O-(La)-promoted hydrogen transfer enables low-loading Pd catalysts for selective acetylene hydrogenation

Abstract

The selective hydrogenation of acetylene using Pd-based catalysts is often limited by high precious metal usage and competitive adsorption between hydrogen and acetylene on active sites, which reduces catalytic efficiency. To address this, we developed a PdAg catalyst supported on La-doped Al₂O₃, introducing O-(La) sites that enhance hydrogen storage and transfer. In-situ Fourier Transform Infrared Spectroscopy (FTIR), temperature-programmed desorption (TPD), and mass spectrometry analyses revealed that the O-(La) sites enable efficient storage of dissociated hydrogen, which selectively reacts with acetylene, reducing competition on Pd sites. Density Functional Theory (DFT) calculations confirmed that the O-(La) sites reduce the energy barrier for hydrogen migration and enhance acetylene hydrogenation. This innovative approach reduces the Pd content by up to 30% while achieving superior catalytic performance, offering a cost-effective and scalable solution for industrial hydrogenation processes.