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Substituting slow oxygen evolution reaction (OER) with thermodynamically favorable urea oxidation reaction (UOR) is considered as one of the feasible strategies for achieving energy-saving hydrogen production. Herein, a uniform layer of NiMoO4 nanorods was grown on nickel foam by a hydrothermal method. Then, a series of Ni-MoOx/NF-X nanorod catalysts comprising Ni/NiO and MoOx (MoO2/MoO3) were prepared through regulating annealing atmosphere and reduction temperature. The optimized Ni-MoOx/NF-3 with a large accessible specific area can act as a bifunctional catalyst for electrocatalytic anodic UOR and cathodic hydrogen evolution reaction (HER). At a current density of 100 mA cm−2, the introduction of urea can significantly reduce the overpotential of Ni-MoOx/NF-3 by 210 mV compared to OER. In addition, Ni-MoOx/NF-3 has a higher intrinsic activity than other catalysts. It only requires −0.21 and 1.38 V to reach 100 mA cm−2 in HER and UOR, respectively. Such an excellent performance can be attributed to the synergistic function between Ni and MoOx. The presence of metallic Ni and reduced MoOx in pairs is beneficial for improving the electrical conductivity and modulating the electronic structure, resulting in enhancing the electrocatalytic performance. When assembling Ni-MoOx/NF-3 into an overall urea–water splitting system, it can achieve energy-saving hydrogen production and effective removal of urea-rich wastewater. [ABSTRACT FROM AUTHOR]

The growing demand for sustainable energy solutions highlights the need for advancements in electrocatalysts for direct methanol fuel cells (DMFCs). This study introduces a novel approach to enhance the efficiency and durability of nickel sulfide (NiS) catalysts. We developed a hierarchically porous structure integrated with reduced graphene oxide (rGO) on a nickel foam substrate. Using a dynamic hydrogen bubble template (DHBT) technique, we created a porous nickel scaffold. We then electrodeposited graphene oxide and NiS onto this scaffold, resulting in a hybrid structure termed NiS-rGO-Ni/NF. Characterization through SEM, XRD, and XPS confirmed that the catalyst has a highly porous structure with uniformly distributed Ni 3 S 2 and Ni 3 S 4 phases. The NiS-rGO-Ni/NF catalyst showed significant improvements over conventional NiS/NF. It achieved a peak current density of 84.10 mA/cm2 in the presence of 0.1 M methanol, compared to 30.32 mA/cm2 with NiS/NF. This enhancement is due to the porous nickel layer created using DHBT and the integration of rGO. Additionally, the NiS-rGO-Ni/NF catalyst demonstrated superior reaction kinetics, evidenced by a decrease in the Tafel slope from 204 mV/dec to 122 mV/dec. It also exhibited a remarkable increase in the electrochemically active surface area, reaching 179 cm2 compared to 22 cm2 for NiS/NF. These improvements in surface area and kinetics contribute to its excellent stability, with the catalyst maintaining consistent performance over 20 h of continuous operation. These results underscore the effectiveness of the NiS-rGO-Ni/NF catalyst in methanol oxidation and its potential for more efficient and stable electrochemical applications. • A novel NiS-rGO-Ni/NF electrode for efficient methanol oxidation reaction. • Porous structures and rGO integration enhance electron transfer and surface area. • DFT study reveals efficient non-CO pathways on Ni 3 S 2 and Ni 3 S 4 surfaces. • Electrode keeps 92% of activity after 1000 CV cycles, showing high stability. • Reduced charge transfer resistance confirms superior performance of NiS-rGO-Ni/NF. [ABSTRACT FROM AUTHOR]

The sol-gel method produces supported nickel catalysts possessing good stability. However, the catalysts are plagued by the issue of severe nickel embedment, which limits the accessibility and utilization efficiency of active sites. To address this issue, hard template (e.g., CNTs and SBA-15) was added during the sol-gel synthesis of Ni/CeO 2 , and subsequently removed to optimize the accessibility and stability of Ni nanoparticles on ceria. This approach effectively adjusts the embedment, exposure, deficiency and dispersion of Ni nanoparticles on ceria, thus endows Ni/CeO 2 with high activity, high H 2 selectivity and good stability. As regulated by SBA-15, the Ni/CeO 2 catalyst possesses high specific surface area (128.9 m2/g), abundant oxygen defects, large surface nickel content (5.39%), and small nickel particle size (4.58 nm). The optimized Ni/CeO 2 catalyst achieved a methane conversion of 82% at 650 °C, under a methane GHSV of 10000 mL h−1·g cat −1 and a water/methane ratio of 2. Moreover, this activity is well maintained for 100 h without any deactivation. [Display omitted] • A facile sol-gel method utilizing hard template is developed to synthesize Ni/CeO 2. • Well-balanced exposure and embedment of Ni nanoparticles on CeO 2 is achieved. • Oxygen vacancies and metal-support interaction of Ni/CeO 2 are properly modulated. • Methane conversion and hydrogen selectivity are >80% for 100 h in SMR reaction. [ABSTRACT FROM AUTHOR]

[Display omitted] Expanding the application field of polyolefin materials through functionalization has been a research hotspot in the past three decades. Here, a TiO 2 -supported anilinenaphthoquinone nickel catalyst was assembled and applied for in situ ethylene polymerization with high activity (>2000 kg mol–1h−1) to produce ultra-high molecular weight polyethylene (UHMWPE)/TiO 2 composites with unique physicochemical performance. The UHMWPE/TiO 2 composite films and fibers prepared by in-situ ethylene polymerization are superior to the samples from the blend system in issues such as TiO 2 dispersibility, mechanical property, and photocatalytic degradability. The mechanical properties (strength up to 26.8 cN/dtex, modulus up to 1248.8 cN/dtex) of the obtained UHMWPE/TiO 2 composite fibers are significantly improved with a very low dosage of TiO 2 (as low as 1.4 wt‰). Moreover, UHMWPE/TiO 2 composites obtained by coating Al 2 O 3 and SiO 2 on the surface of TiO 2 not only retain the strong absorption of ultraviolet rays, but also effectively weaken the photocatalytic degradation effect. [ABSTRACT FROM AUTHOR]

Enhancing the kinetics of the oxygen evolution reaction (OER) is imperative for the advancement of water splitting technology. A promising and pressing approach involves the exploration of effective and durable electrocatalysts derived from 3d transition metals. Herein, we present the fabrication of trimetallic FeNiVO x composite catalysts on nickel foam using aerosol-assisted chemical vapor deposition approach for investigating the OER in 1 M KOH solution. The catalysts were deposited for 1, 2, and 3 h to optimize important parameters such as mass loading, morphology, and active sites, with the aim of achieving superior OER activity. The catalyst deposited for 3 h needed minimum overpotentials of 370 mV to attain high oxidation current density of 1 A cm⁻2. This outstanding catalytic performance can be attributed to the effective modulation of the electronic structure among Fe, Ni, and V centers, thereby enhancing the intrinsic active sites. The strong connection between the spherical features and the highly conductive nickel foam contributes to the excellent stability of FeNiVO x , enabling it to maintain its OER performance for up to 40 h. Furthermore, the designed catalysts may serve as promising alternatives to noble metal catalysts for the construction of affordable and clean energy water splitting devices. [Display omitted] • Facile growth of trimetallic FeNiVO x coatings on nickel foam via aerosol-assisted CVD. • Varying deposition time from 1 to 3 h produced spherical morphology in catalysts. • Detailed electrochemical oxygen evolution measurements in alkaline environment. • Optimized FeNiVO x catalyst generated 1 A cm⁻2 at an overpotential of 370 mV. • Catalyst exhibited 40-h stability without changing its structural attributes. [ABSTRACT FROM AUTHOR]

