Promoting CO2 Electroreduction to Multi-Carbon Products by Hydrophobicity-Induced Electro-Kinetic Retardation

Advancing the performance of the Cu-catalyzed electrochemical CO₂ reduction reaction (CO₂RR) is crucial for its practical applications. Still, the wettable pristine Cu surface often suffers from low exposure to CO₂, reducing the Faradaic efficiencies (FEs) and current densities for multi-carbon (C₂₊) products. Recent studies have proposed that increasing surface availability for CO₂ by cation-exchange ionomers can enhance the C₂₊ product formation rates. However, due to the rapid formation and consumption of *CO, such promotion in reaction kinetics can shorten the residence of *CO whose adsorption determines C₂₊ selectivity, and thus the resulting C₂₊ FEs remain low. Herein, we discover that the electro-kinetic retardation caused by the strong hydrophobicity of quaternary ammonium group-functionalized polynorbornene ionomers can greatly prolong the *CO residence on Cu. This unconventional electro-kinetic effect is demonstrated by the increased Tafel slopes and the decreased sensitivity of *CO coverage change to potentials. As a result, the strongly hydrophobic Cu electrodes exhibit C₂₊ Faradaic efficiencies of ≈90 % at a partial current density of 223 mA cm⁻², more than twice of bare or hydrophilic Cu surfaces.     

The Highly Controlled and Efficient Polymerization of Ethylene

The highly controlled and efficient polymerization of ethylene is a very attractive but challenging target. Herein we report on a Coordinative Chain Transfer Polymerization catalyst, which combines a high degree of control and very high activity in ethylene oligo- or polymerization with extremely high chain transfer agent (triethylaluminum) to catalyst ratios (catalyst economy). Our Zr catalyst is long living and temperature stable. The chain length of the polyethylene products increases over time under constant ethylene feed or until a certain volume of ethylene is completely consumed to reach the expected molecular weight. Very high activities are observed if the catalyst elongates 60 000 or more alkyl chains and the polydispersity of the strictly linear polyethylene materials obtained are very low. The key for the combination of high control and efficiency seems to be a catalyst stabilized by only one strongly bound monoanionic N-ligand.     

Regulation of Atomic Fe-Spin State by Crystal Field and Magnetic Field for Enhanced Oxygen Electrocatalysis in Rechargeable Zinc-Air Batteries

Highly-active and low-cost bifunctional electrocatalysts for oxygen reduction and evolution are essential in rechargeable metal-air batteries, and single atom catalysts with Fe−N−C are promising candidates. However, the activity still needs to be boosted, and the origination of spin-related oxygen catalytic performance is still uncertain. Herein, an effective strategy to regulate local spin state of Fe−N−C through manipulating crystal field and magnetic field is proposed. The spin state of atomic Fe can be regulated from low spin to intermediate spin and to high spin. The cavitation of d_xz and d_yz orbitals of high spin Fe^III can optimize the O₂ adsorption and promote the rate-determining step (*O₂ to *OOH). Benefiting from these merits, the high spin Fe−N−C electrocatalyst displays the highest oxygen electrocatalytic activities. Furthermore, the high spin Fe−N−C-based rechargeable zinc-air battery displays a high power density of 170 mW cm⁻² and good stability.     

Engineering Heterogeneous Catalysis with Strong Metal–Support Interactions: Characterization,Theory and Manipulation

Strong metal–support interactions (SMSI) represent a classic yet fast-growing area in catalysis research. The SMSI phenomenon results in the encapsulation and stabilization of metal nanoparticles (NPs) with the support material that significantly impacts the catalytic performance through regulation of the interfacial interactions. Engineering SMSI provides a promising approach to steer catalytic performance in various chemical processes, which serves as an effective tool to tackle energy and environmental challenges. Our Minireview covers characterization, theory, catalytic activity, dependence on the catalytic structure and inducing environment of SMSI phenomena. By providing an overview and outlook on the cutting-edge techniques in this multidisciplinary research field, we not only want to provide insights into the further exploitation of SMSI in catalysis, but we also hope to inspire rational designs and characterization in the broad field of material science and physical chemistry.     

Cooperative Ni(Co)-Ru-P Sites Activate Dehydrogenation for Hydrazine Oxidation Assisting Self-powered H2 Production

Water electrolysis for H₂ production is restricted by the sluggish oxygen evolution reaction (OER). Using the thermodynamically more favorable hydrazine oxidation reaction (HzOR) to replace OER has attracted ever-growing attention. Herein, we report a twisted NiCoP nanowire array immobilized with Ru single atoms (Ru₁−NiCoP) as superior bifunctional electrocatalyst toward both HzOR and hydrogen evolution reaction (HER), realizing an ultralow working potential of −60 mV and overpotential of 32 mV for a current density of 10 mA cm⁻², respectively. Inspiringly, two-electrode electrolyzer based on overall hydrazine splitting (OHzS) demonstrates outstanding activity with a record-high current density of 522 mA cm⁻² at cell voltage of 0.3 V. DFT calculations elucidate the cooperative Ni(Co)−Ru−P sites in Ru₁−NiCoP optimize H* adsorption, and enhance adsorption of *N₂H₂ to significantly lower the energy barrier for hydrazine dehydrogenation. Moreover, a self-powered H₂ production system utilizing OHzS device driven by direct hydrazine fuel cell (DHzFC) achieve a satisfactory rate of 24.0 mol h⁻¹ m⁻².     

