and exhibits structurally sensitive molecular reactivity to various ions, molecules, and other metal NCs. Although this molecular reactivity determines the application of NCs in various fields such as sensors, biomedicine, and catalysis, there is still a lack of systematic summary of the molecular interaction/reaction fundamentals of noble metal NCs at the molecular and atomic levels in the current literature. Here, we discuss the latest progress in understanding and exploiting the molecular interactions/reactions of noble metal NCs in their synthesis, self-assembly and application scenarios, based on the typical M(0)@M(i)-SR core-shell structure scheme, where M and SR are the metal atom and thiolate ligand, respectively. In particular, the continuous development of synthesis and characterization techniques has enabled noble metal NCs to be produced with molecular purity and atomically precise structural resolution. Such molecular purity and atomically precise structure, coupled with the great help of theoretical calculations, have revealed the active sites in various structural hierarchies of noble metal NCs (e.g., M(0) core, M-S interface, and SR ligand) for their molecular interactions/reactions. The anatomy of such molecular interactions/reactions of noble metal NCs in synthesis, self-assembly, and applications (e.g., sensors, biomedicine, and catalysis) constitutes another center of our discussion. The basis and practicality of the molecular interactions/reactions of noble metal NCs exemplified in this Review may increase the acceptance of metal NCs in various fields.
94 citations
TL;DR: In this article, a torsion-strained Ta0.1Tm0.8O2-δ nanocatalyst with numerous grain boundaries was presented, which exhibited a low overpotential of 198 mV at 10 mA cm-2 towards oxygen evolution reaction in 0.5 M H2SO4.
Abstract: Acidic oxygen evolution reaction is crucial for practical proton exchange membrane water splitting electrolysers, which have been hindered by the high catalytic overpotential and high loading of noble metal catalysts. Here we present a torsion-strained Ta0.1Tm0.1Ir0.8O2-δ nanocatalyst with numerous grain boundaries that exhibit a low overpotential of 198 mV at 10 mA cm-2 towards oxygen evolution reaction in 0.5 M H2SO4. Microstructural analyses, X-ray absorption spectroscopy and theoretical calculations reveal that the synergistic effects between grain boundaries that result in torsion-strained Ir-O bonds and the doping induced ligand effect collectively tune the adsorption energy of oxygen intermediates, thus enhancing the catalytic activity. A proton exchange membrane electrolyser using a Ta0.1Tm0.1Ir0.8O2-δ nanocatalyst with a low mass loading of 0.2 mg cm-2 can operate stably at 1.5 A cm-2 for 500 hours with an estimated cost of US$1 per kilogram of H2, which is much lower than the target (US$2 per kg of H2) set by the US Department of Energy.
92 citations
TL;DR: In this article, a method of pulse laser ablation was used to generate Lychee-shaped morphology of RuO2 nanoparticles, and the surface tension induced by the lychee morphology improved the OER performance.
87 citations
TL;DR: In this article, a photo-assisted synthesis of novel g-C3N4/Co3O4/MoS2 heterojunction with low-cost Co 3O4 (oxidation) and MoS2 (reduction) cocatalyst separately deposited onto G-C 3N4 nanosheets is reported.
Abstract: The dual cocatalysts photocatalytic heterostructures are beneficial for water splitting. Here we report a simple photo-assisted synthesis of novel g-C3N4/Co3O4/MoS2 heterojunction with low-cost Co3O4 (oxidation) and MoS2 (reduction) cocatalyst separately deposited onto g-C3N4 nanosheets. Driven by the synergy between Co3O4 and MoS2, the photocatalytic H2 evolution (PHE) activity of g-C3N4/Co3O4-1.9/MoS2-0.9 under visible light irradiation is about 885, 25.6 and 18.2 times better than those for g-C3N4, g-C3N4/Co3O4-1.9 and g-C3N4/MoS2-0.9, respectively, and is also higher than those of g-C3N4 based heterojunctions decorated by MoS2, dual MoS2- and other metal sulfides-based cocatalysts. The g-C3N4/Co3O4-1.9/MoS2-0.9 exhibits stable PHE in the recycle experiment and in various real water matrices. Detail characterization reveals that rapid electron-hole separation and charge species transferring through both Z-scheme and Type-I routes contribute to the improved PHE. With this synthetic strategy, the reduction cocatalyst can be extended to NiS (CoS), and the acquired g-C3N4/Co3O4-1.9/NiS (CoS) also possesses synergistically efficient PHE.
TL;DR: In this paper, the authors show that atomically dispersed Pt-N3C1 sites planted on nitrogen-doped carbon nanotubes (Pt1/N-CNTs), constructed via a stepwise polymerization-carbonization-electrostatic adsorption strategy, are highly active and selective toward Cα-Cβ bond cleavage in β-O-4 model compounds under ambient conditions.
