Hierarchically nanostructured bimetallic NiCo/MgxNiyO catalyst with enhanced activity for phenol hydrogenation

Abstract

Hierarchical hollow bimetallic NiCo/MgxNiyO catalysts were constructed by assembling NiMgCo layered double hydroxide (LDH) platelets on zeolitic imidazolate framework-67 (ZIF-67), followed by subsequent calcination and reduction. The three-level hierarchical structure of NiCo/MgxNiyO catalysts, including the hollow structure, nanolamellar structure and NiCo alloy particles, showed a significant enhancement on the catalytic activity of NiCo/MgxNiyO in the hydrogenation of phenol to cyclohexanol. The confined environment of the lamellar structure may strengthen the interaction between the active species and support, avoiding the agglomeration, sintering and leaching of the NiCo active species, thus facilitating the stability. The optimal catalyst NiCo/MgxNiyO(10) showed an excellent catalytic performance with 99.9 % conversion and 99.9 % selectivity for cyclohexanol, and featured with a highest TOF value of 588 h−1 compared with the reported Ni-based catalysts. Detailed characterizations have demonstrated that the combination of the hollow structure and the confined effect would benefit the catalytic performance. Moreover, this non-precious metal catalyst can be magnetically separated, and recycled for at least 6 times. This approach provides a valuable guidance for the design and preparation of the non-precious metal catalysts for industrial applications.