Bimetallic Synergy Research Articles

Enhanced single-atom cobalt layer in MAX phase for biomass electrooxidation integrated with hydrogen evolution

MAX phases have attracted considerable interest due to their structural diversities and potential applications. More than 150 MAX phases have been synthesized, especially expanding the range of A-site atoms from traditional main group elements to subgroup elements with outer layer d electronic structure. However, the functional applications for MAX phases remain somewhat limited. The A-site elements in MAX phases can amplify their inherent properties, transforming primary structural materials into multifunctional materials. As highly catalytic elements, introducing cobalt into the A-site of MAX phases can reveal surprising catalytic activities. Hence, the MAX phase with single-atom-thick cobalt layers was synthesized via an A-site alloying strategy in this work. The obtained V2(Sn2/3Co1/3)C MAX phase demonstrates efficient electrocatalysis in 5-hydroxymethylfurfural (HMF) oxidation reaction along with hydrogen evolution reaction (HER). In-situ electrochemical studies discover that HMF can prevent the self-reconstruction of MAX phase and oxygen evolution reaction (OER). The overall reaction reaches 94.4 % yield to 2,5-furandicarboxylic acid (FDCA) at 1.60 V. Density functional theory calculations suggest that the Co-Sn bimetallic synergy in the A-site promotes the reaction. This groundbreaking investigation into using MAX phases for biomass upgrading highlights their potential in green chemistry and beyond.

Cobalt/iron bimetallic oxide coated with graphitized nitrogen-doped carbon (Fe2O3-CoO@NC) derived from cobalt/iron solid complex as peroxymonosulfate (PMS) activator for efficient bensulfuron-methyl degradation

Cobalt/iron bimetallic oxide coated with graphitized nitrogen-doped carbon (Fe2O3-CoO@NC) was synthesized by convenient solid phase coordination combined with calcination method to activate PMS for the degradation of BSM. A series of Co/Fe bimetallic oxides with different metal ratios were designed and prepared to select the most efficient catalyst and Fe2O3-CoO@NC(Co:Fe = 1:1) demonstrated the highest catalytic activity and the lowest ions leaching. The reasons for high catalytic activity of Fe2O3-CoO@NC(Co:Fe = 1:1) were evaluated by a range of characterization techniques and the results showed it stemmed from higher mental content and larger current density. Complete (100%) degradation of 10 g L−1 BSM was achieved within 10 min under the conditions of 0.05 g L−1 catalyst and 0.3 mmol/L PMS dosage at 25 °C. Moreover, Fe2O3-CoO@NC(Co:Fe = 1:1) showed more excellent catalytic activity and lower ions leaching than Fe2O3, CoO and Fe2O3-CoO, indicating superior bimetallic synergy and carbon encapsulation effect. Furtherly, radical experiments and XPS analysis revealed the main active species and catalytic mechanism of the Fe2O3-CoO@NC/PMS system, respectively. Finally, the degradation pathway of BSM by Fe2O3-CoO@NC/PMS system was deduced by LC-TOF-MS. This paper is aimed to provide a new insight into the convenient preparation method for the construction of catalysts which could reach efficient removal of complex organic pollutants.

Fe/Mo bimetallic synergy system for ultra-highly efficient degradation of Rhodamine B

The traditional Fenton process, which depends on the use of Fe2+/H2O2, is constrained by the consumption of ferrous ions and the requirement for large amounts of H2O2. However, the assembly of bimetallic synergy systems with adjustable valence metal cations and enhanced dispersion of active sites has been evidenced to address these limitations. In this work, the Fe/Mo bimetallic synergy system in FexMo-CN materials is explored, utilized for the degradation of dyes with the assistance of H2O2. The cooperative effect of Fe/Mo bimetallic and the highly dispersed FeMoO4 as active sites make materials to achieve ultra-highly efficient degradation of dyes, approximately 100 % Rhodamine B (RhB) degradation within 6 min. And the corresponding degradation rate constant is 1.3471 min−1. Additionally, FexMo-CN materials exhibit excellent stability and versatility in solutions containing various cations, anions, or other dyes. Quenching experiments and EPR tests demonstrate that singlet oxygen (1O2) serves as the main reactive oxygen species (ROS) to degrade RhB. And the mechanism of generated 1O2 is revealed. The degradation path and mechanism of RhB are analyzed and the toxicology of intermediate products are calculated in detail. This work presents a novel approach for enhancing efficiency in Fenton-like reactions within the field of environmental remediation.