Abstract: Selective cleavage of C-C linkages is the key and a challenge for lignin degradation to harvest value-added aromatic compounds. To this end, electrocatalytic oxidation presents a promising technique by virtue of mild reaction conditions and strong sustainability. However, the existing electrocatalysts (traditional bulk metal and metal oxides) for C-C bond oxidative cleavage suffer from poor selectivity and low product yields. We show for the first time that atomically dispersed Pt-N3C1 sites planted on nitrogen-doped carbon nanotubes (Pt1/N-CNTs), constructed via a stepwise polymerization-carbonization-electrostatic adsorption strategy, are highly active and selective toward Cα-Cβ bond cleavage in β-O-4 model compounds under ambient conditions. Pt1/N-CNTs exhibits 99% substrate conversion with 81% yield of benzaldehyde, which is exceptional and unprecedented compared with previously reported electrocatalysts. Moreover, Pt1/N-CNTs using only 0.41 wt % Pt achieved a much higher benzaldehyde yield than those of the state-of-the-art bulk Pt electrode (100 wt % Pt) and commercial Pt/C catalyst (20 wt % Pt). Systematic experimental investigation together with density functional theory (DFT) calculation suggests that the superior performance of Pt1/N-CNTs arises from the atomically dispersed Pt-N3C1 sites facilitating the formation of a key Cβ radical intermediate, further inducing a radical/radical cross-coupling path to break the Cα-Cβ bond. This work opens up opportunities in lignin valorization via a green and sustainable electrochemical route with ultralow noble metal usage.
TL;DR: In this paper, a multidirectional charge transfer concept has been adopted within heterostructured catalysts to develop an efficient and robust bifunctional water electrolysis catalyst, which comprises perovskite oxides (La 0.5Sr0.5CoO3−δ, LSC) and potassium ion-bonded MoSe2 (K-MoSe2).
Abstract: The operating principle of conventional water electrolysis using heterogenous catalysts has been primarily focused on the unidirectional charge transfer within the heterostructure. Herein, multidirectional charge transfer concept has been adopted within heterostructured catalysts to develop an efficient and robust bifunctional water electrolysis catalyst, which comprises perovskite oxides (La0.5Sr0.5CoO3–δ, LSC) and potassium ion-bonded MoSe2 (K-MoSe2). The complementary charge transfer from LSC and K to MoSe2 endows MoSe2 with the electron-rich surface and increased electrical conductivity, which improves the hydrogen evolution reaction (HER) kinetics. Excellent oxygen evolution reaction (OER) kinetics of LSC/K-MoSe2 is also achieved, surpassing that of the noble metal (IrO2), attributed to the enhanced adsorption capability of surface-based oxygen intermediates of the heterostructure. Consequently, the water electrolysis efficiency of LSC/K-MoSe2 exceeds the performance of the state-of-the-art Pt/C||IrO2 couple. Furthermore, LSC/K-MoSe2 exhibits remarkable chronopotentiometric stability over 2,500 h under a high current density of 100 mA cm−2. While water electrolysis offers a renewable means to obtain H2, it is necessary to understand the roles adopted by catalytic components. Here, authors explore a heterostructured MoSe2/perovskite oxide catalyst that shows multidirectional charge transfer to boost electrocatalytic water splitting.
TL;DR: In this paper, highly dispersed Ru-Cu alloy nanoparticles were successfully fabricated via solid-surfaces-organic pyrolysis on N-doped carbon coating TiO2 towards hydrogen evolution in NH3BH3 hydrolysis.
Abstract: The development of high-efficient and economical catalysts is a challenging problem for the utilization of sustainable hydrogen energy. Alloying noble metal with non-noble metal is a promising strategy to achieve high catalytic activity and stability of catalysts. Herein, highly dispersed Ru-Cu alloy nanoparticles were successfully fabricated via solid-surfaces-organic-pyrolysis on N-doped carbon coating TiO2 towards hydrogen evolution in NH3BH3 hydrolysis. Ru-Cu alloys with various molar ratios exhibit markedly enhanced catalytic activity than monometallic counterparts. The optimized Ru0.6Cu0.4/TiO2@C-N catalyst achieves an excellent TOF of 626 molH2 molRu−1 min−1 at room temperature. Experimental analysis and DFT calculation reveal the existence of ensemble-boosting effect between Ru and Cu. Multiatomic active sites in alloy significantly promote hydrogen evolution in NH3BH3 hydrolysis. This research provides further understanding of catalytic mechanism and the rational design of high-efficient and economical bimetallic nanocatalysts.
