Qingping Ke

The development of noble‐metal‐free heterogeneous catalysts for room‐temperature aerobic ammoxidation of alcohols to nitriles represents an enduring challenge, primarily hampered by unselective lattice‐oxygen over‐oxidation via the classical Mars–van Krevelen (MvK) pathway and strong site‐blocking effects. Herein, we report a dual‐anion (C/N) doped MnO _x (C/N–MnO _x ) synthesized via a green, solvent‐free crystallization strategy, which exhibits excellent catalytic performance (95.3% benzyl alcohol conversion, >99% benzonitrile selectivity) and broad substrate versatility (35 diverse alcohol substrates) under ambient conditions (25°C, 1 atm O ₂ ) without external energy inputs. Structural analyses and theoretical calculations demonstrate that N‐doping introduces medium‐strong Lewis acidic Mn–N sites to capture NH ₃ , while C‐doping generates localized oxygen vacancies for O ₂ activation. Crucially, kinetic isotope effect experiments and density functional theory (DFT) calculations prove that this anion dopant‐programmed relay catalysis successfully bypasses the MvK pathway, fundamentally shifting the rate‐determining step from initial alcohol dehydrogenation to the homolytic α –C–H bond scission of the aldimine intermediate. This work presents a paradigm shift in designing multifunctional non‐precious catalysts for ambient‐condition green organic transformations.

The development of noble‐metal‐free heterogeneous catalysts for room‐temperature aerobic ammoxidation of alcohols to nitriles represents an enduring challenge, primarily hampered by unselective lattice‐oxygen over‐oxidation via the classical Mars–van Krevelen (MvK) pathway and strong site‐blocking effects. Herein, we report a dual‐anion (C/N) doped MnO _x (C/N–MnO _x ) synthesized via a green, solvent‐free crystallization strategy, which exhibits excellent catalytic performance (95.3% benzyl alcohol conversion, >99% benzonitrile selectivity) and broad substrate versatility (35 diverse alcohol substrates) under ambient conditions (25°C, 1 atm O ₂ ) without external energy inputs. Structural analyses and theoretical calculations demonstrate that N‐doping introduces medium‐strong Lewis acidic Mn–N sites to capture NH ₃ , while C‐doping generates localized oxygen vacancies for O ₂ activation. Crucially, kinetic isotope effect experiments and density functional theory (DFT) calculations prove that this anion dopant‐programmed relay catalysis successfully bypasses the MvK pathway, fundamentally shifting the rate‐determining step from initial alcohol dehydrogenation to the homolytic α –C–H bond scission of the aldimine intermediate. This work presents a paradigm shift in designing multifunctional non‐precious catalysts for ambient‐condition green organic transformations.

The selective oxidation of cyclohexene to high-value cyclohex-2-enone using singlet oxygen holds significant importance in chemical production. However, conventional methods for generating singlet oxygen are often constrained by harsh conditions, typically requiring high-energy input. This study develops a new methodology that leverages the Pickering emulsion droplet interfaces to facilitate the generation of singlet oxygen for the efficient oxidation of cyclohexene. First, an amphiphilic catalyst SiO₂/CN_x was synthesized by growing hydrophobic nitrogen-doped carbon on the surface of hydrophilic sheet-like silica through a combined surface-polymerization and carbonization process. Such amphiphilic catalyst can then self-assemble at the interfaces of the oil phase (cyclohexene in ethyl acetate) and water phase (tert-butyl hydroperoxide aqueous solution), thereby stabilizing a water-in-oil Pickering emulsion. The graphitic nitrogen sites on the nitrogen-doped carbon promote the cleavage of tert-butyl hydroperoxide to form superoxide radicals, while the pyridinic nitrogen sites can adsorb and enrich the resulting radicals. In addition, the unique proton-rich microenvironment at the Pickering emulsion droplet interfaces promotes the disproportionation of adsorbed superoxide radicals, generating the desired singlet oxygen for the selective oxidation of cyclohexene. As a result, this Pickering emulsion system achieved a cyclohexene conversion of >99.0% with a 95.0% selectivity toward cyclohex-2-enone, significantly outperforming the results reported in prior studies. This strategy of harnessing the Pickering emulsion droplet interfaces to regulate the generation of highly reactive singlet oxygen opens up a promising route for the efficient synthesis of oxygenated fine chemicals.

