Dehydrogenation Activity Research Articles

Phosphorus-modification of Pt/Al2O3 catalysts improves dispersion and cycloalkane dehydrogenation activity

In this study, we demonstrate that phosphorus-modification of Pt/Al2O3 leads to sinter-stable catalysts with improved activity in the dehydrogenation of perhydro benzyltoluene, an attractive liquid organic hydrogen carrier. TEM images show that platinum nanoparticles are stabilized to a size below 1 nm by the P-modification procedure, while unmodified counterparts show considerable sintering after reduction at 600 °C. The modification procedure starts by a simple impregnation of Pt/Al2O3 with H3PO3, followed by a high temperature treatment above 550 °C. It is crucial to adjust the right P:Pt ratio to reach stabilization of all platinum nanoparticles and thereby high catalytic surface areas. In our dehydrogenation studies, a catalyst with the optimal molar P:Pt ratio of 1.8 shows a 18 % higher activity compared to the unmodified sample. Even after treating the catalyst at temperatures up to 900 °C, this activity boost remains. XPS and XRD measurements prove that Pt stays in its reduced elemental state, also after P-modification, which is essential for a good dehydrogenation activity. The phosphorus species act as an anchor for the Pt particles on the Al2O3 surface, reducing their mobility and preserving small nanoparticles.

PH-dependent growth of alumina nanorods with a high aspect ratio for enhanced propane dehydrogenation performance

Controllable synthesis of porous alumina is always challenging due to the diversity of precursors and the complexity of the growth process. In this work, alumina nanorods with adjustable aspect ratios were synthesized by precipitation to investigate the morphology evolution mechanism related to aging pH, and the structure–activity relationship of alumina. The evolution path of precursors ammonium aluminum carbonate hydroxide (NH4Al(OH)2CO3, AACH) was established by tracking the variation in electrical charges and nitrate concentration during the growth process. It was revealed that the anisotropic adsorption of ions on the AACH crystal facets can modulate the axial and radial growth rates of the microcrystalline rods, regulating the one-dimensional oriented assembly of AACH. Alumina synthesized at pH 9.5 exhibited more exposition of (100) facets due to its higher aspect ratio, resulting in an aluminum content of up to 30% in the five-coordinated state. Due to the presence of strong metal-support interactions, the corresponding PtSn/Al2O3 catalyst demonstrated good propane dehydrogenation activity and stability, with propylene formation with 99% selectivity within 30 h of reaction. This study highlighted the significance of pH regulation in the growth environment of AACH, enabling the selective exposure of crystal facets in the alumina support, and providing an effective pathway to obtain highly active and stable catalysts.

Novel nanoporous amorphous/nanocrystalline composite structured RuNiFeCo multicomponent alloys with exceptional catalytic activity for ammonia borane hydrolytic dehydrogenation

The pursuit of high-efficient and cost-effective catalysts for hydrogen generation is imperative to address the energy crisis. Herein, nanoporous RuNiFeCo alloys (np-RuNiFeCo) with high catalytic activity for ammonia borane (AB) hydrolytic dehydrogenation have been prepared by dealloying Fe25NixCo40-xRu5B30 (x = 0–40) high-entropy amorphous alloys with low Ru content. The np-RuNiFeCo are composed of an amorphous/hexagonal close-packed Ru nanocrystalline dual-phase structure and exhibit a uniform nanopore/ligament bicontinuous architecture. The morphology, composition, and AB hydrolysis catalytic properties of the np-RuNiFeCo can be regulated by varying the Ni/Co content in the precursors, and the best catalytic activity with a high turnover frequency value of 148.2 molH2molRu‐1min‐1 and a low apparent activation energy of 25.3 kJmol‐1 was obtained when x = 30. Density functional theory simulations indicate that the presence of Ni, synergizing with Fe and Co, promotes electron transfer to Ru and enhances the adsorption energies of both AB and H2O molecules while reducing the activation barrier for cleaving the H2O molecule, leading to enhanced intrinsic catalytic activity of the alloy. The exceptional catalytic performance of the np-RuNiFeCo arises from the synergy of multiple principal elements, nanoporous morphology, and amorphous/nanocrystalline heterogeneous interface. In addition, the mechanisms of dealloying and nanoporous structure formation have been discussed based on surface diffusion.