Facile construction of a stable biomass-derived carbon-supported AlZr composite with crystalline solid solution and Brønsted-Lewis dual acidity for efficient catalytic conversion of cellulose.

Exploiting cellulose-derived levulinic acid (LA) in biorefinery has potential application prospects, and the development of efficient and stable catalysts is crucial yet challenging. In this study, a bimetallic synergy strategy was proposed to construct an efficient and durable solid acid catalyst with crystalline solid solution by a totally solid-phase method. Mechanical activation (MA)-treated precursor (metal salts, starch, and urea) was calcined to obtain a stable biomass-derived carbon (BC)-supported AlZr (MA-AZ/BC) composite, which was applied for catalytic conversion of cellulose to LA in aqueous-phase system. The results indicate that the synergistic effect of bimetallic crystalline solid solution and the existence of Brønsted-Lewis dual-acid sites in the MA-AZ/BC catalyst contributed to a cellulose conversion efficiency of 97.5% and a LA yield of 67.1%. Benefiting from the strong bimetal-support interaction, the MA-AZ/BC catalyst exhibited favorable stability and recoverability. On the basis of comprehensive analysis, a reaction mechanism of Brønsted-Lewis dual-acid sites for synergistic catalytic conversion of cellulose was proposed. This study provides a new idea for the rational design and environmentally friendly fabrication of functional BC-based catalysts for efficiently producing platform compounds derived from biomass.

CoFe bimetallic phosphide fabricated by topological transformation strategy for efficient electrooxidation of benzyl alcohol

Rational design of effective non-precious metallic electrocatalysts is crucial for electrooxidation of benzyl alcohol (BA) producing benzoic acid (BAC). Herein, CoFe bimetallic phosphide (CoFeP-m) with bimetallic synergy, fully exposed active sites, and fast charge transfer was fabricated by topological transformation of CoFe-LDH for the efficient electrooxidation of BA to BAC under mild condition. Under the optimal conditions of starting voltage of 0.7 V vs. Ag/AgCl at 25oC, CoFeP-300 achieved 97.71% transformation of BA and 97.84% BAC's selectivity for 8 h. In addition, CoFeP-300 showed excellent stability which maintained 95.89% transform into BA and 95.37% BAC's selectivity at the sixth cycle.

The Support and Bimetallic Synergy Effects in Cu‐Ni/SiO2 Catalysts for Hydrogenation of Furfural

AbstractHerein, a series of Cu, Ni catalysts were synthesized using mesoporous SiO2 (MCM‐41) and fumed SiO2 as supports for the catalytic hydrogenation of furfural (FF). The MCM‐41 support facilitated the high dispersion of Cu, Ni nanoparticles (NPs), and the hydrogenation products are primarily in the form of alcohols. For fumed SiO2, the proper amounts of acid sites contributed to the better selectivity of 2‐methyltetrahydrofuran(2‐MTHF). Hydrogenation results showed that the 10Cu10Ni/MCM‐41 catalyst afforded a 93.6 % yield of tetrahydrofurfuryl alcohol (THFA), while the 10Cu10Ni/SiO2 catalyst afforded a 61.73 % yield of 2‐MTHF and a 31.63 % yield of THFA. Meanwhile, it is also found that impregnating nickel salt before copper salt is more likely to promote the formation of deep hydrogenation products. Cyclic experiments indicate that developing a one‐step hydrogenation process with selective production of fully hydrogenated products is still a daunting and challenging task.