TL;DR: In this paper, the influence of noble metal interlay doping on the catalytic hydrogen evolution activity of 2H-MoS2 was investigated, and it was found that the Ru-doped Ru-4d state from low energy region to high energy region, which weakens the interaction between Mo and S, has better thermodynamic stability.
TL;DR: The roles of noble metals on ceria with respect to catalytic activity revealed the improved soot oxidation activity, with an enhanced ability to generate oxygen vacancy formation and oxygen adsorption and increased electron transfer.
TL;DR: A new chiral pincer manganese catalyst showed outstanding catalytic activity in the asymmetric hydrogenation of quinolines, affording high yields and enantioselectivities, and was competitive with the activity of most effective noble metal catalysts for this reaction.
Abstract: The first example of non-noble metal-catalyzed asymmetric hydrogenation of N-heteroaromatics is reported. A new chiral pincer manganese catalyst showed outstanding catalytic activity in the asymmetric hydrogenation of quinolines, affording high yields and enantioselectivities (up to 97% ee). A turnover number of 3840 was reached at a low catalyst loading (S/C=4000), which was competitive with the activity of most effective noble metal catalysts for this reaction. The precise regulation of the enantioselectivity were ensured by a π-π interaction.
TL;DR: In this article, bifunctional electrocatalysts for ORR and OER were designed and constructed for high performance rechargeable metal-air battering for both the ORR reaction and the OER reaction.
Abstract: Designing and fabricating bifunctional electrocatalysts for both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is crucial to high-performance rechargeable metal–air batter...
TL;DR: The transition metal-based catalysts are more appealing than the noble metal catalysts because of its low cost, high performance, and long stability as mentioned in this paper, however, the urgent challenge in water electrolysis is to search for low-cost, high-efficiency catalysts based on earth-abundant elements as an alternative to the high-cost but effective noble metal based catalysts.
TL;DR: In this article, a facile one-pot hydrothermal procedure for the photocatalytic H2 evolution from water splitting has been developed to facilitate the highly efficient synergistic effect between co-catalyst and heterostructure.
TL;DR: Cucurbiturils, a class of synthetic macrocycles with intriguing and peculiar host-guest properties, have stimulated tremendous research interest in recent years as discussed by the authors, which is expected to integrate and enhance the excellent characteristics of both components, e.g., precisely controlled particle size, stability, assembly, surface functionality, biocompatibility, tunable optical properties, and high catalytic activities.
Abstract: Noble metal nanoparticles (NMNPs), which spring up like mushrooms, are gaining momentum owing to their unique physicochemical characteristics. Cucurbiturils, a class of synthetic macrocycles with intriguing and peculiar host–guest properties, have stimulated tremendous research interest in recent years. The marriage of NMNPs with cucurbiturils is expected to integrate and enhance the excellent characteristics of both components, e.g., precisely controlled particle size, stability, assembly, surface functionality, biocompatibility, tunable optical properties, and high catalytic activities. This review systematically outlines the recent progress on the fabricating strategies and important applications of cucurbiturils-mediated NMNPs in sensing, surface-enhanced Raman scattering, theranostics, and catalysis. A brief outlook on the future development of cucurbiturils-mediated NMNPs is also presented.
TL;DR: In this article, the authors reported that the Cu1/ZSM-5 single atom catalyst is highly active (C1 oxygenates productivity of 4800 μmol⋅gcat−1 at 50 °C and 12,000 μmol−1 within 30 min) and selective (C 1 oxygenates selectivity of 99 % at 50°C) for direct CH4 oxidation, comparable to most of those state of the art noble metal catalysts.
Abstract: Catalytically converting CH4 to chemicals and fuels is of paramount importance but remains a major challenge to simultaneously obtain high activity and selectivity. Here, we report Cu1/ZSM-5 single atom catalyst is highly active (C1 oxygenates productivity of 4800 μmol⋅gcat−1 at 50 °C and 12,000 μmol⋅gcat-1 at 70 °C within 30 min) and selective (C1 oxygenates selectivity of 99 % at 50 °C) for direct CH4 oxidation, comparable to most of those state-of-the-art noble metal catalysts. The combined DFT calculation, electronic microscope, X-ray absorption and electron paramagnetic resonance results confirm that each isolated Cu atom stabilized by four O moieties on the ZSM-5 support possesses uniform Cu1-O4 entity as active site and preferentially activates CH4 instead of CH3OH that is advantageous for highly selective C1 oxygenates production, especially for methanol. Our molecular-level finding on the atomic structure of Cu active site paves the way to design better catalysts for methane conversion.
