A green and scalable strategy has been developed for the synthesis of lignin-derived Zn single atom/N-codoped porous carbon (LCN@Zn-SAC) containing similar ZnN_x sites with carbonic anhydrases. This catalyst exhibits superior activity on the α-alkylation of ketones with alcohols via borrowing hydrogen strategy (TON up to 15 h⁻¹) than most of previously reported works. The dehydrogenation of benzyl alcohol is the rate-determining step based on kinetic experiment results. According to experimental and theoretical calculation results, Zn electron density is inversely proportional to reaction energy barriers, because Zn sites with less positive charge (ZnN₄ and ZnN₃C) in Zn-SACs display better borrowing hydrogen ability than other Zn sites. Furthermore, this catalyst can be recycled by simple centrifugation, which can be reused at least 8 runs with no obvious lose in activity. To the best of our knowledge, this is the first example of non-noble metal-SAC-catalyzed α-alkylation via borrowing hydrogen strategy.

A facile, gram-scale and sustainable approach has been established for the synthesis of single-atomic-site iron on N-doped carbon (Fe_SA@NC-20A) via the pyrolysis of aniline modified FeZn-ZIFs, in which the synthesis of zeolitic imidazolate frameworks (ZIFs) can be accomplished in water at room temperature, and no acid etching is required. The as-synthesized catalyst exhibits better performance on the chemoselective hydrogenation of nitroarenes with a broad substrate scope (turnover frequency (TOF) up to 1, 727 h^-1, 23 examples) than most of previously reported works. Based on high-angle annular dark field scanning transmission microscopy (HAADF-STEM) images in combination with X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), electron spin resonance (ESR), and Mössbauer spectroscopy, Fe is dispersed as single atoms via forming FeN_x (x = 4–6). This work not only determines the active sites of Fe_SA@NC-20A for hydrogenation (FeN₄), but also proposes tentative pathways for both N–H activation of hydrazine and the reduction of nitroarene on FeN₄ site, both of which are the key steps for the hydrogenation of nitroarenes. In addition, this catalyst shows excellent stability, and no significant activity degradation is observed when recycling for 10 times or restoring in air for 2 months.