Iron-Based Catalysts with Oxygen Vacancies Obtained by Facile Pyrolysis for Selective Hydrogenation of Nitrobenzene

Sabatier Principle Driving Interface Defect Engineering on 3D Graphene-Like Encapsulated Cobalt Structure for Hydrogenation Reaction

Establishing structural defects is a perspective way to increase the catalytic hydrogenation reaction. Toward Sabatier optimization for hydrogenation reaction with defect density offers guidance for designing optimal catalysts with the highest performance. A controllable synthesis strategy is reported for Co@NC-x catalyst induced by defect density. A series of N-doped carbon-based defective Co@NC-x catalysts with different defect densities ranging from 1.5 × 1011 to 1.9 × 1011 cm-2 via high-temperature sublimation strategy is obtained. The results show that the volcano curves are observed between defect density and catalytic hydrogenation performance with a summit at a moderate defect density of 1.7 × 1011 cm-2, matched well with Sabatier phenomenon. Remarkably, the defect density on the graphene-like shell serves as descriptor to the adsorbate state and consequently the catalytic activity. However, to the best of knowledge, the Sabatier phenomenon in hydrogenation reactions at the defect scale in 3D graphene-like encapsulated metal (3D-GEM) catalysts has not been reported. This work highlights the meaning of defect-density effect on catalytic hydrogenation reaction, supplying meaningful guidance for the rational design of more efficient and durable defective 3D-GEM catalyst.

Aromatic Ethers Induced Electronic Structure Reconstruction on Encapsulated Nickel Catalysts for High-Performance Catalytic Hydrogenation

Carbon-encapsulated metal (CEM) catalysts effectively address supported metal catalyst instability by protecting the active metal with a shell. However, mass transfer limitations lead to reduced activity for catalytic hydrogenation reaction over most CEM catalysts. Herein, we introduce a dopant strategy aimed at incorporating nickel metal within graphene-like shells (GLS) featuring oxygen-containing functional groups (OFGs). The core of this strategy involves precise control of GLS modification and the demonstrated pivotal influence of aromatic ether linkages (═C-O-C) in GLS for significant enhancement of catalytic performance. The introduction of ═C-O-C into GLS with stability was beneficial to improve the work function of the catalyst and promoted electron transmission from Ni metal core to GLS, further elevating the catalytic activity, based on the Mott-Schottky effect. In addition, the experimental characterization and density functional theory (DFT) calculations showcased that the ═C-O-C reconstructed the electronic state of GLS, imparting it highly specific for the adsorption of hydrogen and para-chloronitrobenzene (p-CNB) to obtain para-chloroaniline (p-CAN) with high selectivity. This work manifested a feasible direction for the precise modulation and design of the OFGs in CEM catalysts to achieve highly efficient catalytic hydrogenation.