(Invited) Controlled Synthesis of Cocatalyst-Semiconductor Hybrid Nanomaterials for Photocatalytic Water Splitting

With the escalating global demand for energy, mitigating anthropogenic climate change necessitates the pursuit of carbon-neutral energy sources to diminish reliance on fossil fuels. Utilizing particulate photocatalysts for solar-light-driven water splitting presents a promising and sustainable paradigm for the large-scale production of storable and clean H2 fuel. To improve the solar energy conversion efficiency, coupling the photocatalysts with cocatalysts is a broadly adopted approach not only to facilitate charge separation and transport but also to serve as reaction sites and accelerate water-splitting reactions. Recent breakthroughs in colloidal synthesis enable the fabrication of advanced nanoparticles with precise control over size and composition. Colloidal NPs represent ideal cocatalyst candidates due to their capacity to provide numerous active sites and facilitate uninterrupted light absorption by the semiconductor. Here, we introduce our approach to synthesize cocatalyst-semiconductor hybrids as efficient photocatalysts, including the alloying of platinum group metal nanoparticle cocatalysts and the control of single-atom cocatalyst locations on semiconductor nanoparticles.Platinum group metals exhibit high efficiency as cocatalysts in the hydrogen evolution reaction, attributed to their favorable catalytic and electronic properties. Bimetallic alloy systems, in general, can considerably modulate their electronic structures, resulting in exceptional physicochemical properties surpassing those of their monometallic counterparts. Herein, we synthesized PtRu solid-solution alloy nanoparticles as high-performance H2 evolution reaction cocatalysts. The rational integration of PtRu nanoparticles with Al-doped SrTiO3 photocatalyst through liquid-phase adsorption and successive two-step annealing ensure the uniform deposition of PtRu alloy nanoparticles with a solid-solution structure. The bimetallic synergy between Pt and Ru induces higher electrocatalytic activity for the hydrogen evolution reaction and a superior electron-capturing property than its Pt counterpart. Modification of Al-doped SrTiO3 with PtRu alloy nanoparticles, CrOx, and CoOOH results in efficient photocatalytic overall water-splitting activity with an apparent quantum yield of 65% at 365 nm. This work introduces a framework to elucidate catalytic trends, offering rational design guidance for the development of bimetallic solid-solution nanoparticles as highly active cocatalysts for overall water splitting.Single-atom cocatalysts dispersed on semiconductor materials exhibit outstanding heterogeneous catalytic properties through the interactions between the single atoms and the photocatalyst. The nature of these interactions depends on whether the single atoms are located on the surface or within the interior of the photocatalyst. In this work, the location-selective placement of single atoms is achieved by carefully adjusting experimental procedure. Using CdSe nanoplatelets as a support, applying different Pt precursor complexes, solvent, and workup process resulted in location selective deposition of Pt atoms outside/inside CdSe nanoplatelet support. In photocatalytic hydrogen evolution reaction, the surface-adsorbed single Pt atoms exhibit higher stability than the substituted ones. This study provides a viable strategy for the structurally precise synthesis and design of single-atom catalysts.

Pd‐Pt Bimetallic Catalysts for Enhanced Low‐Temperature Hydrodeoxygenation of Vanillin

AbstractTo make pyrolytic bio‐oil useful as a transportation fuel, the oxygen content must be reduced, and this can be carried out by using catalytic hydrodeoxygenation (HDO) reaction. The greatest challenge is associated with the removal of strongly bound oxygenated groups without saturating the aromatic ring while preserving the number of carbons. However, the development of a stable catalyst that can selectively remove such oxygenated groups with low hydrogen consumption is still challenging. In this context, a systematic study on HDO of vanillin on bimetallic Pd−Pt catalysts was carried out. It aims to study the effect of bimetallic synergy in terms of activity and selectivity to creosol. Metallic nanoparticles of Pd and Pt were synthesized by sol immobilization technique and deposited on TiO2. The conversion of vanillin was correlated to the Pd−Pt atomic ratio, while the production of the creosol was correlated to the Pd(0)/(Pd+Pt) ratio at the surface. Full conversion of vanillin was obtained at low reaction temperature (20 °C) achieving nearly 100 % selectivity to creosol. These results represent a step forward in advancing the development of more efficient and sustainable processes for bio‐oil upgrading.

