Search Results (130)

In the last decades, numerous approaches have been explored for the cross-coupling of biaryl building blocks depending on the presence of boron sources. In fact, these changes have been catalyzed by transition metal complexes. This review focuses on the progress of the last decade in transition metal-catalyzed C–X borylation and direct C–H borylation, with emphasis on nickel-catalyzed C–H borylation, as effective and affordable protocols for the borylation of aryl substrates. In addition, Suzuki-type cross-coupling by activation of C–H, C–C, or C–N bonds is also reported. This study then offers an overview of recent advances for the synthesis of bi- and multi-aryls found in synthetic molecular complexes and natural products using the transition metal-catalyzed one-pot Miyaura-type C–X and C–H borylation–Suzuki coupling sequence. Full article

Density functional theory calculations were performed to elucidate the mechanistic details and origins of the selectivity of the nickel-catalyzed hydroboration of vinylarenes using B₂pin₂/MeOH. The catalytic cycles involved four sequential elementary steps: hydronickelation, anion exchange, transmetalation, and reductive elimination. Kinetic analyses identified hydronickelation as the rate-determining step with an activation barrier of 19.8 kcal/mol, while transmetalation proceeded through a stepwise mechanism characterized by two distinct transition states. Comprehensive analyses of the relevant transition structures and energetics demonstrated that the observed R-enantioselectivity (94% ee) originated from favorable nonbonding interactions. Lastly, our calculations suggested that the Markovnikov regioselectivity was predominantly governed by steric factors rather than electronic effects. Full article

Electro-oxidation of urea (UOR) in alkaline medium is one of the most effective alternative ways of producing green hydrogen, as the oxidation potential in UOR is less and thermodynamically more favorable than conventional water oxidation. The development of cost-effective materials in catalyzing UOR is recently seeking more attention in the research hotspot. Suitably modifying the Ni-based catalysts towards active site creation and preventing surface passivation is much important in this context, following which we reported the synthesis of Ni₃S₂ (NS) supported with CuCo (CC) bimetallic (NSCC). A simple hydrothermal route for NS synthesis and the electrodeposition method for CuCo (CC) deposition is adapted in a self-supported manner. The NS and CC catalysts exhibited sheet-like morphology, as confirmed by SEM and TEM analysis. The bimetallic CC deposition prevented the surface passivation of nickel sulfide (NS) over oxygen evolution reaction (OER) and improved the charge-transfer kinetics. The NSCC catalyst catalyzed UOR in an alkaline medium, which required a lower potential of 1.335 V vs. RHE to attain the current density of 10 mAcm⁻², with a lower Tafel slope value of 131 mVdec⁻¹. In addition, a two-electrode cell setup is constructed with an operating cell voltage of 1.512 V for delivering 10 mAcm⁻² current density. This study illustrates the new strategy of designing heterostructure catalysts for electrocatalytic UOR. Full article

Cocktail-type catalysis represents a significant shift in the understanding of catalytic processes, recognizing that multiple interconverting species—such as metal complexes, clusters, and nanoparticles—can coexist and cooperate within a single reaction environment. Originating from mechanistic studies on palladium-catalyzed systems, this concept challenges the classical division between homogeneous and heterogeneous catalysis. Instead, it introduces a dynamic framework where catalysts adapt and evolve under reaction conditions, often enhancing efficiency, selectivity, and durability. Using advanced spectroscopic, microscopic, and computational techniques, researchers have visualized the formation and transformation of catalytic species in real time. The cocktail-type approach has since been extended to platinum, nickel, copper, and other transition metals, revealing a general principle in catalysis. This approach not only resolves long-standing mechanistic inconsistencies, but also opens new directions for catalyst design, green chemistry, and sustainable industrial applications. Embracing the complexity of catalytic systems may redefine future strategies in both fundamental research and applied catalysis. Full article

