Selective Reduction of Nitroarenes via Noncontact Hydrogenation

Modulation of active site in CePO4/PtCo via multiple synergistic effects for enhanced nitroaromatic hydrogenation

The hydrogenation of nitroaromatics to aromatic amines is widely applied in the chemical, pharmaceutical, and agrochemical industries. However, the high cost of traditional precious metal-supported catalysts limits their industrial development. To address this, a PtCo alloy nanoparticle catalyst supported on CePO4 (CePO4/PtCo) was designed. The catalyst exhibits high activity and selectivity for the hydrogenation of nitroaromatics under 60 °C and 5 bar H2, achieving 100 % conversion of p-nitrophenol and 98.2 % selectivity to aromatic amines within 50 min. Catalytic mechanism studies indicate that the multi-level modulation of active sites is achieved through the synergistic interplay of dual mechanisms: electron transfer within PtCo alloys and metal-support interactions between PtCo and CePO4. This multiple synergy enables precise electronic tuning of Pt sites, enhancing the adsorption capacity for nitroaromatics and reducing the reaction energy barriers of potential-determination steps. Meanwhile, the functional support CePO4 adsorbs and activates the substrate, providing additional active sites for hydrogenation under hydrogen spillover. The multiple synergistic effects between the components of the catalyst revealed in this study provide new insights for the rational design of heterogeneous catalysts.

Solvent-Controlled and Highly Chemoselective Reduction of α,β-Unsaturated Ketones and Aldehydes

Herein, we establish two highly efficient reductions of α,β-unsaturated ketones and aldehydes via Raney nickel-catalyzed hydrogenation with distinct chemoselectivity, which is controlled by the solvent. This methodology demonstrates a brilliant result when reducing α,β-unsaturated ketones and aldehydes to ketones or alcohols. High isolated yields were obtained for a series of benzalacetone- and cinnamaldehyde-derived substrates without additional column chromatographic purification. The practicability of the methodology was demonstrated by reducing the natural products and synthesizing the approved drug.

Engineering S-Scheme Heterojunction via MOF-on-MOF for Photocatalytic Nitroarene Hydrogenation

Photocatalytic nitroarene reduction provides a promising strategy for the sustainable production of aniline. The construction of S-scheme heterostructures with a clear interfacial charge transfer mechanism is considered as an effective strategy to improve the photocatalytic performance of photocatalysts. The assembly of MOF-on-MOF might be used to construct S-scheme heterojunctions due to the rich structures, effective charge transport channels, and fast mass transfer of MOFs. Herein, 2D Pd-PPF-1 was coated on 3D Pd-PCN-222 through a presurface modification strategy, and the prepared Pd-PPF-1/Pd-PCN-222 with an S-scheme heterojunction displayed the morphology of a 2D nanoflower winding around a 3D rod. As for photocatalytic nitroarene hydrogenation, the as-obtained Pd-PPF-1/Pd-PCN-222 catalyst exhibited much higher photocatalytic performance than Pd-PPF-1, Pd-PCN-222, or a physical mixture of Pd-PPF-1 and Pd-PCN-222. The high catalytic performance of Pd-PPF-1/Pd-PCN-222 might be attributed to the formation of the S-scheme heterojunction, which not only retained the redox capability of the parent MOFs but also separated photogenerated carriers. This work presents a constructive route for designing 2D-on-3D MOF S-scheme heterojunction with controllable morphology and high photocatalytic ability.