Enhanced activity of Ru-based catalysts for ammonia decomposition through nitrogen doping of hierarchical porous carbon carriers

Abstract

Activated carbon (AC) materials, renowned for their high specific surface area, excellent conductivity, and customizable functional groups, are widely employed as catalyst carriers. However, enhancing the activity of Ru-based catalysts supported on AC (Ru/AC) for ammonia decomposition remains a challenge. In this study, commercial AC was utilized as a substrate, with glucose and urea employed as modifiers. Specifically, the surface of the AC was modified via a hydrothermal pyrolysis method, resulting in the successful post-treatment in situ co-doping of nitrogen (AC-GN). Experimental results revealed that Ru/AC-GN exhibited a hydrogen production rate 46% higher than that of Ru/AC at 475 °C, indicating improved activity and stability. The characterization of AC-GN demonstrated that nitrogen doping primarily occurred on the external surface and macropores of the AC, increasing the nitrogen content in the carrier, particularly pyrrolic nitrogen content, while preserving the original structural and morphological integrity of the AC. The enhanced dispersion of Ru, combined with the improved electronic transmission capabilities and strengthened interactions between the metal and the modified carrier, were identified as pivotal factors contributing to the enhanced low-temperature efficacy of Ru/AC-GN. This paper presents a novel direction for the large-scale preparation of efficient catalysts for ammonia decomposition.