Manipulating the Coordination Structure of Biomass‐Derived Zinc Single‐Atom Sites to Boost Selective Catalytic Hydrogenation of Nitroarenes

ABSTRACT

Constructing highly efficient and stable non‐noble metal catalysts for selective hydrogenation of nitroarenes is a very appealing yet challenging task in the fields of materials science and catalysis. Herein, a series of N‐doped carbon‐anchored Zn single‐atom catalysts were prepared by pyrolyzing the biomass‐based composite precursors composed of chitosan, tannic acid, and ZnCl ₂ . The optimal sample of Zn‐Cl/NC‐3_900 displays superior catalytic activity with a turnover frequency of 4817 h ⁻¹ at 80°C, selectivity (∼99%), and recyclability (without any post‐treatment) for hydrogenation of p ‐chloronitrobenzene to p ‐chloroaniline with N ₂ H ₄ ·H ₂ O. Its catalytic performance is well kept even after HCl or KSCN treatments, revealing excellent chemical stability and anti‐poisoning capability. Additionally, a very high p ‐chloroaniline selectivity (∼98%) could be obtained under mild conditions (1.0 MPa, 100°C) when H ₂ is used as reductant. Characterization results and theory calculations demonstrate that introducing an appropriate amount of N/Cl species may finely modulate the local coordination environments of Zn single‐atoms. The resultant axially Cl‐coordinated ZnN ₂ sites (Zn‐N ₂ Cl) possess moderated adsorption/desorption capability and lower activation barriers, in line with the Sabatier principle, thereby significantly boosting the catalytic hydrogenation performance. This work provides a simple and effective approach for developing efficient hydrogenation catalysts through manipulating the coordination structure of metal single‐atom sites.