Noble Metal Loading Research Articles

High-efficiency mass-transfer Marangoni cellulose hydrogel reactor for the degradation of pollutants.

Noble metal nanoparticles have been widely used in catalysis, environmental studies, and other fields. However, the loading of noble metals is challenging because of their unfavorable mass transfer. Herein, a simple, green dual-template method was developed for the synthesis of a Marangoni cellulose hydrogel rotor catalytic reactor (MCR). The rotor had a two-component asymmetrical network structure, which was constructed via different crosslinking methods and enabled the MCR to achieve a fast (6190 r/h) and prolonged (25 min) rotation. In addition, we propose a new refueling method, which only requires 80uL solvent to continue to drive the rotor for over 13 min, effectively prolonging the rotation time of the rotor. During rotation, the speed of the catalyst was greater than that of the substrate, which is conducive for the entry of the substrate into the reactor channel. The spin-induced fluid disturbance promoted substrate replenishment around the catalyst, thereby improving the mass-transfer efficiency and increasing the primary kinetic constant to 16.5-fold of that of the stationary hydrogel while maintaining stability. Therefore, the MCR proposed in this study offers a novel approach for improving the catalytic mass-transfer efficiency of precious metals and exhibits potential application value in remediating environmental pollution and catalysis.

Self-Assembly-Assisted Dynamic Placement of Noble Metals Selectively on Multifunctional Carbide Supports for Alkaline Hydrogen Electrocatalysis

Atomically dispersed catalysts are ideal for alkaline hydrogen electrocatalysis with low noble metal loadings. However, previous designs have exhibited insufficient *OH binding and low cell performance, which limit their application...

High stability of electrocatalytic hydrogen evolution from Ru-WC/NC 0D-2D nanocomposites

Pt based noble metal catalysts are important and efficient electrocatalysts during hydrogen evolution reaction (HER). However, the HER of Pt based noble metal catalysts have poor stability and high cost. Herein, Unique Ru loaded the tungsten carbide/nitrogen doped carbon (Ru-WC/NC) 0D-2D nanocomposites were fabricated by gas-phase reduction pyrolysis process to solve the problem of poor stability and high cost. Specifically, 0D WC-supported ultra-small Ru (∼2 nm) was anchored on nitrogen doped carbon nanosheets. Even with a remarkably low Ru loading of just 2.82 %, the developed catalyst achieves comparable high catalytic performance to that of a 20 % Pt/C catalyst and demonstrates superior stability. Under a current density of 10 mA cm−2, the Ru(2)-WC/NC catalyst shows an overpotential of 30 mV in acidic conditions and 51 mV in alkaline environments. Additionally, the overpotential of Ru(2)-WC/NC lower than that of commercially 20 % Pt/C at high current densities exceeding 50 mA cm−2. The total potential of water splitting for the two-electrode system comprising Ru(2)-WC/NC with commercial ruthenium oxide was 1.56 V at 10mA cm−2. Most importantly, the stability of Ru(2)-WC/NC is much better than that of Pt/C. Theoretical calculation results further revealed that the ΔGH* of Ru(2)-WC/NC catalyst could be reduced through synergistic interactions between Ru and WC, thereby optimizing the kinetics of HER. This study offers both theoretical insights and practical methodologies for the synthesis and evaluation of electrocatalysts modified with low loading of noble metals.

Scalable Atomic‐Layer Tailoring of Abundant Oxide Supports Unlocks Superior Interfaces for Low‐Metal‐Loading Dehydrogenation

Liquid organic hydrogen carriers (LOHCs) offer a promising solution for global hydrogen infrastructure, but their practical application faces two key challenges: sluggish dehydrogenation processes and the reliance on catalysts with high noble metal loadings. This study presents a scalable approach to reduce noble metal usage while maintaining high catalytic activity. We synthesized an ultralow Pt content (0.1 wt%) catalyst using γ‐Al2O3‐based pellet support with atomic layer deposition (ALD) of TiO2. Advanced characterization techniques reveal that the thin ALD‐TiO2 shell provides a heterogeneous interface, confining electronically rich Pt‐nanoparticle ensembles. The catalyst outperforms both equivalent Pt‐content catalysts and a commercial 0.5 wt% Pt/γ‐Al2O3 catalyst in homocyclic LOHC dehydrogenation. This study provides insights into the beneficial role of ALD‐engineered interfaces for catalytic supports and offers an efficient approach for scalable production of low‐noble‐metal‐content catalysts, with implications for various catalytic processes.