Hydrogen, as an emerging clean energy source, confronts various technical challenges in storage and transportation, notably high costs and operational complexity. With a hydrogen content of up to 17.6 wt%, ammonia is recognized as an exceptionally promising hydrogen storage medium. Its decomposition produces only nitrogen and hydrogen, and its ease of liquefaction at room temperature greatly enhances the ease of storage and transportation. To achieve large-scale ammonia decomposition for hydrogen production, there is an urgent requirement to develop catalysts that are highly active and stable. Although ruthenium-based catalysts currently demonstrate the greatest catalytic activity, their high cost and limited availability impede their widespread commercial application. To tackle this issue, researchers have been dedicated to developing non-precious metal catalysts and synthetic metallic catalysts that are based on more sustainable practices. Nickel and cobalt-based catalysts, in particular, have garnered significant interest due to their relatively lower costs. The current research is focused on enhancing the performance of non-precious metal catalysts by refining their preparation methods and optimizing reaction conditions. In this paper, we outline the fundamental principles of catalytic ammonia decomposition and provide a comprehensive review of the latest advancements in various types of catalysts, with a detailed summary of the findings related to non-precious metal catalysts. It analyzes the performance strengths and limitations of various types of catalysts and offers insights into future research directions. [Display omitted] • The mechanisms of ammonia decomposition are discussed in detail. • Recent progress of ruthenium based catalysts is introduced. • Recent progress in the regulation of non precious metal catalysts is highlighted. • Application prospects of bimetallic catalysts are introduced. • Challenges and future prospects for ammonia decomposition catalysts are outlined. [ABSTRACT FROM AUTHOR]

Supercritical water gasification (SCWG) is a novel energy utilization technology for converting coal into hydrogen (H 2)-rich gas products. Constructing a synergistic catalytic system is crucial for the enhanced production of H 2 in the SCWG of coal. This work constructed a novel synergistic catalytic system, Mo, Co, and Cu were employed to modify titanium dioxide-supported nickel (Ni/TiO 2) catalysts which were added to separate reaction zones independent with potassium carbonate (K 2 CO 3) to exhibit synergistic effects, thereby enhancing H 2 yield. The modification of Ni/TiO 2 can improve the stability of the catalyst by causing lattice shrinkage of TiO 2 , and the synergistic catalytic system exerted much higher carbon gasification efficiency (CGE) and H 2 yield than the non-catalytic condition in this way. Among all the Ni/TiO 2 catalysts, synergistic Ni–Cu/TiO 2 with K 2 CO 3 , which has the smallest Ni particle size, maximized the CGE and H 2 yield from 30.82% to 15.48 mol kg−1 to 95.43% and 81.42 mol kg−1, respectively. The synergistic catalytic mechanism was further revealed, providing theoretical support for the regulation of hydrogen production from SCWG of coal. [Display omitted] • A novel synergistic catalytic system for supercritical water gasification was created. • Transition metals modified Ni/TiO 2 catalysts were synthesized. • NiCu alloy boosts the hydrothermal stability of Ni–Cu/TiO 2 in supercritical water. • Ni–Cu/TiO 2 synergized with K 2 CO 3 achieved an H 2 yield of 81.42 mol kg−1. • A comprehensive synergistic catalytic mechanism was revealed. [ABSTRACT FROM AUTHOR]

The Li-O2 battery (LOB) has attracted growing interest, including for its great potential in next-generation energy storage systems due to its extremely high theoretical specific capacity. However, a series of challenges have seriously hindered LOB development, such as sluggish kinetics during the oxygen reduction and oxygen evolution reactions (ORR/OER) at the cathode, the formation of lithium dendrites, and undesirable corrosion at the lithium metal anode. Herein, we propose a strategy based on the ultra-low loading of atomic Ni catalysts to simultaneously boost the ORR/OER at the cathode while stabilizing the Li metal anode. The resultant LOB delivers a superior discharge capacity (> 16,000 mAh g-1), excellent long-term cycling stability (> 200 cycles), and enhanced high rate capability (> 300 cycles @ 500 mA g-1). The working mechanisms of these atomic Ni catalysts are revealed through carefully designed in situ experiments and theoretical calculations. This work provides a novel research paradigm for designing high-performance LOBs that are useable in practical applications. [ABSTRACT FROM AUTHOR]

Some novel manganese and nickel complexes were synthesized by reacting manganese(II) dichloride and nickel(II) dichloride with pyridyl-imine ligands differing in the nature of the substituents at the imino nitrogen atom. All the complexes were characterized by analytical and infrared data: for some of them single crystals were obtained, and their molecular structure was determined by X-ray diffraction. The complexes were used in association with methylaluminoxane (MAO) for the polymerization of 1,3-butadiene obtaining active and selective catalysts giving predominantly 1,2 polybutadiene in case of manganese catalysts and exclusively cis-1,4 polybutadiene in case of nickel catalysts. [ABSTRACT FROM AUTHOR]

Geometrically defined allylic alcohols with SE, SZ, RE and RZ stereoisomers serve as valuable intermediates in synthetic chemistry, attributed to the stereoselective transformations enabled by the alkenyl and hydroxyl functionalities. When an ideal scenario presents itself with four distinct stereoisomers as potential products, the simultaneous control vicinal stereochemistry in a single step would offer a direct pathway to any desired stereoisomer. Here, we unveil a metallaphotoredox migration strategy to access stereodefined allylic alcohols through vinylic C−H activation with aldehydes. This method harnesses a chiral nickel catalyst in concert with a photocatalyst to enable a 1,4‐Ni migration by using readily accessible 2‐vinyl iodoarenes as starting materials. The efficacy of this methodology is highlighted by the precise construction of all stereoisomers of allylic alcohols bearing analogous substituents and the efficient synthesis of key intermediates en route to Myristinin family. Experimental and computational studies have shed light on pivotal aspects including the synergy of metal catalysis and photocatalysis, the driving forces behind the migration, and the determination of absolute configuration in the C−H addition process. [ABSTRACT FROM AUTHOR]

We report the development of an earth‐abundant metal catalyst for methane C−H borylation. The post‐synthetic metalation of bipyridine‐functionalized zirconium metal‐organic framework (MOF) with NiBr2, followed by treatment with NaEt3BH affords MOF‐supported monomeric bipyridyl‐nickel(II) dihydride species via active site isolation. The heterogeneous and recyclable nickel catalyst selectively borylates methane at 200 °C using pinacolborane (HBpin) to afford CH3Bpin in 61 % yield with a turnover number (TON) up to 1388. The confinement of the active NiH2‐species within the uniformly porous MOF allows selective monoborylation of methane via shape‐selective catalysis by preventing the formation of sterically encumbered overborylated products. Unlike MOF−Ni catalyst, its homogeneous control is almost inactive in methane borylation due to its intermolecular decomposition. Our mechanistic investigation, including spectroscopic, kinetic, and control experiments, as well as DFT calculations, revealed that stabilizing mononuclear bipyridyl‐nickel dihydride and diboryl species by MOF is crucial for achieving efficient methane borylation via turnover‐limiting σ‐bond metathesis. This work shows promise in designing MOF‐based abundant metal catalysts for the chemoselective functionalization of methane and other inert molecules into valuable chemicals. [ABSTRACT FROM AUTHOR]

