Synergistic Regulation of Geometric and Electronic Structures in Embedded Ni Catalysts via Halogen-Doped Carbon Dots for Efficient Selective Hydrogenation

The breakthrough in the performance of carbon-supported non-noble-metal catalysts lies in the synergistic optimization of geometric size and electronic structure; however, the high surface energy of metals tends to induce agglomeration, and the weak interfacial electronic coupling between metals and carbon makes precise regulation of electronic structure challenging. Herein, an incomplete encapsulation of Ni nanoparticles (Ni NPs) -embedded structure is achieved after the self-assembly of Ni species and halogen-doped carbon dots and the subsequent pyrolysis process. The F atoms, endowed with the strong electron-withdrawing capability, abstract electrons from the outer shell of Ni species, which not only accelerates interfacial electron transfer of the catalyst, thus modulating the d-band center of Ni, but also suppresses the formation of Ni−Ni bonds, thereby weakening the intrinsic driving force for metal agglomeration. Among them, the catalyst Ni@FCDs doped with F atoms exhibits the highest adsorption and dissociation ability for reactant molecules, demonstrated by the extended X-ray absorption fine-structure and density functional theory calculations, and the smallest metal particle size (5.54 nm), thus expressing high catalytic hydrogenation activity. Furthermore, the embedded structure effectively inhibits the sintering of Ni NPs during the reaction, and the metal particle size remains stable after 9 cycles of reaction. The synergistic optimization of geometric size and electronic structure of the metal species induced by the “halogen doping dual regulation” strategy provides an innovative approach for the design of high-performance nickel-based catalysts and deepens the understanding of the structure−activity relationship in carbon-supported metal catalysts.