Composition-engineered FeCo nanoalloys with lattice expansion and optimized electron structure boosting electrocatalytic Nitrate reduction

Herein, composition-engineered CoFe nanoalloys were in-situ constructed and confined in porous fibrous carbon by electrospinning and controlled graphitization, resulting in (110) lattice space expansion and improved free-electron-migration in nanoalloys, delivering bimetallic synergy by electron structural optimization. Impressively, the reinforced NO3- adsorption and rapid desorption of NH3 over composition-engineered nanoalloys efficiently promote the electrocatalytic dynamic behavior. As a result, the optimal Co1Fe1.5/C affords an excellent NH3 yield of 48.2 ± 1.2 mg h−1 mgcat−1 and a maximum Faraday efficiency of 90.8 ± 1.5 % at −1.1 V vs. RHE, with outstanding stability during 200 h NO3-RR, outperforming the most state-to-the-art catalysts. An excellent conversion of Nitrate (96.4 ± 0.8 %) with a high selectivity for Ammonia (94.4±1.2 %) can be validated. Detailed characterizations including in-situ XPS technique and theoretical calculation studies have demonstrated that Fe composition engineering reinforces the surface adsorption of NO3-, induces the surface electron redistribution of Co center, and optimizes the reaction pathways, resulting in the remarkable bimetallic synergy and enhancing the surface adsorption of a key intermediate of *NO over Co sites during the NO3-RR. Finally, the Zn-NO3- battery assembled by Co1Fe1.5/C was explored, which further indicates the potential of Co1Fe1.5/C in the energy conversion device.

Synergistic Catalytic Performance of Pt-Au Bimetallic Catalysts on High-Crystallinity ZSM-23 Zeolite for Hexadecane Hydroisomerization: Metal-Acid Balance and Enhanced Isomerization Selectivity.

Highly crystalline ZSM-23 zeolite, exhibiting a distinctive dumbbell morphology, was synthesized via a hydrothermal method. Bifunctional catalysts, comprising single metals (Pt or Au) and bimetals (Pt-Au), were successfully prepared by using a positional precipitation method. The hydroisomerization of hexadecane served as a model reaction to assess the catalytic performance arising from the synergistic effects of bimetallic active sites. In comparison to single-metal catalysts, 0.3Au0.7Pt/ZSM-23 demonstrated increased n-C16 conversion, while 0.5Au0.5Pt/ZSM-23 exhibited enhanced i-C16 selectivity, achieving the highest i-C16 yield. The bimetallic catalyst not only finely tuned the metal site activity through bimetallic synergy but also achieved a superior balance between metal and acid catalysis, resulting in improved catalytic performance in the n-C16 hydroisomerization. The Pt-Au bimetallic catalyst approached the ideal requirements for a hydroisomerization catalyst, achieving a harmonious balance of metal and acid catalysis.

The regulatory role of cysteine in active phase construction of polyoxometalate-based hydrodesulfurization catalysts: Reduction, chelation, and dispersion

Polyoxometalate-based hydrodesulfurization (HDS) catalysts were modified using cysteine to construct efficient CoMoS active phase. Cysteine, characterized by chelating (–COOH, –NH2) and reducing (−SH) groups, assumed a triple role in catalyst synthesis, including reduction, chelation, and dispersion. Cysteine pre-reduced polyoxometalates to heteropoly blue, significantly increasing the catalyst sulfidation. The increased nucleophilicity of heteropoly blue enhanced their attraction to Co2+ ions, intensifying the Co-Mo bimetallic synergy. The formation of Co-chelate species delayed Co sulfidation, allowing for the concurrent sulfidation of both Co and Mo species and promoting the generation of the CoMoS active phase. Carbonaceous deposits from the high-temperature carbonization of cysteine weakened the metal-support interaction, facilitating the dispersion of the active phase. The S-CoPMo12-Cys/Al2O3 catalyst demonstrated high activity in the HDS reaction of dibenzothiophene, showcasing their potential for advanced HDS reaction.

Ring-Opening Polymerization of Cyclohexene Oxide and Cycloaddition with CO2 Catalyzed by Amine Triphenolate Iron(III) Complexes.