Scalable Atomic-Layer Tailoring of Abundant Oxide Supports Unlocks Superior Interfaces for Low-Metal-Loading Dehydrogenation.

Liquid organic hydrogen carriers (LOHCs) offer a promising solution for global hydrogen infrastructure, but their practical application faces two key challenges: sluggish dehydrogenation processes and the reliance on catalysts with high noble metal loadings. This study presents a scalable approach to reduce noble metal usage while maintaining high catalytic activity. We synthesized an ultralow Pt content (0.1 wt %) catalyst using γ-Al2O3-based pellet support with atomic layer deposition (ALD) of TiO2. Advanced characterization techniques reveal that the thin ALD-TiO2 shell provides a heterogeneous interface, confining electronically rich Pt-nanoparticle ensembles. The catalyst outperforms both equivalent Pt-content catalysts and a commercial 0.5 wt % Pt/γ-Al2O3 catalyst in homocyclic LOHC dehydrogenation. This study provides insights into the beneficial role of ALD-engineered interfaces for catalytic supports and offers an efficient approach for scalable production of low-noble-metal-content catalysts, with implications for various catalytic processes.

Study on the Effect and Mechanism of Pt and Au noble metal loading on TiO2 Catalysts for CO2 Photo-Thermal Reduction

Study on the Effect and Mechanism of Pt and Au noble metal loading on TiO₂ Catalysts for CO₂ Photo-Thermal Reduction

Active and stable plasma-enhanced ALD Pt@Ni-YSZ hydrogen electrode for steam reversible solid oxide cells

Designing and fabricating active and thermally stable bifunctional catalysts with minimal noble metal loadings are crucial for reversible solid oxide cells (rSOCs). This study employed Pt nanoparticles fabricated via plasma-enhanced atomic layer deposition (PEALD) to a nickel-yttria stabilized zirconia (Ni-YSZ) electrode to serve as effective catalysts in fuel cell and electrolysis modes. Despite the minimal Pt catalyst loading (<1 μg cm–2), the PEALD Pt@Ni-YSZ catalytic electrode exhibited superior electrochemical performance, (20 % higher than the bare cell), both in the fuel cell and electrolysis modes. Remarkably, this performance is sustained without any degradation over a 50 h duration at 700 °C. Dissimilar stabilization behaviors of the Pt catalysts occurred as distributed fine particles on Ni and anchored coarsened particles at the grain boundaries on YSZ surfaces. Furthermore, the mechanism of the enhanced hydrogen evolution/oxidation reactions with the PEALD Pt@Ni-YSZ electrode was verified using density functional theory simulations.

Recent progress on non-metallic carbon nitride for the photosynthesis of H2O2: Mechanism, modification and in-situ applications

Photocatalytic hydrogen peroxide (H2O2) production has been considered as a promising strategy for H2O2 synthesis due to its environmentally friendly. Among various photocatalysts, carbon nitride-based materials are excellent candidates for H2O2 production because of their excellent visible-light response, low cost and high stability. In this review, we summarize in detail the research progress on the photocatalytic production of H2O2 by carbon nitride. First, we summarize the basic principles of photocatalysis and photocatalytic H2O2 production. Second, the classification and modification methods of carbon-nitride-based materials are discussed, including morphology modulation, noble metal loading, defect control, heterojunction regulation, molecular structure engineering and elemental doping. Finally, the different in-situ applications of H2O2via photosynthesis were discussed, including disinfection and antibiotic resistant genes degradation, organic pollutants degradation, medical applications and fine chemical synthesis. This review brings great promise for in-situ H2O2 photosynthesis, which is expected to serve as a key component in future applications.