TL;DR: In this paper, a non-noble-metal catalyst was designed and synthesized for ammonia borane (NH3BH3, AB) hydrolysis.
TL;DR: In this article, the formulation and periodic self-assembly of different noble metal nanoclusters are focused upon, and their potential applications in molecular recognition, sensing, gas storage, device fabrication, bioimaging, therapeutics, and catalysis are discussed.
Abstract: Ligand protected noble metal nanoparticles are excellent building blocks for colloidal self-assembly. Metal nanoparticle self-assembly offers routes for a wide range of multifunctional nanomaterials with enhanced optoelectronic properties. The emergence of atomically precise monolayer thiol-protected noble metal nanoclusters has overcome numerous challenges such as uncontrolled aggregation, polydispersity, and directionalities faced in plasmonic nanoparticle self-assemblies. Because of their well-defined molecular compositions, enhanced stability, and diverse surface functionalities, nanoclusters offer an excellent platform for developing colloidal superstructures via the self-assembly driven by surface ligands and metal cores. More importantly, recent reports have also revealed the hierarchical structural complexity of several nanoclusters. In this review, the formulation and periodic self-assembly of different noble metal nanoclusters are focused upon. Further, self-assembly induced amplification of physicochemical properties, and their potential applications in molecular recognition, sensing, gas storage, device fabrication, bioimaging, therapeutics, and catalysis are discussed. The topics covered in this review are extensively associated with state-of-the-art achievements in the field of precision noble metal nanoclusters.
TL;DR: In this paper, it was shown that at applied bias, NiMoO4·H2O transforms into γ-NiOOH, which is a promising noble metal free catalyst for the oxygen evolution reaction.
Abstract: Water electrolysis powered by renewable energies is a promising technology to produce sustainable fossil free fuels. The development and evaluation of effective catalysts are here imperative; however, due to the inclusion of elements with different redox properties and reactivity, these materials undergo dynamical changes and phase transformations during the reaction conditions. NiMoO4 is currently investigated among other metal oxides as a promising noble metal free catalyst for the oxygen evolution reaction. Here we show that at applied bias, NiMoO4·H2O transforms into γ-NiOOH. Time resolved operando Raman spectroscopy is utilized to follow the potential dependent phase transformation and is collaborated with elemental analysis of the electrolyte, confirming that molybdenum leaches out from the as-synthesized NiMoO4·H2O. Molybdenum leaching increases the surface coverage of exposed nickel sites, and this in combination with the formation of γ-NiOOH enlarges the amount of active sites of the catalyst, leading to high current densities. Additionally, we discovered different NiMoO4 nanostructures, nanoflowers, and nanorods, for which the relative ratio can be influenced by the heating ramp during the synthesis. With selective molybdenum etching we were able to assign the varying X-ray diffraction (XRD) pattern as well as Raman vibrations unambiguously to the two nanostructures, which were revealed to exhibit different stabilities in alkaline media by time-resolved in situ and operando Raman spectroscopy. We advocate that a similar approach can beneficially be applied to many other catalysts, unveiling their structural integrity, characterize the dynamic surface reformulation, and resolve any ambiguities in interpretations of the active catalyst phase.
TL;DR: In this paper, the influence of noble metals on the electronic and optical properties of LiH hydride was investigated and it was found that only the Pt-doped LiH is a dynamical stability compared to the other noble metals doping.
TL;DR: In this paper, a hierarchical porous carbon microspheres with a trace amount of encapsulated cobalt as highly active and stable electrocatalysts for the ORR under wide pH values ranged from high alkaline to high acidic conditions.
TL;DR: Recently, nanotechnology has emerged as a tool for the development in the biological synthesis of noble metal nanoparticles as discussed by the authors. Among other conventional synthesis methods, biological synthesis methods have been used in the development of noble metals nanoparticles.
Abstract: Recently, nanotechnology has emerged as a tool for the development in the biological synthesis of noble metal nanoparticles. Among other conventional synthesis methods, biological synthesis methods...
TL;DR: The metal oxides have been extensively used as supports in noble metal-based catalysts for formaldehyde (HCHO) oxidation, utilizing the benefit of the strong metal-support interaction (SMSI) as discussed by the authors.
Abstract: Metal oxides have been extensively used as supports in noble metal-based catalysts for formaldehyde (HCHO) oxidation, utilizing the benefit of the strong metal–support interaction (SMSI). Non-oxide...
TL;DR: In this article, the authors demonstrated the efficient charge separation and migration at zinc oxide nanostars (ZnONSt) via conjugation with noble metal nanoparticles (MNP = Ag, Pd) and its application in degradation of carcinogenic pesticides and herbicides.