A series of novel amine triphenolate iron complexes were synthesized and characterized using UV, IR, elemental analysis, and high-resolution mass spectrometry. These complexes were applied to the ring-opening polymerization (ROP) of cyclohexene oxide (CHO), demonstrating excellent activity (TOF > 11050 h-1) in the absence of a co-catalyst. In addition, complex C1 maintained the dimer in the presence of the reaction substrate CHO, catalyzing the ring-opening polymerization of CHO to PCHO through bimetallic synergy. Furthermore, a two-component system consisting of iron complexes and TBAB displayed the ability to catalyze the reaction of CHO with CO2, resulting in the formation of cis-cyclic carbonate with high selectivity. Complex C4 exhibited the highest catalytic activity, achieving 80% conversion of CHO at a CHO/C4/TBAB molar ratio of 2000/1/8 and a CO2 pressure of 3 MPa for 16 h at 100 °C, while maintaining >99% selectivity of cis-cyclic carbonates, which demonstrated good conversion and selectivity.

Large-area, flexible bimetallic phosphorus-based electrodes for prolong-stable industrial grade overall seawater splitting

The economical and efficient preparation of highly stable electrodes for hydrogen from water splitting is one of the current challenges. Herein, a flexible and durable bifunctional nickel–cobalt-phosphide electrode is constructed in situ on hydrophilicity filter paper (NiCoP@HP) via a one-step mild electroless plating method for industrial-scale water splitting. The bimetallic synergy of Ni-Co facilitates efficient electron transfer, while the electronegativity of phosphide contributes to high intrinsic activity, and the flexible paper substrate allow the electrode to be folded and bent. The NiCoP@HP electrodes exhibit outstanding performance for the hydrogen/oxygen evolution reaction (HER/OER), with low overpotentials only 43 mV and 164 mV at a current density of 10 mA cm−2 in simulated seawater (1.0 M KOH + 0.5 M NaCl). Importantly, the NiCoP@HP electrode demonstrates long-term stability, operating for over 1440 h at a current density of 500 mA cm−2 in 1.0 M KOH + 0.5 M NaCl and 1.0 M KOH + Seawater, respectively. This universally applicable method allows the preparation of a range of highly efficient catalytic electrodes (Fe, Mo, W, etc.). This work provides a simple, scalable, and versatile approach for the in situ construction of noble metal-free, highly efficient, and cost-effective bifunctional electrocatalysts, opening new possibilities for industrial-scale water splitting.

Tailored bimetallic synergy of iron–cobalt sulfide anchored to S-doped carbonized wood fiber for high-efficiency oxygen evolution reaction

Decoupling the scaling relation of intermediates is an effective strategy to improve the oxygen evolution reaction (OER) catalytic efficiency. Herein, S-doped carbon-confined Fe.92Co.08S nanoparticles (Fe.92Co.08S@SC) anchored to S-doped carbonized wood fiber (SCWF) are fabricated via simple synchronous carbonization and sulfidation. Due to the synergistic catalytic effect of bimetallic and the unique structural effect of the supported catalyst, Fe.92Co.08S@SC/SCWF exhibit excellent OER catalytic efficiency with an overpotential of 238 mV at 50 mA cm and stability up to 100 h. Furthermore, a high current density of 500 mA cm−2 at an overpotential of 281 mV was achieved. Theoretical calculations and electrochemical characterizations confirm that bimetallic synergies can accelerate the surface reconstruction of Fe.92Co.08S@SC with highly efficient OER activity. For zinc–air battery applications, Fe.92Co.08S@SC/SCWF exhibits superior power density and stability over commercial RuO2. This work provides insights into the preparation of supported electrocatalysts with bimetallic synergy for high-efficiency OER.

Bioinspired Binickel Catalyst for Carbon Dioxide Reduction: The Importance of Metal-ligand Cooperation.

Catalyst design for the efficient CO2 reduction reaction (CO2RR) remains a crucial challenge for the conversion of CO2 to fuels. Natural Ni-Fe carbon monoxide dehydrogenase (NiFe-CODH) achieves reversible conversion of CO2 and CO at nearly thermodynamic equilibrium potential, which provides a template for developing CO2RR catalysts. However, compared with the natural enzyme, most biomimetic synthetic Ni-Fe complexes exhibit negligible CO2RR catalytic activities, which emphasizes the significance of effective bimetallic cooperation for CO2 activation. Enlightened by bimetallic synergy, we herein report a dinickel complex, NiIINiII(bphpp)(AcO)2 (where NiNi(bphpp) is derived from H2bphpp = 2,9-bis(5-tert-butyl-2-hydroxy-3-pyridylphenyl)-1,10-phenanthroline) for electrocatalytic reduction of CO2 to CO, which exhibits a remarkable reactivity approximately 5 times higher than that of the mononuclear Ni catalyst. Electrochemical and computational studies have revealed that the redox-active phenanthroline moiety effectively modulates the electron injection and transfer akin to the [Fe3S4] cluster in NiFe-CODH, and the secondary Ni site facilitates the C-O bond activation and cleavage through electron mediation and Lewis acid characteristics. Our work underscores the significant role of bimetallic cooperation in CO2 reduction catalysis and provides valuable guidance for the rational design of CO2RR catalysts.