Constructing CoP/Ni2P Heterostructure Confined Ru Sub-Nanoclusters for Enhanced Water Splitting in Wide pH Conditions.

Developing efficient electrocatalysts for water splitting is of great significance for realizing sustainable energy conversion. In this work, Ru sub-nanoclusters anchored on cobalt-nickel bimetallic phosphides (Ru-CoP/Ni2P) are constructed by an interfacial confinement strategy. Remarkably, Ru-CoP/Ni2P with low noble metal loading (33.1µgcm-2) shows superior activity for hydrogen evolution reaction (HER) in all pH values, whose turnover frequency (TOF) is 8.7, 15.3, and 124.7 times higher than that of Pt/C in acidic, alkaline, and neutral conditions, respectively. Meanwhile, it only requires the overpotential of 171 mV@10mAcm-2 for oxygen evolution reaction (OER) and corresponding TOF is 20.3 times higher than that of RuO2. More importantly, the Ru-CoP/Ni2P||Ru-CoP/Ni2P displays superior mass activity of 4017mAmgnoble metal -1 at 2.0V in flowing alkaline water electrolyzer, which is 105.1 times higher than that of Pt/C||IrO2. In situ Raman spectroscopy demonstrates that the Ru sites in Ru-CoP/Ni2P play a key role for water splitting and follow the adsorption evolution mechanism toward OER. Further mechanism studies disclose the confined Ru atom contributes to the desorption of H2 during HER and the formation of O-O bond during OER, leading to fast reaction kinetics. This study emphasizes the importance of interface confinement for enhancing electrocatalytic activity.

Isolated Pt Atoms Stabilized by Ga2O3 Clusters Confined in ZSM-5 for Nonoxidative Activation of Ethane.

Selective activation of light alkanes is an essential reaction in the petrochemical industry for producing commodity chemicals, such as light olefins and aromatics. Because of the much higher intrinsic activities of noble metals in comparison to non-noble metals, it is desirable to employ solid catalysts with low noble metal loadings to reduce the cost of catalysts. Herein, we report the introduction of a tiny amount of Pt (at levels of hundreds of ppm) as a promoter of the Ga2O3 clusters encapsulated in ZSM-5 zeolite, which leads to ∼20-fold improvement in the activity for ethane dehydrogenation reaction. A combination of experimental and theoretical studies shows that the isolated Pt atoms stabilized by small Ga2O3 clusters are the active sites for activating the inert C-H bonds in ethane. The synergy of atomically dispersed Pt and Ga2O3 clusters confined in the 10MR channels of ZSM-5 can serve as a bifunctional catalyst for the direct ethane-benzene coupling reaction for the production of ethylbenzene, surpassing the performances of the counterpart catalysts made with PtGa nanoclusters and nanoparticles.

ZnO nanowires decorated with Pt nanoclusters for selective detection of ppb-level nitrogen dioxide

Noble metal loading is an efficient way to improve the sensing performance of metal oxide semiconductor (MOS) gas sensors. In this work, platinum (Pt) nanoclusters loaded ZnO nanowires (Ptc-ZnO) were used to fabricate a NO2 sensor. Pure ZnO nanowires were prepared by a solvothermal method and Pt nanoclusters were loaded via a sacrificial templating route. The Ptc-ZnO based sensor with a trace of Pt loading (0.17 wt%) shows a high response to ppb-level NO2 (26.1–100 ppb), 4.4 times higher than that of pure ZnO. Additionally, it also exhibits excellent selectivity, low theoretical limit of detection (1.19 ppb) and good stability to humidity. The enhancing mechanism on gas sensing performance by Pt loading was discussed and investigated via HAADF-STEM, XPS, NO2-TPD and other methods. This work provides a way to develop gas sensor for ultralow NO2 concentration real-time detection.

