Vacancy-directed Pt-N3Cl1 coordination engineering via flash joule heating for chemoselective nitroarene hydrogenation

The catalytic hydrogenation of nitroarenes to aromatic amines constitutes a pivotal transformation in fine chemical synthesis, yet existing catalysts face inherent trade-offs between activity, chemoselectivity, and structural stability. In this work, we demonstrate a vacancy-directed strategy enabled by flash Joule heating to engineer Pt single-atom catalysts with tailored Pt-N 3 Cl 1 coordination on nitrogen-doped activated carbon (Pt-NAC-J). The instantaneous thermal shock (1000 °C, 1 s) generates abundant vacancy-rich defects that enable ultra-dispersed Pt anchoring and reconfigure the Pt coordination from Pt-N 4 Cl 1 to asymmetric Pt-N 3 Cl 1 . Theoretical calculations reveal that the vacancy-induced charge redistribution at Pt-N 3 Cl 1 sites synergistically facilitates the adsorption of the -NO 2 group and the heterolytic dissociation of H 2 , thereby significantly enhancing the selective hydrogenation of nitroarenes. Compared to the conventional high-temperature pyrolyzed Pt-NAC-P catalyst, Pt-NAC-J exhibits prominent catalytic efficiency under mild conditions (40 °C, 0.5 MPa H 2 ) while preserving sensitive functional groups with >99 % selectivity. Remarkably, the catalyst maintains >99 % selectivity at elevated temperatures up to 100 °C and 100 % activity retention over 8 reaction cycles, showcasing unprecedented chemoselectivity and stability of the vacancy-stabilized Pt sites. The universality of this methodology is further evidenced through extension to a non-noble Co-NAC-J catalyst, which surpasses most reported non-precious metal systems in catalytic performance. This work opens a new avenue for vacancy-mediated coordination engineering in carbon-supported single-atom catalysts for industrial selective hydrogenation processes.