Preparation-Dependent Lanthanum Promotion of Ni/MCM-41 for Mild Hydrogenation of Dioctyl Phthalate

The hydrogenation of dioctyl phthalate (DOP) to dioctyl 1,2-cyclohexanedicarboxylate represents an effective pathway for the production of environmentally friendly plasticizers. However, due to the intrinsic stability of the aromatic ring, the development of efficient and stable non-noble metal catalysts remains a key challenge. In this work, an efficient and stable La-modified MCM-41-supported Ni catalyst (Ni/La-M) was developed. The effects of different La introduction methods on the structural and catalytic properties of the catalyst were systematically investigated. The Ni/La-M catalyst, prepared via a two-step hydrothermal method, achieved 99% DOP conversion under mild conditions (140 °C, 2 MPa H 2 , 1 h) and retained over 90% activity after nine cycles. Characterization results revealed that La incorporation significantly enhanced the interaction between Ni and the support, effectively suppressed Ni particle sintering, and increased the fraction of exposed active sites. Compared with other La-introduction methods, the “La-first, Ni-second” strategy exhibited superior activity retention and cycling stability. This approach provides a new design strategy concept for constructing high-performance non-noble metal catalysts in a controllable manner. Graphical La was introduced during MCM-41 synthesis to build a La-modified support, enhancing Ni–support interaction, dispersing Ni species, and increasing catalyst acidity. This strategy improves catalytic activity for dioctyl phthalate hydrogenation to dioctyl 1,2-cyclohexanedicarboxylate and suppresses Ni sintering and leaching, providing mechanistic insight for designing stable green hydrogenation catalysts.