Herein, we report an inexpensive first‐row transition metal Ni heterogeneous catalytic system for the Csp3‐mono alkylation of fluorene using alcohols as alkylating agents via borrowing hydrogen strategy. The catalytic protocol displayed versatility with high yields of the desired products using various types of primary alcohols, including aryl/hetero aryl methanols, and aliphatic alcohols as alkylating agents. The catalyst Ni NPs@N−C was synthesized via high‐temperature pyrolysis strategy, using ZIF‐8 as the sacrificial template. The Ni NPs@N−C catalyst was characterized by XPS, HR‐TEM, HAADF‐STEM, XRD and ICP‐MS. The catalyst is stable even in the air at room temperature, displayed excellent activity and could be recycled 5 times without appreciable loss of its activity. [ABSTRACT FROM AUTHOR]

BACKGROUND: One‐stage hydroconversion of fatty‐acid based feedstocks is a promising way to obtain high‐quality fuels. This process is based on hydrodeoxygenation, isomerization and hydrocracking reactions. In this work, Ni2P/Al2O3‐zeolite catalysts were synthesized and tested in hydroconversion of a model compound – methyl palmitate. RESULTS: Ni2P catalysts were prepared by in situ phosphidation of metallic Ni/Al2O3‐zeolite precursors by PPh3. Mixtures of zeolite (30 wt%) and boehmite were peptized and extruded to obtain the support granules. SAPO‐11, ZSM‐5, ZSM‐22, ZSM‐23 and ZSM‐12 were used as a zeolite component. The catalysts and supports were characterized by a range of physicochemical methods: chemical analysis (ICP‐AES), low‐temperature N2 adsorption, H2‐temperature programmed reduction, NH3‐temperature programmed desorption, Fourier transform infrared spectroscopy of adsorbed CO, X‐ray diffraction, transmission electron microscopy, X‐ray photoelectron spectroscopy, and 27Al and 31P magic angle spinning nuclear magnetic resonance. The catalysts were studied in methyl palmitate hydroconversion (one‐stage hydrodeoxygenation‐isomerization‐hydrocracking) in a continuous‐flow fixed bed reactor at 290–340 °C, 2 MPa, H2/feed = 600 Ncm3/cm3 and LHSV = 5.3 h−1. SAPO‐11 containing sample showed high selectivity to C15 and C16 iso‐alkanes (63%, at 340 °C), and all ZSM‐containing samples showed high selectivity to cracked C5–C9 products (55–100%, at 340 °C) with varying amounts of iso‐alkanes (31–57%, at 340 °C). CONCLUSION: The results show that by choosing the zeolite component of the catalyst it is possible to finely tune product quality in the range from low‐temperature diesel fuel to jet fuel or gasoline. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

BACKGROUND: The synthesis of fatty amines via fatty alcohol amination offers a promising avenue for environmentally friendly production, particularly when compared with the methods employing hydrocyanic acid which often involve significant emissions. RESULT: This study explores the synthesis of n‐hexylamine through one‐step amination of n‐hexanol utilizing a series of Ru‐doped Ni catalysts supported over γ‐Al2O3, achieving 61% n‐hexanol yield, 35% dihylamine yield and 3.5% trihylamine yield at the n‐hexanol conversion of 99%. CONCLUSION: The characterization results of the catalysts revealed a significant interaction between ruthenium and nickel in the bimetallic catalysts, leading to the enhanced reducibility of Ni species and improved metal dispersion. Moreover, ruthenium species were found to play an important role in the dissociation of NH3 into NHx (x = 1, 2), thereby significantly improving the dehydrogenation process of n‐hexanol at Ni sites. The synergistic effect between the two kinds of metal sites emerges as crucial factor for the boosted alcohols amination process. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Background: The transition from fossil-derived jet fuels to sustainable aviation fuels represents one of the most viable strategies to decarbonize air transport and mitigate CO2 emissions generated by fossil fuel combustion. In the present investigation, a catalytic hydroprocessing upgrading approach was used to transform Yellow Dodolla oil—one of the most prominent inedible Brassica carinata vegetable oils (indigenous to Ethiopia)—into bio-jet fuel. Methods: The feedstock was upgraded to jet fuel through catalytic hydroprocessing under elevated hydrogen pressure (21 bar), varying temperatures (300 and 500 °C), and employing supported carbon-coated mesoporous and crystalline nanocatalysts (β-Mo2C/AlPO4-18, Ni3C/AlPO4-18, and WC/AlPO4-18) in a laboratory-scale continuous three-phase fixed-bed reactor system. Other variables, such as the volumetric flow rate of oil feedstock, volumetric flow rate of hydrogen gas, hydrogen gas-to-oil ratio, catalyst-to-oil ratio, liquid hourly space velocity, weight hourly space velocity, and residence time, were maintained constant throughout the experimental procedure. Subsequent to an in-depth evaluation of catalytic performance parameters (conversion, selectivity, yield, and deoxygenation rate), a detailed characterization of the liquid phase products was undertaken to explore their most significant properties. Results: The analysis results demonstrated that the catalytic hydroconversion of the feedstock resulted in a conversion range of 71.57–79.76 wt.%, with the highest conversion of 79.76 wt.% achieved by Ni3C/AlPO4–18 at the maximum temperature. Moreover, the rate of deoxygenation varied from 8.08 to 11.67 wt.% at 300 °C, with nickel catalyst reaching the maximum rate, while it sharply rose to vary from 57.31 to 96.67 wt.% using molybdenum as the temperature increased to 500 °C. It was also discovered that in comparison to bio-gasoline (2.63–8.72 wt.%) and biodiesel (1.18–4.58 wt.%), bio-jet fuel (C8–C16) had noticeably higher yields (23.34–27.31 wt.%), selectivity (37–45 wt.%), and a superb hydrocarbon product distribution (C9–C16) at the maximum temperature, with WC/AlPO4-18 producing the highest yields and selectivity of jet fuel. The characterization results revealed that the hydrocracked liquid products possessed virtually identical physicochemical properties, chemical compositions, hydrogen-to-carbon atomic ratios (1.90–1.92), oxygen-to-carbon atomic ratios (0.002–0.030), and gravimetric energy densities (41.35–42.89 MJ kg−1) to those of conventional jet fuels. Conclusions: The conclusions of the study demonstrated that the non-food Yellow Dodolla oil was successfully hydrocracked into sustainable aviation fuel using AlPO4-18 supported metal carbide catalyst nanoparticles under the right reaction conditions and reactor system, potentially supporting the significant efforts of the aviation industry to lower its carbon footprint. [ABSTRACT FROM AUTHOR]