Bimetallic PtZn nanoparticles anchored in high-silica SSZ-13 zeolite for efficient propane dehydrogenation

Direct dehydrogenation of propane to propylene (PDH) is a promising route to meet the ever-growing global propylene demand, but the industrial Pt-based catalysts usually suffer from serious deactivation derived from coke deposition and sintering under harsh reaction conditions. In this work, PtZn bimetallic nanoparticles encapsulated into high-silica SSZ-13 zeolites (PtZn@SSZ-13) were synthesized via a facile ligand-protected interzeolite transformation strategy. In a PDH reaction, the synthesized 0.5Pt3Zn@SSZ-13 catalyst exhibits superior catalytic performance with a propane conversion of 23.7% and a propylene selectivity of 96.8%, which is significantly better than that of PtZn supported on high-silica SSZ-13 (0.5Pt3Zn/SSZ-13). Particularly, the high catalytic activity of this catalyst can be kept during three successive oxidation–reduction cycles. Detailed characterizations including HAADF-STEM, XPS, UV–Vis, H2-TPR reveal that the remarkable improvement of PDH performance is attributed to the PtZn synergistic effect as well as the confinement of SSZ-13 zeolites. The DFT calculations and microkinetic simulations also evidenced that the Pt particles anchored on the Zn-doped SSZ-13 zeolite pore framework possessed obviously higher propane dehydrogenation activity, whereas the anti-coking ability of 0.5Pt3Zn@SSZ-13 was also stronger than Pt (111) surface, demonstrating the superior performance of 0.5Pt3Zn@SSZ-13.

Enhanced propane dehydrogenation performance using bimetallic-modified GaPt/SiO2-Al2O3 with ultralow-loading Pt

Propane dehydrogenation (PDH) is used to increase propylene production and to produce hydrogen as a by-product. Despite the widespread utilisation of Pt-loaded catalysts in industrial PDH operations, challenges such as excessive noble metal loading and coking persist in the face of rigorous reaction conditions. These hindrances limit to achieving the optimal economic efficiency. In this work, we report a method aimed at reducing Pt loading to only 0.05 wt% through synergistic modification of GaPt catalysts loaded on SiO2-Al2O3 supports (i.e. SIRAL) with K and Ce. The resulting catalysts exhibit remarkable stability and elevated activity for propane dehydrogenation. The K+ and SiO2 could modulate the support surface acidity and immobilizes the active tetrahedral Ga3+ sites, which improves the catalytic performance and reduce coke deposition. Furthermore, the inclusion of Ce decreases the electron density of the Pt species, stabilizing the atomically dispersed Pt and enhances the formation of active Pt sites, which effectively impedes the Pt agglomeration. As a result, the GaPtKCe/SIRAL10 catalyst demonstrates excellent catalytic performance, achieving 47% propane conversion and >96% propylene selectivity, while maintaining notable stability with 0.016 h−1 deactivation rate constant at 580 °C, even without hydrogen co-feed.

Structural Evolution of GaOx-Shell and Intermetallic Phases in Ga-Pt Supported Catalytically Active Liquid Metal Solutions.

