Nature Catalysis最新文献

Alkane dehydrogenation as a direct route to produce olefins receives widespread attention from industry and academia. However, high temperatures (>550 °C) are often needed to break C–H bonds, leading to deleterious side reactions in the alkane dehydrogenation process. Here we reduce the reaction temperature of n-butane dehydrogenation by fabricating a robust and regenerable Ir₁–Cu₁ dual-atom catalyst. The so-prepared system shows a turnover frequency of 2.45 s⁻¹ at 450 °C, which is 6.3 times higher than the single-atom Ir₁/ND@G catalyst, while, at he same time, achieving a high C₄ olefin selectivity of 98%. Importantly, key for the success of the Ir₁–Cu₁ dual-atom catalyst are the sterically favourable geometric configuration and the modulated electronic property, which can lower the reaction barrier for C–H activation, shift the rate-determining step and facilitate the desorption of the product. Thus, a remarkable activity can be achieved for n-butane dehydrogenation at relatively low temperature (≤450 °C).

Engineered polyketide synthases (PKSs) have great potential as biocatalysts. These unnatural enzymes are capable of synthesizing molecules that are either not amenable to biosynthesis or are extremely challenging to access chemically. PKSs can thus be a powerful platform to expand the chemical landscape beyond the limits of conventional metabolic engineering. Here we employ a retrobiosynthesis approach to design and construct PKSs to produce δ-valerolactam (VL) and three enantiopure α-substituted VL analogues that have no known biosynthetic route. We introduce the engineered PKSs and pathways for various malonyl-CoA derivatives into Pseudomonas putida and use proteomics, metabolomics and culture condition optimization to improve the production of our target compounds. These α-substituted VLs are polymerized into polyamides (nylon-5) or converted into their N-acryloyl derivatives. RAFT polymerization produces bio-derived polymers with potential biomedical applications. Overall, this interdisciplinary effort highlights the versatility and effectiveness of a PKS-based retrobiosynthesis approach in exploring and developing innovative biomaterials.

Propane dehydrogenation has been used industrially as a non-oil-based propylene production process, but it strongly depends on precious-metal catalysts such as supported Pt materials, which dominate most propane dehydrogenation processes currently used in industry. Catalysts with earth-abundant metals have been explored with a view to replacing Pt, but their performances remain inadequate. Here we report a cobaltosilicate zeolite catalyst, which has solely tetrahedral cobalt sites and none of the unstable cobalt species in the zeolite crystals that are characteristic of conventional cobaltosilicate materials. This catalyst exhibits properties that could be attractive for industrial application, including sufficient propylene productivity, high stability and facile regenerability. Moreover, this system outperforms the benchmark supported Pt–Sn catalysts under equivalent conditions.

Fe–N–C catalysts are the most promising alternative to Pt for the acidic oxygen reduction reaction (ORR), yet the electronic structure of their active centres remains elusive. Here we synthesize and characterize a conjugate-bridged iron phthalocyanine (FePc) dimer model catalyst with identical Fe sites and catalytic activity comparable to actual catalysts. A high-spin trivalent FeN₄ with an axial hydroxyl ligand, denoted as OH–Fe³⁺N₄ (S = 5/2), is identified as the active state. By contrast, monomer and non-conjugated dimer manifest the OH–Fe³⁺N₄ (S = 3/2) state with an excessive adsorption energy of ORR intermediates. Polymerized FePc is composed of 35% of the S = 5/2 state and 65% of the Fe²⁺N₄ (S = 0 or 1) state, showing a general weaker adsorption energy. Both overly strong and weak adsorption energy hinder the ORR. Theoretical calculations indicate that π–d interaction between Fe and the conjugated carbon plane dictates the spin state. This study will help to precisely design Fe-based ORR catalysts.

Chiral macrocycles play critical roles across medicinal chemistry and materials science, yet their catalytic asymmetric synthesis remains challenging. Existing methods predominantly rely on intramolecular cyclization of linear precursors and asymmetric resolution of racemic macrocycles, often requiring complex synthesis while offering limited structural diversity. Here, inspired by non-ribosomal cyclopeptide biosynthesis, we present a catalytic metallic dipole relay strategy for the construction of axially chiral macrolactones. This approach enables concise enantioselective synthesis through stepwise strain release in biaryl lactones and dynamic kinetic resolution mediated by π-allyl-Pd dipoles. The method demonstrates broad applicability to medium (up to 91% yield with 93% enantiomeric excess) and large (up to 93% yield with 99% enantiomeric excess and >19:1 diastereomeric ratio) ring systems under mild conditions. By establishing stereochemical control during both medium-ring formation and subsequent macrocyclization, this strategy overcomes traditional limitations in the generation of axial chirality while extending the methodology of transition-metal-catalysed asymmetric cyclization.