Exploring high‐performance anion exchange membranes (AEM) for water electrolyzers (AEMWEs) is significant for green hydrogen production. However, the current AEMWEs are restricted by the poor mechanical strength and low OH− conductivity of AEMs, leading to the low working stability and low current density. Here, we develop a robust AEM with polybiphenylpiperidium network by combining the crosslinking with triazine and the capping with pyridine for advanced AEMWEs. The AEM exhibits an excellent mechanical strength (79.4 MPa), low swelling ratio (19.2 %), persistent alkali stability (≈5,000 hours) and high OH− conductivity (247.2 mS cm−1) which achieves the state‐of‐the‐art AEMs. Importantly, when applied in AEMWEs, the corresponding electrolyzer equipped with commercial nickel iron and nickel molybdenum catalysts obtained a current density of up to 3.0 A cm−2 at 2 V and could be stably operated ~430 h at a high current density of 1.6 A cm−2, which exceeds the most of AEMWEs. Our results suggest that triazine crosslinking and pyridine capping can effectively improve the overall performance of the AEMWEs. [ABSTRACT FROM AUTHOR]

Serpentinizing hydrothermal vents are likely sites for the origin of metabolism because they produce H2 as a source of electrons for CO2 reduction while depositing zero‐valent iron, cobalt, and nickel as catalysts for organic reactions. Recent work has shown that solid‐state nickel can catalyze the H2‐dependent reduction of CO2 to various organic acids and their reductive amination with H2 and NH3 to biological amino acids under the conditions of H2‐producing hydrothermal vents and that amino acid synthesis from NH3, H2, and 2‐oxoacids is facile in the presence of Ni0. Such reactions suggest a metallic origin of metabolism during early biochemical evolution because single metals replace the function of over 130 enzymatic reactions at the core of metabolism in microbes that use the acetyl‐CoA pathway of CO2 fixation. Yet solid‐state catalysts tether primordial amino synthesis to a mineral surface. Many studies have shown that pyridoxal catalyzes transamination reactions without enzymes. Here we show that pyridoxamine, the NH2‐transferring intermediate in pyridoxal‐dependent transamination reactions, is generated from pyridoxal by reaction with NH3 (as little as 5 mm) and H2 (5 bar) on Ni0 as catalyst at pH 11 and 80 °C within hours. These conditions correspond to those in hydrothermal vents undergoing active serpentinization. The results indicate that at the origin of metabolism, pyridoxamine provided a soluble, organic amino donor for aqueous amino acid synthesis, mediating an evolutionary transition from NH3‐dependent amino acid synthesis on inorganic surfaces to pyridoxamine‐dependent organic reactions in the aqueous phase. [ABSTRACT FROM AUTHOR]

Integrating sulfide oxidation reaction (SOR) with hydrogen evolution reaction (HER) by electrochemical means to simultaneously valorize sulfion and produce hydrogen is an efficient cleaner production method. Currently, we reported on the fabrication of one succulent-like phosphorus-doped transition metal selenide bifunctional catalyst supported on nickel foam (P–CoSe/NF) for SOR and HER. The unique structure has a significant surface area that allows many active sites to be exposed, enabling the catalyst to have an excellent activity up to 100 mA cm−2 at only 0.362 V. The H 2 Faraday efficiency reaches 97.4% and the rate of sulfur evolution is 26.24 mg h−1. The durability test demonstrates that the bifunctional catalyst possesses excellent anti-sulfur properties. The Density Functional Theory calculations demonstrate that phosphorus as a dopant is believed to confer an optimal electronic structure and local coordination environment by tuning d electron number. The calculate S 8 ∗ to S 8 was confirmed to have a low energy barrier, indicating the self-cleaning tendency caused by phosphorus doping. This work presents a promising approach utilizing anti-sulfur single-atom-doped transition metal selenide catalysts in electrochemical reaction, representing a significant advancement in achieving low-cost and high value-added using waste resources. [Display omitted] • A new method for synthesis of succulent-like phosphorus-doped transition metal selenide catalyst. • Phosphorus doping regulates the number of d electron. • Phosphorus-doped transition metal selenide bifunctional catalyst has a self-cleaning effect. • Simultaneous S and H 2 production as a bifunctional electrode in coupled system. [ABSTRACT FROM AUTHOR]

2, 5‐Dimethylfuran (DMF), which is a promising new‐generation liquid biofuel, has attracted widespread attention owing to the sustainability of biomass‐derived energy sources. In this study, a highly dispersed zirconia‐supported nickel catalyst (CA−Ni/ZrO2) was prepared via citric acid‐assisted wetness impregnation for the selective hydrogenolysis of 5‐hydroxymethylfurfural (HMF) to produce DMF. The characterization results confirmed the presence of Zr3+ species in the mesoporous CA−Ni/ZrO2 catalyst and the formation of oxygen vacancies during its preparation, which led to the formation of a large number of catalytically active sites for the adsorption and activation of the C=O/C−O groups. Under appropriate reaction parameters, an excellent DMF selectivity of 99.1 % and an HMF conversion of 98.4 % were achieved. A suitable kinetic model revealed that DMF was preferentially formed via the 2,5‐dihydroxymethylfuran intermediate route, although a 5‐methylfurfural route was also observed. Additionally, the interaction between Ni and ZrO2 significantly affected the stability of the catalyst. This study will provide guidelines for optimizing the catalytic conversion of furan derivatives over heterogeneous catalysts. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Cross‐electrophile couplings (XEC), a crucial subset of cross‐coupling reactions, center on the formation of robust C—C bonds through the union of two electrophiles. Usually, such reactions have primarily been catalyzed by transition metals. However, with the steady advancements in photochemical and electrochemical technologies, XEC reactions have significantly progressed and broadened their scope, allowing for the utilization of a wider array of tolerable functional groups, thus revealing vast application prospects. This review aims to systematically summarize the current prevalent types of electrophiles and delve into their specific application examples within XEC reactions involving electrophiles with identical functional groups. Specifically, XECs between the same type of halides have received considerable attention, whereas carboxylic acids and alcohols are still in the early stages of investigation. Furthermore, certain other common electrophiles remain unexplored in this context. Moreover, this review underscores the remarkable contributions of photochemistry and electrochemistry in the field of XEC reactions, aiming to provide valuable insights and inspiration for researchers. Also, this review hopes to spark further interest in XEC reactions, thereby fueling the continuous development and advancement of this exciting area of research. Key Scientists: Since the 1960s, advancements in the XEC reaction have been substantial, driven primarily by the application of transition metal catalysts. In this area, many distinguished scientists have contributed their wisdom and efforts. Particularly noteworthy is that, during the systematic study of XEC reactions with the identical functional groups, in 2016, MacMillan achieved a photocatalytic XEC reaction between aryl bromides and alkyl bromides; in 2020, Weix successfully realized a nickel‐catalyzed XEC reaction between aryl chlorides and alkyl chlorides. Concurrently, contributions from researchers such as Mei, Wolf, Sevov, Lin, Shen, Browne, Zhang, and Qiu have expanded the scope of XEC reactions to various halides. By 2022, MacMillan and Baran achieved a significant milestone in the XEC between carboxylic acids, further broadening the scope of research in this area. Also, advancements in the XEC of alcohols have been noted, with researchers including Weix, Lian, Tu, and Stahl conducting pioneering work and successfully executing the XEC of protective groups. It is foreseen that the ongoing research endeavors will primarily concentrate on the expansion of diverse electrophiles. [ABSTRACT FROM AUTHOR]