We present a comprehensive scale-bridging characterization approach for supported catalytically active liquid metal solutions (SCALMS) which combines lab-based X-ray microscopy, nano X-ray computed tomography (nano-CT), and correlative analytical transmission electron microscopy. SCALMS catalysts consist of low-melting alloy particles and have demonstrated high catalytic activity, selectivity, and long-term stability in propane dehydrogenation (PDH). We established an identical-location nano-CT workflow which allows us to reveal site-specific changes of Ga-Pt SCALMS before and after PDH. These observations are complemented by analytical transmission electron microscopy investigations providing information on the structure, chemical composition, and phase distribution of individual SCALMS particles. Key findings of this combined microscopic approach include (i) structural evolution of the SCALMS particles' GaOx shell, (ii) Pt segregation toward the oxide shell leading to the formation of Ga-Pt intermetallic phases, and (iii) cracking of the oxide shell accompanied by the release of liquid Ga-Pt toward the porous support.

One-dimensional Ga2O3-Al2O3 nanofibers with unsaturated coordination Ga: Catalytic dehydrogenation of propane under CO2 atmosphere with excellent stability

The pressing demand for propylene has spurred intensive research on the catalytic dehydrogenation of propane to produce propylene. Gallium-based catalysts are regarded as highly promising due to their exceptional dehydrogenation activity in the presence of CO2. However, the inherent coking issue associated with high temperature reactions poses a constraint on the stability development of this process. In this study, we employed the electrospinning method to prepare a range of Ga2O3-Al2O3 mixed oxide one-dimensional nanofiber catalysts with varying molar ratios for CO2 oxidative dehydrogenation of propane (CO2-OPDH). The propane conversion was up to 48.4 % and the propylene selectivity was high as 96.8 % at 500 °C, the ratio of propane to carbon dioxide is 1:2. After 100 h of reaction, the catalyst still maintains approximately 10 % conversion and exhibits a propylene selectivity of around 98 %. The electrospinning method produces one-dimensional nanostructures with a larger specific surface area, unique multi-stage pore structure and low-coordinated Ga3+, which enhances mass transfer and accelerates reaction intermediates. This results in less coking and improved catalyst stability. The high activity of the catalyst is attributed to an abundance of low-coordinated Ga3+ ions associated with weak/medium-strong Lewis acid centers. In situ infrared analysis reveals that the reaction mechanism involves a two-step dehydrogenation via propane isocleavage, with the second dehydrogenation of Ga-OR at the metal–oxygen bond being the decisive speed step.

From waste to raw chemicals: Catalytic transformation of fusel oil by mixed metal oxides

In this study, we detail a catalytic process for the conversion of fusel oil (FO), a by-product of ethanol production considered as waste, into valuable organic compounds, including aldehydes, alkenes, ketones, and alkylbenzenes spanning a carbon chain length from C6 to C12. The reaction was carried out in a fixed bed flow reactor at atmospheric pressure, employing mixed metal oxides (MMO) derived from hydrotalcites (HTC) as catalysts. The HTC were readily synthesized by co-precipitation method involving Mg2+ and Al3+, wherein 20 mol% Mg2+ was substituted by M2+ = Mn, Fe, Co, Ni, Cu, and Zn, and MMO obtained by HTC calcination. These catalysts offer cost-effectiveness compared to noble metal-containing ones while exhibiting remarkable activity in dehydrogenation, hydrogenation, and dehydration reactions pivotal for alcohol reactivity. The proposed methodology holds promise for large-scale industrial use and pioneers a fresh avenue for deriving value-added raw chemicals from a renewable carbon source.

Synergistic structural and electronic influences of Pt bead catalysts on dehydrogenation activity for liquid organic hydrogen carriers