The development of earth-abundant nickel-based catalysts is currently one of the greatest challenges for the straightforward synthesis of functionalized polyolefins. With environmental protection concerns, controllable copolymerizations of ethylene with biosourced comonomers derived from castor oil, such as methyl 10-undecenoate (U-COOMe), 10-undecen-1-ol (U-OH), or 10-undecenyl bromide (U-Br), were realized using α-diimine nickel catalyst (Ni-DBB) with dibenzobarrelene backbone. Catalyst Ni-DBB was highly tolerant toward polar comonomers, and functional polyethylenes were successfully prepared. The influences of the polar group, temperature, and comonomer concentration were studied in detail. Catalyst Ni-DBB was able to catalyze the copolymerization of ethylene with U-OH to afford high-molecular-weight (~180 kg/mol) functional polyethylene in a controlled fashion. NMR analysis showed that the produced functional polyethylenes were highly branched and had broad melting peaks ranging from 0 to 30 °C. Water contact angle (WCA) measurements showed that the surface of the obtained hydroxyl-functionalized polyethylene changed from hydrophobic to hydrophilic with the introduction of the comonomer U-OH. Full article

An efficient Ni-catalyzed, Mn-mediated denitrogenative cross-electrophile coupling of N-alkyl-1,2,3-benzotriazinones with alkyl tosylates and mesylates for access to o-alkyl secondary benzamides is reported. The method uses inexpensive non-anhydrous dimethyl acetamide (DMA) in combination with tetrabutyl ammonium iodide (TBAI) as a co-catalyst to convert sulfonates into iodides in situ. Scope and limitations of the protocol have been demonstrated by >30 examples with yields up to 91%, showing a large electronic effect from the N-substituent in benzotriazinones. An unexpected steric acceleration has been observed from the core of benzotriazinones, not only promising a highly efficient access to 2-alkyl-2,3-disubstituted benzamides but also shedding light on the rate-limiting steps in the catalytic cycle. Full article

The development of efficient, sustainable, and cost-effective catalysts is crucial for energy storage technologies, such as zinc–air batteries (ZABs). These batteries require bifunctional catalysts capable of efficiently and selectively catalyzing oxygen redox reactions. However, the high cost and low selectivity of conventional catalysts hinder the large-scale integration of ZABs into the electric grid. This study presents binder-free Fe-based bifunctional electrocatalysts synthesized via a sol–gel method, followed by thermal treatment under ammonia flow. Supported on nickel foam, the catalyst exhibits enhanced activity for both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), essential for ZAB operation. This work addresses two critical challenges in the development of ZABs: first, the replacement of costly cobalt or platinum-group-metal (PGM)-based catalysts with an efficient alternative; second, the achievement of prolonged battery performance under real conditions without passivation. Structural analysis confirms the integration of iron nitrides, oxides, and carbon, resulting in high conductivity and catalytic stability without relying on precious or cobalt-based metals. Electrochemical tests reveal that the catalyst calcined at 800 °C delivers superior performance, achieving a four-electron ORR mechanism and prolonged operational life compared to its 900 °C counterpart. Both catalysts outperform conventional Pt/C-RuO₂ systems in stability and selective bifunctionality, offering a more sustainable and cost-effective alternative. The innovative combination of nitrogen, carbon, and iron compounds overcomes limitations associated with traditional materials, paving the way for scalable, high-performance applications in renewable energy storage. This work underscores the potential of transition metal-based catalysts in advancing the commercial viability of ZABs. Full article