The electrocatalytic conversion of carbon dioxide (CO2) into valuable multicarbon (C2+) compounds offers a promising approach to mitigate CO2 emissions and harness renewable energy. However, achieving precise selectivity for specific C2+ products, such as ethylene and ethanol, remains a formidable challenge. This study shows that incorporating elemental boron (B) into copper (Cu) catalysts provides additional adsorption sites for *CO intermediates, enhancing the selectivity of desirable C2+ products. Additionally, using a nickel single‐atom catalyst (Ni‐SAC) as a *CO source increases local *CO concentration and reduces the hydrogen evolution reaction. In situ experiments and density functional theory (DFT) calculations reveal that surface‐bound boron units adsorb and convert *CO more efficiently, promoting ethylene production, while boron within the bulk phase of copper influences charge transfer, facilitating ethanol generation. In a neutral electrolyte, the bias current density for ethylene production using the B‐O‐Cu2@Ni‐SAC0.05 hybrid catalyst exceeded 300 mA cm−2, and that for ethanol production with B‐O‐Cu5@Ni‐SAC0.2 surpassed 250 mA cm−2. This study underscores that elemental doping in Cu‐based catalysts not only alters charge and crystalline phase arrangements at Cu sites but also provides additional reduction sites for coupling reactions, enabling the efficient synthesis of distinct C2+ products. [ABSTRACT FROM AUTHOR]

Comprehensive Summary For coordination‐insertion olefin polymerization, the development of novel transition‐metal catalysts has drawn extensive attention in this field. In this contribution, we designed a series of hemilabile α‐diimine nickel catalysts bearing oxygen atom as neighboring group. The steric hindrance and oxygen atom number of these nickel complexes (Ni1—Ni4) could be adjusted, which influenced ethylene (co)polymerization processes. The introduction of oxygen atoms could enhance the thermal stability during ethylene polymerization for Ni2 compared to the counterpart without oxygen atoms. And for the copolymerization process of ethylene with polar monomers, higher catalytic activity (1.4 × 106 g·mol−1·h−1) and polar monomer incorporation ratio (1.2 mol%) were achieved. However, Ni4 with four oxygen atoms in this work was not active in ethylene polymerization due to the interaction between the oxygen atom and nickel catalytic center. The hemilabile effect in this work presented an example to enhance the stability of the α‐diimine nickel catalysts in olefin polymerization. [ABSTRACT FROM AUTHOR]

A novel and efficient one‐pot method has been developed for the synthesis of thioamides through coupling reactions between thiocarbamoyl fluorides, which are generated in situ from amines, and boronic acids. The key to the success of this transformation lies in the use of nickel a catalyst combined with PCy3 as a ligand. This innovative reaction protocol provides mild reaction conditions suitable for producing a diverse array of thioamides, and the late‐stage modification of amoxapine was successfully achieved. [ABSTRACT FROM AUTHOR]

Each step in the catalyst synthesis process plays an important role in tuning the catalyst structures. For zeolite‐supported nickel catalysts, we found the conventional calcination‐reduction method typically leads to the formation of large nickel particles, but a pre‐aging in hydrogen or nitrogen at a low temperature prior to final reduction can result in ultra‐small nickel nanoparticles in a metallic state. This pre‐aging treatment facilitates the interaction between Ni2+ cations and silanol nests on zeolite before the decomposition of the metal salt, leading to the formation of nanoparticles with an average diameter of ~1.2 nm. In contrast, the pre‐calcination in oxygen caused the Ni2+ aggregation before the decomposition of the metal salt precursor, yielding nickel nanoparticles larger than 5 nm. Given the structure sensitivity of nickel in cyclohexane dehydrogenation for hydrogen production, the ultra‐small nickel nanoparticles exhibited significantly enhanced activity and durability compared to previous nickel catalysts. [ABSTRACT FROM AUTHOR]

There is a growing interest in the development of active, durable, and cost-effective electrocatalysts for oxygen evolution reactions (OER). In this study, we synthesized a self-reconstruction iron-doped sulfide-regulated nickel molybdate catalyst using wet chemical sulfuration and electrodeposition techniques. The core-shell nanorods (SC@NMO) were produced through rapid sulfuration. We investigated the effects of sulfur leaching on rapid and extensive electrochemical self-reconstruction. Our approach utilized the phase change of Fe3+ and electrodeposition-induced restructuring to enhance the catalyst's OER activity and stability in an alkaline electrolyte. Notably, iron ions establish a precipitation-dissolution dynamic equilibrium at the interface between the catalyst surface and the electrolyte, which minimizes iron loss and results in a more efficient and stable catalyst. The prepared sample, SC-Fe(Ni)OOH@NMO, demonstrated exceptional oxygen evolution performance and long-term stability in a 1 M KOH solution, achieving an overpotential of only 279 mV at a current density of 100 mA cm−2. It maintained stable operation for 200 h in a high-concentration 6 M KOH solution. The above data prove that this work provides a feasible strategy to enhance the OER catalytic capacity of metal oxides by the two modification methods of co-doping of metal and non-metal and reconstruction. [Display omitted] • The core-shell nanorods were obtained by wet sulfuration. • The dynamic reconstruction of Fe3+ improves the catalyst's activity and stability. • SC-NiFeOOH@NMO has long-term stability in high concentration alkaline medium. [ABSTRACT FROM AUTHOR]

Here, the catalytic and degradation effect of nickel nanoparticles (NiNPs) on triethanolamine (TEA) with CO2 at 20 °C and 50 °C and a range of TEA concentrations (3–30 wt%) was studied. We show that TEA absorption rate of CO2 can be enhanced with NiNPs, the maximum enhancement was 8.3% when compared to a control solution found at 50 °C with 30 wt% TEA alone. Additionally, the time for TEA to be fully loaded with CO2 is reduced; compared to the control, NiNPs enhanced solutions were up to 26.3% faster. Also, to the best of our knowledge, this is the first time the degradation of TEA with NiNPs has been studied. TEA was subject to both oxygen (30 wt%, 55 °C, 0.35 L/min of air, 0.4 molCO2/molTEA, 7.5 mL/min of CO2) and thermal degradation with and without NiNPs (30 wt%, 0.5 molCO2/molTEA, 135 °C). In both degradation experiments, surprisingly, there was no significant difference in TEA degradation in the presence of NiNPs. At high temperature (135 °C), the solution lost 19.2% and 20.3% of the original TEA, with and without NiNPs, respectively. In the presence of oxygen, the solution lost 30.5% and 33.6% of the original TEA, with and without NiNPs, respectively. This indicates that TEA or its mixture with other amines and NiNPs could improve post-combustion CO2 capture. [ABSTRACT FROM AUTHOR]