Alumina-supported Pt bead catalysts with uniform (PtU/θ-Al2O3) or egg-shell (PtE/θ-Al2O3) structure and their corresponding potassium-doped counterparts (K-PtU/θ-Al2O3, K-PtE/θ-Al2O3) were synthesized to elucidate the influence of structure-induced active metal distribution and promotor on the dehydrogenation of liquid organic hydrogen carriers (LOHCs). Characterizations of the catalysts confirmed that different synthetic methods led to distinct Pt distributions on the Al2O3 surface. PtE/θ-Al2O3 and K-PtE/θ-Al2O3 had an average size of 1 nm with narrow Pt distributions while PtU/θ-Al2O3 and K-PtU/θ-Al2O3 exhibited bimodal distributions in Pt particle size (<0.2 nm and <0.8 nm), which also influenced the oxidation states. Introducing the promotor (K) facilitated electron transfer into Pt, which resulted in a more metallic state. When applied to the dehydrogenation of two different LOHCs, including methylcyclohexane and perhydro-monobenzyltoluene, K-PtE/θ-Al2O3 exhibited superior catalytic activity and durability compared to other catalysts. The improved activity of K-PtE/θ-Al2O3 was primarily attributed to the combined electronic influences of the catalyst bulk structure and promotor.

Fine-tuning the electronic properties of Au toward two-dimensional clusters with higher activity for ethanol conversion

Efficient Au/m-ZrO2 catalysts for the conversion of ethanol to acetaldehyde and ethyl acetate were obtained by the deposition precipitation method. The present work investigates the impact of the electronic properties of Au supports on m-ZrO2 catalysts on ethanol dehydrogenation. The Au4f7/2 binding energy (BE) and the average Au-Au nearest-neighbor distances (RAu-Au) were associated with surface defects characterized by CO adsorption. The BE and RAu-Au properties are correlated among themselves, changing by Au loading and pretreatments in an inert atmosphere at different temperatures. Although the RAu-Au unveils a boost of the reaction rates for shorter distances, the coupling of Au and m-ZrO2 produced a bifunctional catalyst. Theoretical studies indicate that molecular ethanol adsorption and formation of the ethoxy intermediate represented a feasible pathway for the activation of ethanol on the Au-ZrO2 interface. The RAu-Au toward of 2D clusters conferred high catalytic activity and low apparent activation energy for ethanol dehydrogenation.

Boosting the catalytic activity of Pd-nanocatalysts by anchoring transition metal atoms on carbon supports for formic acid dehydrogenation

Liquid formic acid (FA) dehydrogenation, which needs high-performance catalysts to generate green hydrogen at room temperature, is a promising chemical hydrogen storage technology that can replace fossil fuels in energy-related devices. In this work, a novel nanocatalyst with ultrafine palladium nanoparticles (Pd NPs) immobilized on a transition metal atom-decorated carbon support was synthesized for the dehydrogenation of liquid FA. Via a hydrothermal of glucose and carbonitride with a following Co doping through a heat treatment process, porous carbons with evenly dispersed Co-sites on it were strategically achieved, which could be used as a support for immobilizing Pd NPs. The obtained Pd/NC-Co1% catalyst exhibited much superior catalytic activities to those samples without Co doping on the support (Pd/NC and PdCo1%/NC), showing an impressive turnover frequency of 3045 h−1 at 50 °C for FA dehydrogenation. Other transition metal species such as Fe- and Ni-decorated carbon nanocatalysts also showed an improved catalytic activity for FA dehydrogenation. This work not only provides an efficient method to synthesize nanocatalysts with ultrafine metal NPs but also demonstrates that highly dispersed metal atoms on the support can effectively affect the immobilized NPs, resulting in an enhancement of catalytic performance.

The Effect of Water Co-Feeding on the Catalytic Performance of Zn/HZSM-5 in Ethylene Aromatization Reactions.

