A bimetallic strategy to tailoring the surface formation energy and d-band center of Ni-based catalyst for efficient and stable catalytic hydrogenation of dioctyl phthalate

Abstract

Hydrogenation of dioctyl phthalate (DOP) is an effective strategy to synthesize cyclohexane-1,2-dioctyl phthalate (CDP), an environmentally friendly plasticizer. Many catalysts have already been developed to achieve the hydrogenation of DOP. However, due to the stability of their aromatic rings, the high costs of noble metal catalysts, and the harsh reaction conditions, the fabrication of non-noble metal catalysts with high activity and stability is still challenging. In this work, we report a bimetallic strategy built on the confinement effect to prepare a Ni2.5Cu0.5Al1 bimetallic catalyst using Ni-Cu hydrotalcite as the precursor. Results show that DOP conversion and selectivity of CDP could both reach 99%; also, the suggested bimetallic catalyst exhibits excellent stability under harsh reaction conditions, e.g., the catalyst can be recycled up to 9 times with no change in conversion and selectivity. Certain characterizations and theoretical calculations show that introduction of an appropriate amount of Cu can reduce the surface formation energy and d-band center, which can simultaneously improve the activity and stability of the Ni-based catalysts. Therefore, the proposed Ni-Cu bimetallic catalyst is an attractive option for the synthesis of environmentally friendly plasticizers by DOP hydrogenation.