In this work, the simple fabrication of a new superhydrophobic magnetic sponge based on CNTs, NiFe2O4 nanoparticles, and PDMS was investigated. CNTs were synthesized by chemical vapor deposition (CVD) on a nickel ferrite catalyst supported on aluminum oxide (NiFe2O4/Al2O3). The synthesis of nickel ferrite (NiFe) was accomplished using the sol–gel method, yielding magnetic nanoparticles (43 Am2kg−1, coercivity of 93 Oe, 21–29 nm). A new superhydrophobic magnetic PU/CNT/NiFe2O4/PDMS sponge was fabricated using a polyurethane (PU) sponge, CNTs, NiFe2O4 nanoparticles, and polydimethylsiloxane (PDMS) through the immersion coating method. The new PU/CNT/NiFe2O4/PDMS sponge exhibits excellent superhydrophobic/oleophilic/mechanical properties and water repellency (water absorption rate of 0.4%) while having good absorption of oil, olive oil, and organic liquids of different densities (absorption capacity of 21.38 to 44.83 g/g), excellent separation efficiency (up to 99.81%), the ability to be reused for removing oil and organic solvents for more than 10 cycles, and easy control and separation from water using a magnet. The new PU/CNT/NiFe2O4/PDMS sponge is a promising candidate as a reusable sorbent for collecting oil and organic pollutants and can also be used as a hydrophobic filter due to its excellent mechanical properties. [ABSTRACT FROM AUTHOR]

A stagnation‐flow reactor was employed to investigate the decomposition of ammonia over a Ni/Al2O3 catalyst across a range of system pressures and ammonia mole fractions. The results indicate that the system pressure has a negligible impact on the light‐off behavior and the concentration profiles of NH₃. A comparison of 1D modelling with 3D computational fluid dynamics (CFD) computations justifies the use of the simpler flow model. Good agreement between experiments and the 1D simulation is achieved for two different kinetic models from literature in the mainly diffusion‐controlled regime. For lower temperatures, at which the process is kinetically controlled, the two mechanisms exhibit significant differences. The stagnation‐flow reactor concept is shown to be a promising tool for understanding, developing, and validating the reaction kinetics of heterogeneous catalytic processes. [ABSTRACT FROM AUTHOR]

Cost-effective decarbonization and structural strengthening of carbon-containing refractory materials are crucial for the development of low-carbon steel (LCS) and ultra-low-carbon steel (ULCS) technologies. In this study, a carbonaceous-ceramic reinforcement assembly structure composed of multilayer graphenes and silicon carbide whiskers/particles (MLGs-SiC w /SiC p) has been successfully designed and fabricated. By employing three-roll milling (TRM) for low-cost exfoliation of expanded graphite (EG) into MLGs in a phenolic resin (PF) medium, we optimized the exfoliation cycles to fine-tune the morphology of MLGs. Subsequently, the catalytical solid-state conversion of PF/MLGs reacting with Si into SiC w /SiC p at 1400 °C, under varying C/Si molar ratios and catalyst contents, not only retained the structural integrity of MLGs but also embedded them within a novel SiC w /SiC p composite matrix. Our research elucidates the catalytic conversion mechanism, underscoring the significant role of nickel catalysts in promoting efficient SiC conversion. This work offers a promising pathway for developing high-performance, economical, low-carbon refractories. [ABSTRACT FROM AUTHOR]

Trying to find beneficial and effective catalysis for synthesizing biologically active and valuable 1,2,3‐triazoles is continually being studied to make the procedure more efficient, green, and eco‐friendly. The click reaction is famous in green chemistry for its high selectivity and efficiency in generating 1,2,3‐triazoles with important pharmaceutical and biological activities. 1,3‐Dipolar cycloaddition reaction of organic azides and alkynes by copper‐mediated have a great deal of attention paid to and developed to provide 1,2,3‐triazoles. However, utilizing Cu(II) species frequently requires a reducing reagent, making this approach less atom‐economic. Recently, notable progress has been made in designing and developing metal‐catalyzed click reactions to prepare 1,2,3‐triazoles. As appropriate alternatives to copper catalysts, nickel catalysts can be a good choice in click reactions. This review thoroughly studies the excellent potential of nickel catalysts in azide‐alkyne cycloaddition reactions and recommends using them as proper alternatives to traditional copper catalysts. This review can pave the path for further application of nickel catalysts in click reactions. [ABSTRACT FROM AUTHOR]

A series of novel asymmetric alkyl P‐substituted bis(phosphanyl)amine (PNP) Ph2PN (cyclopentyl) PR1R2‐type L1–L5 ligands and these corresponding Ni(II) precatalysts C1–C5 were synthesized and characterized. The structures of these complexes were confirmed by using 1H‐, 31P‐, 13C‐NMR, FT‐IR, and elemental analysis. Using ethylaluminum dichloride (EADC) as a cocatalyst, nickel complexes exhibited high activity in elective ethylene oligomerization, with the main products being dimers and a small number of trimers. Under optimized conditions of 60°C and 1.0 MPa ethylene pressure, C4, bearing a diisopropylphosphoryl group, exhibited highest catalytic activity of 1342.9 kg·g Ni−1·h−1 with 85.2% C4 and 14.8% C6 products selectivity, while C2, bearing a diethylphosphonyl group, showed catalytic activity of 596.4 kg·g Ni−1·h−1 with 88.2% C4 and 11.8% C6 product selectivity. Single crystal analysis offered a more comprehensive insight into the subtle effects of alkyl P‐substituted in the scaffold of C2 and C4 ligands on catalytic activity. Density functional theory (DFT) calculations indicated that lower energy of the LUMO in the C4A intermediate enhances the activity of ethylene oligomerization. It provides a new method for purposefully designing ligands for ethylene oligomerization with high catalytic activity. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Deuterium labelling possesses wide applications in pharmaceuticals, chemical science and materials science. Development of efficient methodologies for the synthesis of deuterium labelled compounds, especially hydrogen isotope exchange (HIE), continued to receive an impressive attention over the years. Herein, we developed a nitrogen doped nano‐scale nickel catalyst for deuterium incorporation of a variety of nitrogen heterocycles using D2O as the isotope source. The usefulness of this approach has been demonstrated by 10 g‐scale for complex pharmaceuticals. This methodology represents a practical and scalable deuteration and the air‐ and water‐stable nanocatalyst enables efficient labelling in a straightforward manner. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fe/Ni ratio and temperature have great influenced on the structure of CNTs. • DFT calculations are used to study the growth mechanism of CNTs. • The feasibility and mechanism of PVC removal by CNTs are investigated. Plastic waste pollution is the serious environmental problem, and catalytic pyrolysis of waste plastics is an effective way to solve this problem. Carbon nanotubes (CNTs) are prepared by catalytic pyrolysis of low-density polyethylene (LDPE) waste plastics by one-stage method using iron nitrate and nickel nitrate as catalyst. The growth mechanism of CNTs is analyzed in detail. TPO, XRD, SEM and Raman analyses show that increasing Ni content contributes to the production of CNTs with good morphology and high graphitization degree. While the increasing Fe content contributes to improving the yield of CNTs. The outer and inner diameters of the FeNi12-CNTs-800 are about 21 nm and 8 nm with the length of 18.9 μm, respectively. LDPE pyrolysis gases are analyzed to determine that the primary carbon source required for CNTs growth is C 2 H 4. The C 2 H 4 adsorption and decomposition processes on FeNi alloys are performed to reveal the growth mechanism of CNTs, based on density functional theory calculation. Three kinds of the growth models are proposed to explain the difference of the CNTs tubular shape. FeNi12-CNTs-800 are used to remove microplastics from wastewater due to existence of magnetic. PVC can be quickly removed from wastewater with removal of 100 % at 20 min. This study provides an effective way for recycling and treatment of waste plastic. [ABSTRACT FROM AUTHOR]