During the methanol-to-aromatics (MTA) process, a large amount of water is generated, while the influence and mechanism of water on the activity and selectivity of the light olefin aromatization reaction are still unclear. Therefore, a study was conducted to systematically investigate the effects of water on the reactivity and the product distribution in ethylene aromatization using infrared spectroscopy (IR), intelligent gravitation analyzer (IGA), and X-ray absorption fine structure (XAFS) characterizations. The results demonstrated that the presence of water reduced ethylene conversion and aromatic selectivity while increasing hydrogen selectivity at the same contact time. This indicated that water had an effect on the reaction pathway by promoting the dehydrogenation reaction and suppressing the hydrogen transfer reaction. A detailed analysis using linear combination fitting (LCF) of Zn K-edge X-ray absorption near-edge spectroscopy (XANES) on Zn/HZSM-5 catalysts showed significant variations in the state of existence and the distribution of Zn species on the deactivated catalysts, depending on different reaction atmospheres and water contents. The presence of water strongly hindered the conversion of ZnOH+ species, which served as the active centers for the dehydrogenation reaction, to ZnO on the catalyst. As a result, the dehydrogenation activity remained high in the presence of water. This study using IR and IGA techniques revealed that water on the Zn/HZSM-5 catalyst inhibited the adsorption of ethylene on the zeolite, resulting in a noticeable decrease in ethylene conversion and a decrease in aromatic selectivity. These findings contribute to a deeper understanding of the aromatization reaction process and provide data support for the design of efficient aromatization catalysts.

Cobalt catalyzed ethane dehydrogenation to ethylene with CO2: Relationships between cobalt species and reaction pathways

TiO2, ZrO2 and a series of TiO2-ZrO2 (TxZ1, x means the atomic ratio of Ti/Zr = 10, 5, 1, 0.2 and 0.1) composite oxide supports were prepared through co-precipitation, and then 3 wt% Co was loaded through wetness impregnation methods. The obtained 3 wt% Co/TiO2 (3CT), 3 wt% Co/ZrO2 (3CZ) and 3 wt% Co/TxZ1 (3CTxZ1) catalysts were evaluated for the oxidative ethane dehydrogenation reaction with CO2 (CO2-ODHE) as a soft oxidant. 3CT1Z1 catalyst exhibits excellent catalytic properties, with C2H4 yield, C2H6 conversion and CO2 conversion about 24.5 %, 33.8 % and 18.0 % at 650 °C, respectively. X-Ray Diffraction (XRD), in-situ Raman, UV–vis diffuse reflectance spectra (UV–vis DRS), H2 temperature-programmed reduction (H2-TPR), Electron paramagnetic resonance (EPR) and quasi in-situ X-ray Photoelectron Spectroscopy (XPS) have been utilized to thoroughly characterize the investigated catalysts. The results revealed that 3CT1Z1 produced TiZrO4 solid solution with more metal defect sites and oxygen vacancies (Ov), promoting the formation of Co2+-TiZrO4 structure. Furthermore, the presence of Ov and Ti3+can facilitate the high dispersion and stabilization of Co2+, as well as suppressing the severe reduction of Co2+, leading to superior ethane oxidative dehydrogenation activity. Besides, less Co0 is beneficial to ODHE reaction, because of its promotion effects for reverse water gas shift reaction; however, more Co0 results in dry reforming reaction (DRE). This work will shed new lights for the design and preparation of highly efficient catalysts for ethylene production.

Catalytic insights into perhydro-benzyltoluene dehydrogenation: Probing surface characteristics revealed by DRIFTS study

The enhancement of dehydrogenation activity in liquid organic hydrogen carriers (LOHC), such as perhydro-benzyltoluene (H12-BT), has been attributed to the addition of various promoters and support modifications into platinum (Pt)-based heterogeneous catalysts. Comprehensive understanding of surface sites predominantly catalyzing the dehydrogenation process is crucial for further enhancing catalytic performance. In this contribution, an in-depth quantitative CO diffuse reflectance infrared Fourier transform spectroscopy (CO-DRIFTS) study on Pt-based catalysts with varying contents of sulfur, known to be effective in dehydrogenation reactions, is performed to unveil the active sites involved in the H12-BT dehydrogenation. Furthermore, while challenges associated with the adsorption step of reactants and products potentially deteriorate catalytic activity, these processes remain open questions for H12-BT dehydrogenation. To shed light on these aspects, we conducted in situ DRIFTS experiments utilizing H12-BT and H0-BT, its dehydrogenated counterpart, to determine the adsorption strength between these molecules and the different catalyst surfaces, influenced by the electron-deficiency effect due to the addition of sulfur. Additionally, our study investigates the correlation between sulfur-induced catalyst surface characteristics and the formation of methane through the demethylation process.