The Cd0.8Zn0.2S/In2S3 porous nanotubes heterojunction towards enhanced visible light photocatalytic H2 evolution and photodegradation via MOFs self-template and bimetallic synergism

The Cd0.8Zn0.2S/In2S3 porous nanotubes heterojunction is fabricated via chemical-hydrothermal method. Cd0.8Zn0.2S/In2S3 heterojunction (Cd0.8Zn0.2S/In2S3-3) exhibits a prominent enhanced photocatalytic HER activity (∼3480.91 μmol g−1 h−1, AQE of ∼12.09%) and photodegradation than single In2S3 (∼40 folds/∼10 folds) and single Cd0.8Zn0.2S (∼30 folds/∼4 folds). There, the Cd0.8Zn0.2S/In2S3 heterojunction with great potential gradient, bimetallic synergism, crystal lattice matching and visible light response can ameliorate carrier efficiency effectively, including transportation increasing, lifetime prolonging, recombination decreasing, and can be supported by the DFT. In addition, formed porous nanotubes microstructural can increase photocatalytic active sites and light reflections, and shorten carrier pathway, meanwhile maintaining a good stability. Herein, the modification of heterojunction, bimetallic synergy and hollow tubular structure can provide new sights for preparing green energy-environmental materials.

Bimetallic Synergy Enables Silole Insertion into THF and the Synthesis of Erbium Single‐Molecule Magnets

AbstractThe potassium silole K2[SiC4‐2,5‐(SiMe3)2‐3,4‐Ph2] reacts with [M(η8‐COT)(THF)4][BPh4] (M=Er, Y; COT=cyclo‐octatetraenyl) in THF to give products that feature unprecedented insertion of the nucleophilic silicon centre into a carbon‐oxygen bond of THF. The structure of the major product, [(μ‐η8 : η8‐COT)M(μ‐L1)K]∞ (1M), consists of polymeric chains of sandwich complexes, where the spiro‐bicyclic silapyran ligand [C4H8OSiC4(SiMe3)2Ph2]2− (L1) coordinates to potassium via the oxygen. The minor product [(μ‐η8 : η8‐COT)M(μ‐L1)K(THF)]2 (2M) features coordination of the silapyran to the rare‐earth metal. In forming 1M and 2M, silole insertion into THF only occurs in the presence of potassium and the rare‐earth metal, highlighting the importance of bimetallic synergy. The lower nucleophilicity of germanium(II) leads to contrasting reactivity of the potassium germole K2[GeC4‐2,5‐(SiMe3)2‐3,4‐Me2] towards [M(η8‐COT)(THF)4][BPh4], with intact transfer of the germole occurring to give the coordination polymers [{η5‐GeC4(SiMe3)2Me2}M(η8‐COT)K]∞ (3M). Despite the differences in reactivity induced by the group 14 heteroatom, the single‐molecule magnet properties of 1Er, 2Er and 3Er are similar, with thermally activated relaxation occurring via the first‐excited Kramers doublet, subject to effective energy barriers of 122, 80 and 91 cm−1, respectively. Compound 1Er is also analysed by high‐frequency dynamic magnetic susceptibility measurements up to 106 Hz.

Bimetallic Synergy Enables Silole Insertion into THF and the Synthesis of Erbium Single-Molecule Magnets.