Formation of low-coordination Pt clusters on Al vacancy-induced CoAl layered double hydroxides-derived oxides enhances low-temperature oxidation performance of HCHO

Noble metal loading and oxygen vacancy construction are prevalent strategies to enhance catalyst performance in HCHO catalytic oxidation. For noble metal systems, most cutting-edge research focuses on single atoms, including the exploration of coexistence between single atoms and clusters, yet there are few reports on the impact of noble metal clusters with different coordinations on catalyst performance. Additionally, investigations into metal vacancies, as opposed to oxygen vacancies, are also scarce. In this work, we used CoAl layered double hydroxides (LDHs) as a precursor, which, after calcination and etching, yielded derived oxides with Al vacancies (LDO5). Pt was then loaded onto the surface of these oxides via impregnation (Pt/LDO5). Activity tests demonstrated that Pt/LDO5 exhibited superior HCHO oxidation activity, especially at low temperatures, compared to Pt/LDO. Utilizing high-resolution transmission electron microscopy (HRTEM) and X-ray absorption fine structure (XAFS), we discovered that, in contrast to the “standard” Pt clusters on the LDO surface, Pt primarily existed as low-coordination clusters on the LDO5 surface, even with a higher Pt loading. Moreover, the coexistence of Al vacancies and low-coordination Pt clusters effectively enhanced the spin state of Co species in the support and altered the direction of electron transfer between Pt and the support.

Solution-plasma treatment for synthesizing Ketjenblack-supported Pt (1 1 1) nanocatalysts with ultra-low overpotential for Li-O2 batteries

Reducing the loading of noble metals to achieve high catalytic activity is key to enhancing the performance and reducing the cost of lithium-oxygen (Li-O2) batteries. In this study, a highly dispersed platinum (111) catalyst supported on Ketjenblack (p-Pt/KBs) is synthesized using a novel approach that involves the interaction between solution and nonthermal plasma (SNP). The influence of different glow discharge voltages on morphology and performance of catalytic materials is investigated. The results show that the electrocatalyst prepared at 400 V has uniform Pt (111) nanocrystals embedded on Ketjenblack, achieved through plasma-induced decomposition of H2PtCl6 followed by nucleation and growth. The designed catalyst, when used as the cathode catalyst in Li-O2 batteries, demonstrates lower polarization losses with an overall overpotential of only 0.24 V compared to commercial platinum on carbon (Pt/C). The plasma effect results in significantly increased defects and grafted oxygen-containing functional groups on the support surface, providing abundant active sites conducive to anchoring of Pt nanoparticles (NPs) onto the scaffold and promoting their electronic coupling. Moreover, dominant mesopores offer ample triple-phase active zones that facilitates lithium-ion transport and rapid oxygen diffusion, further lowering energy barrier for Li2O2 decomposition and reducing the charge overpotential.

Highly Active Oxidation Catalysts through Confining Pd Clusters on CeO2 Nano‐Islands

AbstractCeO2‐supported noble metal clusters are attractive catalytic materials for several applications. However, their atomic dispersion under oxidizing reaction conditions often leads to catalyst deactivation. In this study, the noble metal cluster formation threshold is rationally adjusted by using a mixed CeO2‐Al2O3 support. The preferential location of Pd on CeO2 islands leads to a high local surface noble metal concentration and promotes the in situ formation of small Pd clusters at a rather low noble metal loading (0.5 wt %), which are shown to be the active species for CO conversion at low temperatures. As elucidated by complementary in situ/operando techniques, the spatial separation of CeO2 islands on Al2O3 confines the mobility of Pd, preventing the full redispersion or the formation of larger noble metal particles and maintaining a high CO oxidation activity at low temperatures. In a broader perspective, this approach to more efficiently use the noble metal can be transferred to further systems and reactions in heterogeneous catalysis.

Highly Active Oxidation Catalysts through Confining Pd Clusters on CeO2 Nano-Islands.