Efficient net transfer-dehydrogenation of glycerol: NNN pincer-Mn and manganese chloride as a catalyst unlocks the effortless production of lactic acid and isopropanol.

Herein, a series of pincer-Mn complexes based on bis(imino)pyridine ligands of the type R2NNN (R = tBu, iPr, Cy and Ph) were synthesized and characterized using various spectroscopic techniques. SCXRD studies revealed a trigonal bipyramidal geometry around the metal center in all the complexes. EPR spectroscopy confirmed the presence of high-spin Mn(II) centers with the consistent observation of sextets in EPR spectra. Additionally, solution magnetic moment measurement exhibited values ranging from 5.8 to 6.2 BM for all the complexes, which are in accordance with the theoretical value of 5.92 BM. HRMS analysis complemented structural characterization, showing fragments corresponding to various solvent adducts and derivatives of the complexes. Subsequently, the synthesized complexes were investigated for their catalytic activity in the transfer dehydrogenation of glycerol to lactic acid in the presence of acetone. Among the considered complexes, the catalyst Ph2NNNMnCl2 was found to be highly efficient. Remarkably, a yield of 92% LA was observed with >99% selectivity at 0.5 mol% loading of Ph2NNNMnCl2 in the presence of 1 equivalent of NaOH at 140 °C in 24 h, surpassing the yield obtained from its precursor MnCl2·4H2O, where a yield of 72% LA was observed with 96% selectivity under similar reaction conditions. This catalytic system was further investigated with a range of acceptors, and good to moderate yields were observed in most cases. Moreover, several control experiments, including reaction with PPh3, CS2 and Hg, highlighted the major involvement of molecular species in the reaction medium. Deuterium labelling studies indicated the involvement of C-H bond activation in the catalytic cycle but not in the rate-determining step (RDS), with a secondary kinetic isotope effect (KIE) of 1.25.

Iridium complexes supported on cross-linked polyacrylic acid as release-and-catch catalysts for continuous formic acid dehydrogenation

We developed an iridium complex on cross-linked polyacrylic acid as a release-and-catch catalyst. It shows FA dehydrogenation activity comparable to homogeneous catalysts, and was recycled 10 times completely, advancing FA-based H2 carriers.

Double-plasmonic-coupled heterojunction photocatalysts for highly-efficient full-spectrum-light-driven H2 evolution from ammonia borane

Methods to enhance the full-spectrum-light-driven water splitting for H2 evolution remain one of the critically important issues to explore advanced photocatalysts. In this study, we present a novel double-plasmon-coupled semiconductor heterojunction photocatalyst with a large number of oxygen vacancies, produced via a simple two-step solvothermal process. These materials represent a new model system to study the kinetics process and catalytic activity of ammonia borane hydrolytic dehydrogenation in a full-spectrum-light-driven plasmonic semiconductor heterostructure. Upon irradiation with full-spectrum light, the resultant photocatalysts are capable of delivering H2 generation rate up to 13,031 μmol g-1h−1, which is ∼6 times greater than that of pristine MoO3-x counterpart. The excellent photocatalytic behavior is primarily attributed to the improved carrier separation, increased light absorption, and enhanced generation of “hot electrons”, enabled by a synergistic photo- and thermo-catalytic effect. Consequently, the high performance of the novel photocatalyst derives from the design of a double-plasmonic-coupling effect and the photocatalyst containing Type-Ⅱ heterojunctions.