Microbial fuel cells (MFCs) are a novel bioenergy technology that utilizes microorganisms to catalyze the conversion of fuels into electricity. However, traditional MFCs are constrained by the low electricity generation capacity of microorganisms, resulting in relatively low power output. Additionally, the inability of traditional MFCs to store electricity significantly limits their practical applications. In this study, we fabricate a novel oxide graphite/nickel cobalt oxide (GO/NiCo₂O₄) capacitive composite bioanode material supported on stainless-steel fiber felt (SSFF). This composite material combines the excellent biocompatibility of graphite oxide and the energy storage capacity of nickel cobalt oxide. Consequently, the prepared anode exhibits significant advantages, including high specific capacitance, efficient electron transport, and enhanced biocompatibility. The MFC with the SSFF/GO/NiCo₂O₄ anode demonstrated a significantly enhanced power density, achieving a maximum of 1267.5 mW/m²—1.38-fold and 2.23-fold higher than those of the SSFF/GO and SSFF anodes, respectively. Moreover, the modified anode (SSFF/GO/NiCo₂O₄) exhibited a stored charge (Q_s) of 1405.35 C/m², representing 2.61-fold and 35.79-fold increases compared to the SSFF/GO and SSFF anodes, respectively. High-throughput analysis revealed that SSFF/GO/NiCo₂O₄-modified anode achieved an electrogenic bacterial efficiency exceeding 81%, which was significantly higher than that of the SSFF/GO and SSFF anodes. The results of this study not only provide valuable insights and theoretical guidance for the development of MFCs using capacitive composite anode materials, they also present sustainable power solutions for low-power electronic systems, such as miniaturized sensors and IoT devices. Full article

Gasification of lignocellulosic biomass has been widely highlighted as one of the most robust and promising low-carb approaches toward sustainable energy production. The gasification syngas obtained from agro-industrial residues can produce heat, power, biohydrogen, and other drop-in biofuels via F-T (Fischer-Tropsch) synthesis. However, the tar formation during the thermochemical process imposes severe limitations on the commercial scale of this technology. Tar elimination is a critical step for avoiding damage to equipment and not restricting the further application of syngas. In this context, this work sheds light on the biomass gasification field and reviews some aspects of tar formation and technologies for its reduction and removal. The approaches for dealing with tar are primary methods, which suppress or remove tar within the gasifier, and secondary methods, which remove tar in post-operation treatment. Catalytic reforming offers the most cost-effective pathway to removing tar. The bimetallic combination of nickel with other metals and using biochar as support have been intensely investigated, showing excellent tar conversion capacity. Recent research has provided new trends in non-thermal plasma-catalyzed biomass tar reforming. Future studies should focus on the integration of catalysts with multiple techniques to improve efficiency and reduce energy consumption. Full article

Microplastic pollution represents a significant global environmental issue, with cigarette filters being a major contributor due to their slow biodegradation. To address this issue while creating valuable materials, we developed a novel approach to synthesize nitrogen-doped carbon nanotubes on carbonized cigarette filter powder (NCNT@cCFP) using a microwave irradiation and nickel-catalyzed process. The successful incorporation of nitrogen (~6.6 at.%) and the enhanced graphitic structure create a hierarchical conductive network with abundant active sites for electrochemical reactions. The resulting NCNT@cCFP electrode exhibits a specific capacitance of 452 F/g at 1 A/g in a three-electrode configuration. The integrated hierarchical structure facilitates efficient electron transport and ion diffusion, leading to excellent rate capability (91.6% at 10 A/g) and cycling stability (96.5% retention after 5000 cycles). Furthermore, a symmetric supercapacitor device demonstrates promising energy storage capability with a maximum energy density of 14.0 Wh/kg at 483.1 W/kg, while maintaining 10.4 Wh/kg at a high power density of 4419.1 W/kg. This synergistic waste recycling strategy combined with microwave-driven synthesis offers a sustainable pathway for developing high-performance energy storage materials. Full article