Localized surface plasmon resonance (LSPR) opens a new avenue for solar-driven organic synthesis. In this work, we synthesize oxygen-vacancy-rich metallic LaSrCoMnO₆ nanoparticles (LSCMn-N) with pronounced LSPR in the visible region. Unlike their microsized counterparts (LSCMn-M), LSCMn-N exhibits a metallic band structure, with enhanced visible light absorption (peaking at 740 nm) and photocurrent density. Under visible light irradiation (λ = 740 nm) and a mild temperature of 70 °C, identified Mn and Co reaction sites promote LSCMn-N to achieve superior photocatalytic styrene epoxidation performance with 99.9% styrene conversion and 91.3% styrene oxide selectivity within 1.5 h, outperforming LSCMn-M by 5.7-fold. Mechanistic studies reveal that the LSPR-induced electric field promotes the generation of carbon-centered radicals via activating styrene by photogenerated holes, while the photogenerated electrons facilitate O₂ reduction to reactive oxygen species. This work highlights the potential of applying plasmonic double perovskites for driving highly efficient and selective solar-powered organic transformations, paving the way for sustainable chemical synthesis.

The predominant product of CO electroreduction (COER) is often acetate, with the Faradaic efficiency (FE) for ethanol usually falling below 50%. Herein, we propose a unique strategy to enhance product selectivity in COER, shifting it from acetate predominance toward ethanol generation via alloying atomic manganese (Mn) atoms with a face-centered cubic (FCC) copper (Cu) catalyst. By optimizing the atomic ratio of Mn to Cu, we observe an impressive enhancement of 8.8-fold for the ethanol-to-acetate FE ratio in the optimal Mn₃Cu₉₇ alloy compared to unalloyed FCC-phase Cu. Mn₃Cu₉₇ demonstrates a remarkable ethanol FE of nearly 70% at a high current density of 600 mA cm^-2 in a membrane electrode assembly electrolyzer. Further theoretical analysis reveals that atomically dispersed Mn atoms generate synergistic active sites and modulate the adsorption strength of critical intermediates relevant to ethanol synthesis, thereby facilitating the transition from the acetate pathway to the ethanol pathway.

Heterogeneously catalyzed liquid oxidation of olefins with O₂ provides an alternative way for synthesizing high-value added chemicals. Herein, we report a straightforward urea-redox and sol-gel process for synthesizing LaCo_xCu_1−xO₃ for aerobic photo-oxidation of cyclohexene. Our research highlights a marked increase in the proportions of Co²⁺ and Cu⁺ species in a low chemical state, as well as enhanced visible light absorption through this method. Mechanistic investigations suggest that the catalytic process, particularly with LaCo_0.7Cu_0.3O₃, involves a radical pathway mediated by reactive oxygen species. The presence of Cu⁺/Co²⁺ species and surface oxygen vacancies is proposed to boost O₂ adsorption and activation on the catalyst, facilitating the formation of 2-cyclohexene-1-hydroperoxides. Furthermore, Cu²⁺/Co³⁺ species are thought to aid in generating cyclohexene-derived radical species. The efficient aerobic oxidation of cyclohexene on LaCo_0.7Cu_0.3O₃ catalyst relies on the formation of reactive oxygen species and carbon radicals, facilitated by its strong visible light illumination. It achieves a cyclohexene conversion of 89.4% and selectivity to cyclohex-2-ene-1-one of 72.2%, along with stable recyclability after six reuses. The creation of nano-structured LaCo_xCu_1−xO₃ through the urea-redox and sol-gel process offers a promising avenue for the development of highly efficient catalysts for the aerobic photo-oxidation of cyclohexene to cyclohex-2-ene-1-one in the future.