Decoupling Active Sites Enables Low-Temperature Semihydrogenation of Acetylene
Zhengwen Li, Jiajun Zhang, Jiaming Tian, Kai Feng, Yuxin Chen, Xiao Li, Zhihe Zhang, Shuairen Qian, Bin Yang, Dong Su, Kai Luo, Binhang Yan
Abstract
Achieving high ethylene selectivity while preserving high reactivity for semihydrogenation of acetylene over Pd-based catalysts is still challenging. Here, we propose a structure of encapsulated Pd nanoparticles to enhance catalytic performance via a low-dose doping-segregation strategy using Pd-doped SrTiO 3 as a precursor. The encapsulated Pd nanoclusters are revealed to be protected by a thin TiO x shell to prevent contact with acetylene/ethylene. However, hydrogen can still be efficiently activated on the encapsulated Pd sites and react with the adsorbed acetylene on surface Ti 3+ sites via hydrogen spillover. By taking advantage of weaker ethylene adsorption on partially reduced oxide TiO x, this catalyst shows an enhanced performance of 98% conversion and 92% selectivity with a specific activity of 5552 mol C2H2 ·mol Pd –1 ·h –1 at 100 °C, significantly surpassing most Pd-based catalysts. This strategy decouples active sites for the activation of different reactants, providing a thought for the development of highly active and selective hydrogenation catalysts.