Microwave-assisted catalytic oxidation (MACO) is a novel wastewater treatment technology for the efficient treatment degradation of organic wastewater. However, a single carbon material or SiC has limited absorption of electromagnetic waves, and the efficiency of using it as a microwave-assisted organic catalyst is not satisfactory. To improve the absorption and microwave-assisted degradation performance of carbon matrix composites, a new carbon magnetic composite Ni@SiC/CNT/CNF microwave catalyst is constructed. By controlling the introduction of nickel, different numbers of carbon nanotubes are grown on the surface of carbon nanofibers, and C and SiC double-shell structures were formed on the top of the carbon nanotubes, which catalyzed the generation of active groups by the thermal effect generated by the plasma discharge under the action of microwave field, thus realizing the highly efficient catalytic degradation of wastewater dyes. The results show that the Ni@SiC/CNT/CNF with the lowest reflection loss of RL_min = −9.26 dB exhibit excellent degradation capabilities with a degradation efficiency of 99.9% for methylene blue within 90 s under 450 W microwave irradiation. Full article

The emergence of RNA viruses driven by global population growth and international trade highlights the urgent need for effective antiviral agents that can inhibit viral replication. Nucleoside analogs, which mimic natural nucleotides, have shown promise in targeting RNA-dependent RNA polymerases (RdRps). Starting from protected 5-iodouridine, we report the synthesis of hitherto unknown C5-substituted-(1,3-diyne)-uridines nucleosides and their phosphoramidate prodrugs. The modifications at C5 include 4-(trifluoromethyl)benzene (a), 4-pentyl-benzene (b), 3,5-dimethoxy-benzene (c), 4-(trifluoromethoxy)benzene (d), 3-aniline (e), 4-pyridine (f), 3-thiophene (g), C₆H₁₃ (h), 2-pyrimidine (i), cyclopropyl (j), and phenyl (k) groups. These compounds were synthesized using Sonogashira palladium-catalyzed reactions and nickel–copper-catalyzed C-H activation between various alkynes, yielding between 25% and 67%. The antiviral activities of obtained compounds were measured through HTS against RNA viruses including influenza H1N1 and H3N2, human respiratory syncytial virus (RSV), SARS-CoV-2, Zika, hepatitis C virus (HCV), Hepatitis E virus (HEV), as well as against coronavirus (HCoV-229E). Unfortunately, none of them showed promising antiviral activity, with less than 85% inhibition observed in the cell viability screening of infected cells. Full article

Nitriles are valuable compounds because they have widespread applications in organic chemistry. This report details the nickel-catalyzed reductive cyanation of aryl halides and epoxides with cyanogen bromide for the synthesis of nitriles. This robust protocol underscores the practicality of using a commercially available and cost-effective cyanation reagent. A variety of aryl halides and epoxides featuring diverse functional groups, such as -TMS, -Bpin, -OH, -NH₂, -CN, and -CHO, were successfully converted into nitriles in moderate-to-good yields. Moreover, the syntheses at gram-scale and application in late-stage cyanation of natural products and drugs reinforces its potentiality. Full article

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. Full article

Tandem alkali-catalyzed hydrolysis and alkaline electrolysis have gradually become appealing avenues for the reformation of polyester plastics into high-value-added chemicals and green hydrogen with remarkable environmental and economic benefits. In this study, an electrochemical upcycling strategy was developed for the electrocatalytic oxidation of polylactic acid (PLA) hydrolysate into valued C₂ chemicals (i.e., acetate) and hydrogen fuel using N, P-doped CuO_x nanowires (NW) supported on nickel foam (NF) as the electrocatalyst. This 3D well-integrated catalyst was easily prepared from a Cu(OH)₂ NW/NF precursor with Saccharomycetes as a green and safe P and N source. The electrocatalyst can efficiently catalyze the lactate monomer derived from the hydrolysis of PLA waste to acetate with high selectivity and exhibits a lower onset potential for the lactate oxidation reaction (LOR) than for water oxidation, saving 224 mV to deliver a current density of 30 mA/cm². The experimental results reveal that the plausible pathway of the LOR on these CuO_x NW involves oxidation and subsequent decarboxylation. Divalent copper species have been verified to be active sites for LOR via in situ Raman spectroscopy. Full article