A highly stable and overall water splitting electrocatalyst (NF/FeNiP-CoP@NC) featuring porous configuration, numerous heterogeneous interfaces, obvious vacancies and doping defects, and abundant active species in a hierarchical heterostructure is reported, which is fabricated by a hydrothermal reaction-ion exchange-phosphorization technique. [Display omitted] • Hollow porous cubic FeNiP-CoP@NC loaded on nickel foam is prepared. • The NF/FeNiP-CoP@NC inherits excellent OER, HER, and OWS performance. • DFT confirms that the unique structure promotes the overall OWS performance. Multimetal phosphides derived from metal-organic frameworks (MOFs) have garnered significant interest owing to their distinct electronic configurations and abundant active sites. However, developing robust and efficient catalysts based on metal phosphides for overall water splitting (OWS) remains challenging. Herein, we present an approach for synthesizing a self-supporting hollow porous cubic FeNiP-CoP@NC catalyst on a nickel foam (NF) substrate. Through ion exchange, the reconstruction chemistry transforms the FeNi-MOF nanospheres into intricate hollow porous FeNi-MOF-Co nanocubes. After phosphorization, numerous N, P co-doped carbon-coated FeNiP-CoP nanoparticles were tightly embedded within a two-dimensional (2D) carbon matrix. The NF/FeNiP-CoP@NC heterostructure retained a porous configuration, numerous heterogeneous interfaces, distinct defects, and a rich composition of active sites. Moreover, incorporating Co and the resulting structural evolution facilitated the electron transfer in FeNiP-CoP@NC, enhancing the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) processes. Consequently, the NF/FeNiP-CoP@NC catalyst demonstrated very low overpotentials of 78 mV for OER and 254 mV for HER in an alkaline medium. It also exhibited excellent long-term stability at various potentials (@10 mA cm−2, @20 mA cm−2, and @50 mA cm−2). As an overall water splitting cell, it required only 1.478 V to drive a current density of 50 mA cm−2 and demonstrated long-term stability. Density functional theory (DFT) calculations revealed a synergistic effect between multimetal phosphides, enhancing the intrinsic OER and HER activities of FeNiP-CoP@NC. This work not only elucidates the role of heteroatom induction in structural reconstruction but also highlights the importance of electronic structure modulation. [ABSTRACT FROM AUTHOR]

Hierarchical hollow urchin-like nickel cobaltite (NiCo2O4) was synthesized using a two-step hydrothermal method. The effects of metal composition and surfactant addition on the morphology, structure, and electrochemical performance toward oxygen evolution reaction (OER) were investigated. The addition of cetyltrimethylammonium bromide (CTAB) reduced particle aggregation, resulting in a higher electrochemical active surface area and electrical conductivity. Lowering the Ni content from 1.0 to 0.25 did not alter the morphology and structure of the product to any extent. However, the crystallite size slightly increased. Among the spinels with different Ni and Co compositions, NiCo2O4 exhibited a superior OER electrocatalytic activity, achieving a 380 mV overpotential at 10 mA/cm2 current density. It also delivered a good performance in an anion exchange membrane water electrolyzer (AEMWE) using 1 M NaOH at 60 °C, reaching a current density of about 420 mA/cm2 at a cell voltage of 1.95 V. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Deuterium labelling possesses wide applications in pharmaceuticals, chemical science and materials science. Development of efficient methodologies for the synthesis of deuterium labelled compounds, especially hydrogen isotope exchange (HIE), continued to receive an impressive attention over the years. Herein, we developed a nitrogen doped nano‐scale nickel catalyst for deuterium incorporation of a variety of nitrogen heterocycles using D2O as the isotope source. The usefulness of this approach has been demonstrated by 10 g‐scale for complex pharmaceuticals. This methodology represents a practical and scalable deuteration and the air‐ and water‐stable nanocatalyst enables efficient labelling in a straightforward manner. [ABSTRACT FROM AUTHOR]

Ni, Pt, and NiPt catalysts supported on SBA-15 were synthesized, characterized, and tested in anisole hydrodeoxygenation to determine the effect of the metal's nature on the catalytic activity in the hydrogenation of the aromatic ring of anisole and hydrogenolysis of the C–O bond in the cyclohexyl methyl ether intermediate. Metal loadings in the catalysts were 5 wt% of Ni and 1 wt% of Pt. The bimetallic NiPt/SBA-15 catalyst showed the highest catalytic activity in both hydrogenation and hydrogenolysis, attributed to the promotional effect of Pt on NiO reduction and the formation of a Ni–Pt alloy with better dispersion of metal nanoparticles. [ABSTRACT FROM AUTHOR]

The catalytic asymmetric synthesis of axially chiral alkenes remains a daunting challenge due to the lower rotational barrier, especially for longer stereogenic axis (e.g. C-B axis). The asymmetric radical difunctionalization of alkynes represents an efficient strategy for these targets. Key to the success of such transformations lies in aryl-stabilized highly reactive alkenyl radical intermediates, however, it remains an elusive whether a boryl group could play a similar role. Here we report a nickel-catalyzed atroposelective radical relayed reductive coupling reaction of our designed ethynyl-azaborines with simple alkyl and aryl halides through a boron-stabilized vinyl radical intermediate. This transformation enables a straightforward access to the challenging axially chiral alkenylborons bearing a C-B axis in generally high enantioselectivity and excellent stereoselectivity. The catalytic asymmetric synthesis of axially chiral alkenes remains a challenge due to the lower rotational barrier, especially for longer stereogenic axis. Here the authors report a nickel-catalyzed atroposelective radical relayed reductive coupling reaction of ethynyl-azaborines with alkyl/aryl halides through a boron-stabilized vinyl radical intermediate. [ABSTRACT FROM AUTHOR]

The hydrogen evolution reaction in alkaline water electrolysis is facilitated through the electrodeposition of trimetallic catalyst on nickel foam using the chronoamperometry technique. Specifically, the trimetallic catalyst CoWRu@NF is deposited onto a nickel foam substrate. The catalytic performance of this trimetallic catalytic electrode for the Hydrogen Evolution Reaction (HER) is then assessed in a 1.0 M potassium hydroxide (KOH) solution. This specially designed trimetallic catalytic electrode system efficiently provides the more active sites through the Co component. Subsequently, it facilitates the reduction of protons (H+) to generate hydrogen gas using the Ru component. Tungsten acts as a co‐catalyst in the system for water dissociation promotor by removing hydroxide formed after water dissociation and preventing the deactivation of Ruthenium by certain reaction intermediates. The CoWRu@NF trimetallic catalyst demonstrates excellent activity, showcasing a low overpotential (−8 mV) to achieve a current density of (−10 mA/cm2. Additionally, it exhibits low Tafel slope values (101.2 mV dec−1), credited to the presence of cobalt and tungsten alongside Ruthenium in the catalytic system. This configuration is specifically designed to enhance the kinetics of the hydrogen‐evolving reaction. [ABSTRACT FROM AUTHOR]