Non-Interacting Ni and Fe Dual-Atom Pair Sites in N-Doped Carbon Catalysts for Efficient Concentrating Solar-Driven Photothermal CO2 Reduction

Solar-to-chemical energy conversion under weak solar irradiation is generally difficult to meet the heat demand of CO₂ reduction. Herein, a new concentrated solar-driven photothermal system coupling a dual-metal single-atom catalyst (DSAC) with adjacent Ni−N₄ and Fe−N₄ pair sites is designed for boosting gas-solid CO₂ reduction with H₂O under simulated solar irradiation, even under ambient sunlight. As expected, the (Ni, Fe)−N−C DSAC exhibits a superior photothermal catalytic performance for CO₂ reduction to CO (86.16 μmol g⁻¹ h⁻¹), CH₄ (135.35 μmol g⁻¹ h⁻¹) and CH₃OH (59.81 μmol g⁻¹ h⁻¹), which are equivalent to 1.70-fold, 1.27-fold and 1.23-fold higher than those of the Fe−N−C catalyst, respectively. Based on theoretical simulations, the Fermi level and d-band center of Fe atom is efficiently regulated in non-interacting Ni and Fe dual-atom pair sites with electronic interaction through electron orbital hybridization on (Ni, Fe)−N−C DSAC. Crucially, the distance between adjacent Ni and Fe atoms of the Ni−N−N−Fe configuration means that the additional Ni atom as a new active site contributes to the main *COOH and *HCO₃ dissociation to optimize the corresponding energy barriers in the reaction process, leading to specific dual reaction pathways (COOH and HCO₃ pathways) for solar-driven photothermal CO₂ reduction to initial CO production.     

甲烷氧化偶联Ti-La-Li系混合氧化物催化剂

研究了Ti-La-Li三元氧化物的组成、结构及其对甲烷氧化偶联反应的催化性能；用XRD、IR、XPS和SEM等方法对催化剂进行表征，结果表明：在LiTi_xLa_(1-x)O_2系列催化剂中，随x值的不同，可生成LaTi_(1－y)Li_yO_(3-λ)、Li_2TiO_3、La_(0.66)TiO_(2.993)、La_2O_3和Li_(1.33)Ti_(1.66)O_4几种物相，其中，钙钛矿到三元复合氧化物LaTi_(1-y)Li_yO_(3-λ)是甲烷氧化偶联反应的主要活性相，活性位Li~＋-O~－-Ti~(3＋)的形成是活性提高的主要原因．Li_2TiO_3和La_(0.66)TiO_(2.993)是深度氧化活性相，而Li_(1.33)Ti_(1.66)O_4既无偶联活性，也无深度氧化活性．     

高性能质子交换膜燃料电池

用全氟碘酸质子交换膜作为质子交换膜燃料电池（ＰＥＭＦＣ）电解质,简化了水和电解质的管理。本文研究了该燃料电池质子交换膜厚度对电池性能影响;性能最佳的Ｎａｆｉｏｎ１１２膜和低铂载量Ｅ－ＴＥＫ电极组装的ＰＥＭＦＣ,在输出功率高达０．９５Ｗ／ｃｍ＾２;同时考察了电池的能量转换效率、Ｅ－ＴＥＫ电极中铂电催化剂利用率和电池的稳定性。     

Selective oxidation of alkenes catalysed by ruthenium(II) complexes containing coordinated perchlorate

Ruthenium(II) perchlorate complexes, [Ru(dppm)₃(ClO₄)]ClO₄ 1, [Ru(dppe)₃(ClO₄)]ClO₄ 2, and [Ru(dpae)₃(ClO₄)]ClO₄ 3, catalyse the selective homogeneous oxidation of alkenes with TBHP and H₂O₂ as oxidizing agents. Oxidation of cyclohexene with TBHP gave 2-cyclohexene-1-ol, 2-cyclohexenone and 1-(tert-butylperoxy)-2-cyclohexene. The homogeneous liquid phase oxidation of cyclohexene with TBHP shows appreciable solvent effect. Styrene on oxidation with TBHP gave benzaldehyde as the major product and styrene oxide as the minor product. Oxidation with H₂O₂ is radical-initiated and gives low conversion to products. TBHP and H₂O₂ are compared for their oxidizing ability and TBHP is more effective than H₂O₂ as an oxidizing agent. Linear and long chain alkenes are not efficiently oxidized. Cyclooctene and trans-stilbene are oxidized to the corresponding epoxides.     

硅氢加成反应高选择性合成甲基苯乙基二氯硅烷

研究了硅胶负载聚乙二醇铂催化苯乙烯与甲基二氯氢硅的硅氢加成反应,β-加成产物甲基苯乙基二氯硅烷的选择性为100%,10℃下反应8h苯乙烯转化率为96.0%.反应存在一个诱导期,温度等反应参数对诱导期有重要影响,40℃下反应的诱导期不到1h,并探讨催化剂的催化机理和目标产物高选择性的原因.