CeO2-supported noble metal clusters are attractive catalytic materials for several applications. However, their atomic dispersion under oxidizing reaction conditions often leads to catalyst deactivation. In this study, the noble metal cluster formation threshold is rationally adjusted by using a mixed CeO2-Al2O3 support. The preferential location of Pd on CeO2 islands leads to a high local surface noble metal concentration and promotes the in situ formation of small Pd clusters at a rather low noble metal loading (0.5 wt %), which are shown to be the active species for CO conversion at low temperatures. As elucidated by complementary in situ/operando techniques, the spatial separation of CeO2 islands on Al2O3 confines the mobility of Pd, preventing the full redispersion or the formation of larger noble metal particles and maintaining a high CO oxidation activity at low temperatures. In a broader perspective, this approach to more efficiently use the noble metal can be transferred to further systems and reactions in heterogeneous catalysis.

Induced-aggregates in photocatalysis: An unexplored approach to reduce the noble metal co-catalyst content

Photocatalysis has emerged as a promising and environmentally sustainable solution to produce high-purity hydrogen through ethanol photoreforming. It is commonly accepted that adding co-catalysts, especially noble metals, significantly enhances the catalytic activity of semiconductors. However, the high cost of noble metals such as Pt may limit the real application of this emerging technology. Here we evaluate the possibility of reducing the noble metal loading by creating the appropriate interface between pre-formed semiconductor nanoparticles. Commercial titania (P25) was selected as the semiconductor due to its commercial availability, facilitating the straightforward validation and corroboration of our results. Pt was selected as co-catalyst because one of the most efficient photocatalysts for the ethanol photo-reforming is still based on the use of P25 in combination with Pt. We report that the creation of induced aggregates dramatically improves the total hydrogen produced when very low loadings (≤0.05 wt%) of Pt are used. We have developed a pioneering reactor designed for conducting photoluminescence studies under authentic operational conditions of nanoparticle suspensions in the liquid phase. This approach allows us to obtain the average photoluminescence emission from the P25 agglomerates what it would be impossible to obtain by using standard solid samples holders. Thanks to this equipment, we can conclude that this remarkable improvement of the activity is mainly due to creation of an interface that favors the charge transfer between the particles of the aggregates. According to this, the titania nanoparticles of the agglomerates act as an antenna to collect the photons of the sun-light and produce the photo-excited electrons that will be transferred to the platinum nanoparticles located in the same agglomeration. In contrast, raw P25 with low loadings of Pt would have a high number of titania nanoparticles without platinum, and therefore, inactive. This result would be especially relevant in the case of immobilized photocatalytic systems for real future photocatalytic reactors because the immobilization of the semiconductors would generate similar interactions to the one created by our method. Consequently, the initial semiconductor immobilization followed by the subsequent photo-deposition of the co-catalyst emerges as a promising approach for a substantial reduction of the co-catalyst content.

Distribution Tendencies of Noble Metals on Fe(100) Using Lattice Gas Cluster Expansions.

Fe-based catalysts are highly selective for the hydrodeoxygenation of biomass-derived oxygenates but are prone to oxidative deactivation. Promotion with a noble metal has been shown to improve oxidative resistance. The chemical properties of such bimetallic systems depend critically on the surface geometry and spatial configuration of surface atoms in addition to their coverage (i.e., noble metal loading), so these aspects must be taken into account in order to develop reliable models for such complex systems. This requires sampling a vast configurational space, which is rather impractical using density functional theory (DFT) calculations alone. Moreover, "DFT-based" models are limited to length scales that are often too small for experimental relevance. Here, we circumvent this challenge by constructing DFT-parametrized lattice gas cluster expansions (LG CEs), which can describe these types of systems at significantly larger length scales. Here, we apply this strategy to Fe(100) promoted with four technologically relevant precious metals: Pd, Pt, Rh, and Ru. The resultant LG CEs have remarkable predictive accuracy, with predictive errors below 10 meV/site over a coverage range of 0 to 2 monolayers. The ground state configurations for each noble metal were identified, and the analysis of the cluster energies reveals a significant disparity in their dispersion tendency.