The reductive amination of levulinic and 2‐acetyl benzoic acids with hydrogen and various amines proceeds efficiently in the presence of a homogeneous Ni/triphos‐catalyst. The reaction rate of the overall process is significantly enhanced using 3,3,3‐trifluoroethanol (TFE) as solvent. The optimized synthetic protocol allows for a straightforward access of >20 examples of N‐functionalized pyrrolidinones in high yields (75 % and >99 %). Upscaling to 10 mmol‐scale is demonstrated and mechanistic in situ studies revealed the presence of alkoxy‐ and hydroxylactams as crucial intermediates. [ABSTRACT FROM AUTHOR]

Non-precious metal catalysts (NPMCs) doped with nitrogen were derived from MOFs. Appropriate ligand and framework order in the precursor ensured the presence of various nitrogenous species and high surface area in the NPC, Ni-NPC, Co-NPC, and Fe-NPC electrocatalysts. Electrochemical properties of the as-prepared electrocatalysts were examined in 0.1 M KOH solution to investigate the effects of metal and doped nitrogen on the oxygen reduction reaction (ORR). The free metal electrocatalyst (NPC) displayed poor ORR activity with an onset potential of 0.87 V RHE. The presence of nickel in the Ni-NPC catalyst could not create more active sites in comparison with the NPC catalyst, while onset potential of the Co-NPC catalyst shifted to 21 mV more positive (Compare to NPC). The investigation of doping active transient metals indicated that Fe-doping could be effective. It was because of the improved ORR activity of the Fe-NPC electrocatalysts with an onset potential of 0.99 V RHE. Furthermore, in a long-term stability test, this optimum electrocatalyst could retain more than 92% of its initial current density and experienced just 57 mV loss in its half-wave potential in an accelerated degradation test. Direct ethanol fuel cell test reveals maximum power density of 19.2 mW cm−2 at ambient temperature. • New M-NPS electrocatalysts were synthesized by pyrolysis of effective MOF precursors. • The synthesized M-N-C electrocatalysts had high surface area and a variety in nitrogenous species. • The effect of the metal on the activity and stability of the M-N-C electrocatalysts was evaluated for ORR. • The sequence of the catalysts activity in ORR are: FeN x > CoN x > NiN x ∼ metal free-N x. [ABSTRACT FROM AUTHOR]

ABSTRACT Incorporating suitable promoters into nickel‐based catalysts for carbon dioxide methanation proves to be a successful strategy for enhancing catalyst structure, optimizing surface properties, mitigating deactivation, and ultimately boosting catalytic performance. This study focuses on the synthesis of Co‐modified Ni/CaCO3 catalysts using the solution combustion synthesis method. The catalytic activity of the afforded catalysts has been evaluated for CO2 methanation in a dielectric barrier discharge reactor operating at a gaseous hourly space velocity of 11,320 h−1 and an H2:CO2 ratio of 4:1. The catalyst exhibits optimal performance at a Ni:Co ratio of 13:2, achieving a CO2 conversion rate of 57.5% and CH4 selectivity of 92.4%. Characterization techniques such as X‐ray diffraction, transmission electron microscopy, X‐ray photoelectron spectroscopy, programmed temperature‐raising hydrogen reduction, carbon dioxide desorption, and in situ plasma DRIFTS are employed to evaluate the catalysts. The results indicate that the addition of Co to Ni‐based catalysts leads to an increase in moderately basic sites, thereby enhancing the catalytic activity and stability of catalysts for CO2 methanation. Notably, the combination of the plasma and the Ni–Co catalyst offers a novel pathway for CO2 methanation, featuring higher energy efficiency and superior synergistic effects compared to monometallic catalysts. [ABSTRACT FROM AUTHOR]

The aim of this work was to investigate the hydrocracking of algae oil derived from Spirulina Platensis species catalyzed with bi-component nickel-zirconia catalysts supported onto different carriers (BEA, ZSM-5 and Al2O3) in an autoclave at 320 °C for 2 h with a hydrogen pressure of 75 bar. All catalysts were prepared using the wet co-impregnation method and were characterized by H2-TPR, XRD, NH3-TPD, BET and SEM-EDS. Before reactions, catalysts were calcined at 600 °C for 4 h in a muffle furnace, then reduced with 5%H2-95%Ar reducing mixture at 500 °C, 600 °C or 700 °C for 2 h. The obtained products were analyzed and identified by HPLC and GC-MS techniques. In addition to the investigation of the support effect, the influence of the reduction temperature of catalytic systems on the catalytic activity and selectivity of the products was also examined. The activity results show that Ni-Zr systems supported on zeolites exhibited high conversion of algal oil. A gradual decrease in conversion was observed when increasing the reduction temperature of the catalyst (from 500 °C to 600 °C and 700 °C) for BEA zeolite catalysts. The reaction products contain hydrocarbons from C7 to C33 (for zeolite-supported catalysts) and C36 (for systems on Al2O3). The identified hydrocarbons mainly belong to the gasoil fraction (C14–C22). In the research, the best catalyst for the algal oil hydrocracking reaction was found to be the 5%Ni-5%Zr/BEA system reduced at 600 °C, which exhibited the second highest algal oil conversion (94.0%). The differences in catalytic activity that occur are due to the differences in the specific surface area among the supports and to differences in the acidity of the catalyst surface depending on the reduction temperature. [ABSTRACT FROM AUTHOR]

In this paper, the optimal control problem of hydrocarbons' hydrogenation was investigated in the presence of two catalysts—Nickel–Kieselguhr and Raney Nickel. This multistage chemical reaction holds significant practical importance, particularly in the production of high-density fuels. The optimal control problem was reformulated as a nonlinear global optimization problem and addressed using a modified Mind Evolutionary Computation algorithm. The proposed modifications include methods designed to ensure solution feasibility and ease of practical implementation. Using the proposed method, the performance of the two catalysts was compared under constant temperature conditions and with optimal control strategies. The results demonstrate that selecting an effective catalyst has a greater impact on the reaction's efficiency than temperature control alone, with the Raney Nickel catalyst consistently outperforming the Nickel–Kieselguhr catalyst by at least 17%. Additionally, the optimization approach was applied to identify a new set of catalyst parameters. The newly obtained catalyst parameters allowed for the improvement of the results of the Raney Nickel catalyst by 18%. The results of all numerical experiments and implementation details are described in the paper. [ABSTRACT FROM AUTHOR]

Herein, the study reports the first electrochemical nickel‐catalyzed enantioselective hydro‐arylation/alkenylation of enones in an undivided cell with low‐cost electrodes in the absence of external reductants and supporting electrolytes. Aryl bromides/iodides/triflates or alkenyl bromides are employed as electrophiles for the efficient preparation of more than 56 valuable β‐arylated/alkenylated ketones in a simple manner (up to 97% yield, 97% ee). With the advantages of electrochemistry, excellent functional group tolerance and late‐stage modification of complex natural products and pharmaceuticals made the established protocol greener and more economic. Mechanism investigation suggests that a NiI/NiIII cycle may be involved in this electro‐reductive reaction rather than metal reductant driven Ni0/NiII cycle. Overall, the efficient electrochemical activation and turnover of the nickel catalyst avoid the drawbacks posed by the employment of stoichiometric amount of sensitive metal powder reductants. [ABSTRACT FROM AUTHOR]