Zn stabilized Pd clusters with enhanced covalent metal-support interaction the formation of Pd-Zn bonds to promote catalytic thermal stability

• Published in: Nanoscale Vol. 12; no. 27; pp. 14825 - 1483
• Main Authors: Jing, Kai-Qiang, Fu, Yu-Qing, Wang, Zhi-Qiao, Chen, Zhe-Ning, Tan, Hong-Zi, Sun, Jing, Xu, Zhong-Ning, Guo, Guo-Cong
• Format: Journal Article
• Language: English
• Published: 16.07.2020
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/d0nr02987d

Pd-Based heterogeneous catalysts have been demonstrated to be efficient in numerous heterogeneous reactions. However, the effect of the support resulting in covalent metal-support interaction (CMSI) has not been researched sufficiently. In this work, a Lewis base is modulated over MgAl-LDH to investigate the support effects and it is further loaded with Pd clusters to research the metal-support interactions. MgAl-LDH with ultra-low Pd loading (0.0779%) shows CO conversion (55.0%) and dimethyl oxalate (DMO) selectivity (93.7%) for CO oxidative coupling to DMO, which was gradually deactivated after evaluation for 20 h. To promote the stability of Pd/MgAl-LDH, Zn 2+ ions were introduced into the MgAl-LDH support to strengthen the CMSI by forming Pd-Zn bonds, which further increased the adsorption energy of the Pd clusters on ZnMgAl-LDH, and this was verified by X-ray absorption fine structure (XAFS) measurements and density functional theory (DFT) calculations. The stability of the Pd/ZnMgAl-LDH catalyst could be maintained for at least 100 h. This work highlights that covalent metal-support interactions can be strengthened by forming new metal-metal bonds, which could be extended to other systems for the stabilization of noble metals over supports. Zn 2+ -Modified MgAl-LDH with ultra-low Pd cluster loading was synthesized. The higher adsorption energy and strong covalent metal-support interaction via forming Pd-Zn bonds over Pd/ZnMgAl-LDH account for the robust catalytic performance.