Engineering bimetallic single-atom catalysts utilizing the reducibility of HxMoO3 for high efficiency hydrogen evolution

Bimetallic single-atom catalysts have garnered substantial interest due to their extraordinary catalytic prowess, which arises from atomic-level synergistic effects that can significantly enhance hydrogen evolution reaction (HER) kinetics beyond the capabilities of monometallic single-atom catalysts. However, the fabrication of bimetallic single-atom catalysts remains a tremendous challenge. Herein, we introduce an in-situ reduction method to fabricate bimetallic single-atom catalysts anchored on hydrogenated molybdenum trioxide (HxMoO3, 0 < x ≤ 2). Intriguingly, HxMoO3 exhibits inherent reducing capabilities that facilitate the in-situ reduction of some metal ions to metallic single atoms in steps on its surface, thereby enabling the constructing of bimetallic single-atom structures. As a testament to this strategy, the prepared PtM/HxMoO3 catalysts (M = Ag, Au, Pd, Rh) with ultra-low noble metal loadings (wt% < 1%) on the nano-HxMoO3 support exhibit remarkable efficiency in HER. Outperforming both monometallic single-atom catalysts (M/HxMoO3) and commercial Pt/C, these catalysts demonstrate enhanced HER performance, and the PtPd/HxMoO3 exhibits outstanding performance with an overpotentials of 10 mV at 10 mA/cm2, Tafel slope of 36 mV/dec, and long-term durability in acidic media. The presence of Pt single-atom significantly enhances the electrochemical surface area (ECSA) and accelerates the kinetics of the HER for other metal single atoms.

High-efficient electrooxidation of ethylene glycol and ethanol on PdSn alloy loaded by versatile poly(3,4-ethylenedioxythiophene)

Developing a novel catalyst with lower noble-metal loading and higher catalytic efficiency is significant for promoting the widespread application of direct alcohol fuel cells (DAFCs). In this work, poly(3,4-ethylenedioxythiophene) (PEDOT) supported the PdSn alloy (PdSn/PEDOT) were simply synthesized and their electrocatalytic performance toward the oxidation of ethylene glycol and ethanol (EGOR and EOR) were investigated in alkaline media, respectively. In comparison with other control catalysts, the optimized Pd4Sn6/PEDOT catalyst exhibits the highest mass activity (7125/4166 mA mgPd−1) and specific activity (26/15 mA cm−2) towards EGOR/EOR. The mass activity of Pd4Sn6/PEDOT for EGOR and EOR are 11.9 and 10.9 times higher than commercial Pd/C, respectively. Moreover, chronoamperometry (CA) and successive cyclic voltammetry (CV) tests show that the CO resistance ability and durability of the Pd4Sn6/PEDOT catalyst were superior to Pd4Sn6, Pd/PEDOT and commercial Pd/C catalysts, which can be attributed to the d-band center of Pd can be effectively downshifted and the interface strain effect between electrons caused by the conjugated structure between PEDOT groups. This work provides an effective strategy for the development of highly efficient anode catalysts of DAFCs.

Experimental study of low-temperature combustion performance in hydrogen/air mixtures over Pt–Cu/HZSM-5/cordierite bimetallic catalysts

Catalytic combustion provides a feasible technology to effectively avoid NOx formation due to the high temperature in the process of hydrogen combustion. Recently, the development of efficient and affordable catalysts has attracted extensive attention as the cost of noble metals remained high. In this study, a list of cordierite monolithic catalysts with low noble metal loading are prepared by introducing the appropriate amount of transition metals (Mn, Cu, Fe, Co, and Ce), and their catalytic performance are further investigated. On this basis, the study on catalytic stability and kinetic is carried out, and the synergistic interaction between the bimetals is revealed with comprehensive characterization methods. The results show that Cu could promote the reaction rate of the Pt-based catalyst which show the best catalytic performance with the Cu loading of 1 g/L. The ignition temperature T10 is 58.5 °C, and the burnout temperature T100 is 100 °C, with activation energy as low as 44.00 kJ/mol. The enhancement of the catalytic performance is attributed to the interaction between the bimetallic elements. On the one hand, the valence state of Cu and Pt is changed, and on the other hand the dispersion of Pt get improved, which contributed to the catalytic reaction rate.