Nitric oxide (NO) emissions pose significant environmental challenges that demand sustainable remediation strategies. Here we report an electrochemical approach to convert NO into salt-free, concentrated nitric acid (HNO₃) using a carbon-based catalyst at near-ambient conditions. The system achieves >90% HNO₃ Faradaic efficiency (FE) at 100 mA cm⁻² with pure NO and retains >70% FE with dilute NO (0.5 vol%). Mechanistic studies identified nitrous acid as a critical intermediate, diverging from conventional thermocatalytic nitrogen dioxide pathways. By implementing a vapour-fed strategy in a membrane electrode assembly electrolyser, we directly synthesized 32 wt% HNO₃ from NO and deionized water, achieving 86% FE at 800 mA cm⁻² without electrolyte additives or downstream purification. This work establishes an electrochemical route to valorize NO emissions to high-purity HNO₃, advancing sustainable pollution mitigation and chemical manufacturing.

The linear scaling relationships between the adsorption energies of multiple intermediates constrain the maximum reaction activity of heterogeneous catalysis. Here we propose an intermediate spillover strategy to decouple the elementary electron-transfer steps in an electrochemical reaction by building a bi-component interface, thereby independently tuning the corresponding intermediate adsorption at an individual catalytic surface. Taking the electrocatalytic oxygen reduction reaction as an example, oxophilic sites are preferable for activating oxygen molecules, then the adsorbed OH* intermediates spontaneously migrate to the adjacent sites with a weaker oxygen binding energy, where OH* intermediates are further reduced and desorbed to complete the overall catalytic cycle. Consequently, the designed Pd/Ni(OH)₂ catalyst can remarkably elevate the half-wave potential of the oxygen reduction reaction to ~70 mV higher than that of the Pt/C catalyst, surmounting the theoretical overpotential limit of Pd. This design principle highlights an opportunity for utilizing intermediate spillover to break the ubiquitous scaling relationships in multi-step catalytic reactions.

Catalytic hydrogenation of carbonyl compounds is widely used in chemical manufacturing and biomass refining, but current thermocatalytic processes require elevated temperatures, high-pressure H₂ and expensive catalysts. Here we demonstrate an electroreduction of carbonyl compounds over Fe/Fe₂O₃ interfaces in Fe/Fe₂O₃ nanoarrays (Fe/Fe₂O₃ NAs), where Fe and Fe₂O₃ species synergistically accelerate the kinetics of acetone hydrogenation by promoting acetone adsorption and H* formation. With acetone as the probe molecule, an isopropanol partial current density of 1.6 A cm⁻² and ~100% selectivity are achieved in 1 M KOH aqueous solution. Even in a large-scale, two-electrode electrolyser, Fe/Fe₂O₃ NAs stably deliver an acetone conversion of >99%, an isopropanol selectivity of 100%, and an isopropanol production rate of 21.6 g g_cat⁻¹ h⁻¹ at 0.2 A cm⁻² over a 1,000-h operation. Moreover, Fe/Fe₂O₃ NAs were applied in the electrochemical hydrogenation of various carbonyl compounds to corresponding alcohols with high conversion rates and selectivities.

The electrochemical potential of a catalyst defines the free-energy landscape of catalysis in liquid media and is readily measured for catalysts supported on conductive materials or wired to external circuits. However, the potential is difficult to quantify for thermochemical catalysts supported on electrical insulators, thereby impeding a unifying understanding of the role of electrochemical polarization during thermochemical catalysis. Here we develop a methodology to quantify the electrochemical potential of metal catalysts supported on insulators by introducing low concentrations of redox-active molecules that establish wireless electrical connections between the catalyst and a sensing electrode. Using this approach in tandem with simultaneous rate measurements, we demonstrate distinct rate-potential scalings for oxidative dehydrogenation of formic acid on SiO₂-supported and Al₂O₃-supported versus TiO₂-supported Pt and find deactivation modes specific to SiO₂-supported Pt. These developments enable the comprehensive investigation of the role of electrochemical polarization in thermochemical catalysis and complement the existing toolkit for mechanistic investigation in catalysis.

The site-selective functionalization of C(sp²)–H bonds represents a powerful strategy for the synthesis of structurally diverse compounds with broad applicability. Here we report efficient regioselective catalytic methods for the formation of benzyltrimethylsilanes through ruthenium-catalysed C(sp²)–H silylmethylation. The developed protocols enable selective functionalization at both ortho and meta positions within arenes bearing N-based directing groups. The resulting silylmethyl compounds can undergo diverse transformations, including nucleophilic aromatic substitution, carbonyl addition, olefination and desilylation. Significantly, the regiodivergent installation of silylmethyl synthetic handles allows for the synthesis of the pharmaceutical losmapimod and could further be applied in direct late-stage functionalizations. Mechanistically, an essential role for biscyclometallated ruthenium(II) species has been found, with the formation of intermediate ruthenium(III) species indicated by paramagnetic NMR experiments. These synthetic inventions and mechanistic elucidations signify a transformative step within ruthenium-catalysed C(sp²)–H functionalization, enabling diverse syntheses and providing a framework for future development.