A new strategy to fight tumor heterogeneity: Integrating metal-defect active centers within NADH oxidase nanozymes

Constructing robust enzyme mimics capable of disrupting cellular nicotinamide adenine dinucleotide (NAD) homeostasis, such as NADH oxidase (NOX) nanozymes, is emerging as a novel and powerful means to treat cancer. However, owing to the tumor heterogeneity, NOX nanozymes exhibit the different sensitivities toward hypoxic and normoxic cancer cells inside solid tumors, which pose a severe barrier for achieving high therapeutic efficacy. Herein, we propose an innovative design strategy of NOX nanozymes to simultaneously improve the two half-reactions related to NADH oxidation via metal-defect engineering. Taking advantages of distinctive electronic configuration and deprotonation effect around Cu-defect active sites, Cu2−xSe nanozymes perform excellent NADH dehydrogenation activity and preferential 4e- oxygen reduction selectivity, thus decreasing the requirement of O2 in heterogeneous tumor microenvironment. Such unique NADH consumption action of Cu2−xSe nanozymes efficiently disrupts metabolic networks of solid tumor and enables enhanced antitumor efficacy, which provides a new insight on the constructing metal-defect active centers in NOX nanozymes.

Cu, N codoped carbon nanosheets encapsulating ultrasmall Cu nanoparticles for enhancing selective 1,2-propanediol oxidation

In the selective oxidation of biomass-based 1,2-propanediol (PDO) with oxygen as the terminal oxidant, it is challenging to improve the lactic acid (LA) selectivity for nonnoble metal nanoparticles (NPs) due to their limited oxygen reduction rate and easy C–C cleavage. Given the high economic feasibility of nonnoble metals, i.e., Cu, in this work, copper and nitrogen codoped porous carbon nanosheets encapsulating ultrafine Cu nanoparticles (Cu@Cu-N-C) were developed to realize highly selective of PDO oxidation to LA. The carbon-encapsulated ultrasmall Cu0NPs in Cu@Cu-N-C have high PDO dehydrogenation activity while N-coordinated Cu (Cu-N) sites are responsible for the high oxygen reduction efficacy. Therefore, the performance of catalytic PDO conversion to LA is optimized bya proposed pathway of PDO → hydroxylacetone → lactaldehyde → LA. Specifically, the enhanced LA selectivity is 88.5%, and the PDO conversion isup to 75.1% in an O2-pressurized reaction system (1.0 MPa O2), superior to other Cu-based catalysts, while in a milder nonpressurized system (O2flow rate of 100 mL min−1), a remarkable LA selectivity (94.2%) is obtained with 39.8% PDO conversion, 2.2 times higher than that of supported Au nanoparticles (1% Au/C). Moreover, carbon encapsulation offers Cu@Cu-N-C with strong leaching resistance for better recycling.

Rh0.7Ru0.3-MoOx supported on carbon nanotubes boosts hydrogen generation from hydrazine borane at room temperature

Hydrazine borane (HB, N2H4BH3) is gaining attention as a promising chemical hydrogen storage material due to its impressive hydrogen capacity (15.4 wt%) and stability under normal conditions. However, its dehydrogenation properties have remained unsatisfactory despite numerous efforts. In this study, we have successfully developed rhodium-ruthenium nanoparticles modified with MoOx and supported on carbon nanotubes (Rh0.7Ru0.3-MoOx/CNTS) using a facile co-reduction method. Surprisingly, the Rh0.7Ru0.3-MoOx/CNTS catalyst exhibits outstanding performance, surpassing all previously reported activities for HB dehydrogenation. It demonstrates a high turnover frequency (TOF) value of 4412 h−1 at 303 K, 100 % selective conversion of hydrogen, and excellent stability. Through XPS, TEM, BET, and XRD analysis, we have determined that the exceptional performance of Rh0.7Ru0.3-MoOx/CNTS can be attributed to the synergistic effect of CNTS and MoOx on the catalyst's electronic structure, crystal structure, and particle size. These results provide a solid foundation for the potential application of HB in hydrogen fuel cells.