Synthesis gas to alcohols over noble metal promoted FeCu-LDH nano catalyst

Abstract

A highly dispersed FeCu/LDH-based catalyst precursor was prepared by co-precipitation method, and the catalysts promoted with Pd, Pt or Rh were then prepared using an equal-volume impregnation method to be used in syngas-to-alcohol reaction. These samples were characterized by XRD, Raman, FT-IR, In-situ DRIFT, XPS, SEM and N₂ adsorption desorption. The study reveals that the 2D nanosheet structure of the LDH precursor has a large surface area and evenly distributed active sites, leading to the superior catalyst performance. The promoted catalyst generated even higher catalytic activity and alcohol selectivity, notably reducing undesired methane and CO₂ by-products. Rh incorporation obviously enhanced the thermal stability of the catalyst, leading to the long-term retention of the LDH structure. Rich -OH groups offer surface basicity, thereby significantly enhancing its catalytic performance to lower the CO₂ selectivity to 1.34 % and methane to 1.67 % while achieving a remarkable alcohol selectivity of 95.1 %. In-situ DRIFT results reveal that Rh promotion helps balance the gaseous adsorption and bridge adsorption of CO for improved overall syngas-to-alcohols reaction results.