The potassium silole K2 [SiC4 -2,5-(SiMe3 )2 -3,4-Ph2 ] reacts with [M(η8 -COT)(THF)4 ][BPh4 ] (M=Er, Y; COT=cyclo-octatetraenyl) in THF to give products that feature unprecedented insertion of the nucleophilic silicon centre into a carbon-oxygen bond of THF. The structure of the major product, [(μ-η8 : η8 -COT)M(μ-L1 )K]∞ (1M ), consists of polymeric chains of sandwich complexes, where the spiro-bicyclic silapyran ligand [C4 H8 OSiC4 (SiMe3 )2 Ph2 ]2- (L1 ) coordinates to potassium via the oxygen. The minor product [(μ-η8 : η8 -COT)M(μ-L1 )K(THF)]2 (2M ) features coordination of the silapyran to the rare-earth metal. In forming 1M and 2M , silole insertion into THF only occurs in the presence of potassium and the rare-earth metal, highlighting the importance of bimetallic synergy. The lower nucleophilicity of germanium(II) leads to contrasting reactivity of the potassium germole K2 [GeC4 -2,5-(SiMe3 )2 -3,4-Me2 ] towards [M(η8 -COT)(THF)4 ][BPh4 ], with intact transfer of the germole occurring to give the coordination polymers [{η5 -GeC4 (SiMe3 )2 Me2 }M(η8 -COT)K]∞ (3M ). Despite the differences in reactivity induced by the group 14 heteroatom, the single-molecule magnet properties of 1Er , 2Er and 3Er are similar, with thermally activated relaxation occurring via the first-excited Kramers doublet, subject to effective energy barriers of 122, 80 and 91 cm-1 , respectively. Compound 1Er is also analysed by high-frequency dynamic magnetic susceptibility measurements up to 106 Hz.

P-bridged Fe-X-Co coupled sites in hollow carbon spheres for efficient hydrogen generation

Non-precious metals have shown attractive catalytic prospects in hydrogen production from ammonia borane hydrolysis. However, the sluggish reaction kinetics in the hydrolysis process remains a challenge. Herein, P-bridged Fe-X-Co coupled sites in hollow carbon spheres (Fe-CoP@C) has been synthesized through in situ template solvothermal and subsequent surface-phosphorization. Benefiting from the optimized electronic structure induced by Fe doping to enhance the specific activity of Co sites, bimetallic synergy and hollow structure, the as-prepared Fe-CoP@C exhibits superior performances with a turnover frequency (TOF) of 183.5 min−1, and stability of over 5 cycles for ammonia borane hydrolysis, comparable to noble metal catalysts. Theoretical calculations reveal that the P-bridged Fe-X-Co coupled sites on the Fe-CoP@C catalyst surfaces is beneficial to adsorb reactant molecules and reduce their reaction barrier. This strategy of constructing hollow P-bridged bimetallic coupled sites may open new avenues for non-precious metal catalysis.

Application of 3D hierarchical porous NiCo-spinel nanosheet array for enhancement of synergistic activation of peroxymonosulfate: Degradation, Intermediates, mechanism and degradation pathway of tetracycline

The rational design of the morphology and structure of bimetallic-based heterogeneous Fenton-like catalyst derived from metal-organic-frameworks (MOFs) for peroxymonosulfate (PMS) activation via a non-radical pathway is attractive but challenging. Herein, a spinel-type 3D hierarchical porous NiCo2O4 nanosheet array for the activation of PMS is rationally designed by surfactant-assisted interfacial engineering. The experimental results showed that the NiCo2O4/PMS system demonstrated remarkable oxidative degradation of tetracycline (TC) through 1O2 attack and electron transfer process. In literature, it was thought that the PMS activation process in above system is dominated by radical pathway. In this work, we employ surfactant modified-nanostructure engineering to design hierarchical mesoporous nanosheet array structures and combined them with intrinsic bimetallic synergy to enhance catalytic activity, and interestingly the strategy transformed the PMS activation pathway into a nonradical (1O2 and electron transfer)-dominated process. This is benefit from the favorable morphological and electronic structure of the designed catalysts to facilitate mass transfer and electron transfer processes. The system also possessed a broad spectrum for degrading other typical contaminants, and was effective in tolerating actual water matrix and pH changes, as well as resisting interference from anions and organic matter. Furthermore, the robust stability of the structure and catalytic activity make it promising for practical water treatment. It can be expected that this proposal will provide insights for the delicate structural design and the understanding of its PMS activation mechanism of bimetallic-based Fenton-like catalysts, as well as for the efficient degradation of emerging organic pollutants.