1. Active nitrogen sites on nitrogen doped carbon for highly efficient associative ammonia decomposition
- Author
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Dongpei Ye, Kwan Chee Leung, Wentian Niu, Mengqi Duan, Jiasi Li, Ping-Luen Ho, Dorottya Szalay, Tai-Sing Wu, Yun-Liang Soo, Simson Wu, and Shik Chi Edman Tsang
- Subjects
Catalysis ,Chemistry ,Materials chemistry ,Materials science ,Science - Abstract
Summary: Nitrogen doped carbon materials have been studied as catalyst support for ammonia decomposition. There are 4 different types of nitrogen environments (graphitic, pyrrolic, pyridinic and nitrogen oxide) on the amorphous support identified. In this paper, we report a 5%Ru on MgCO3 pre-treated nitrogen doped carbon catalyst with high content of edge nitrogen-containing sites which displays an ammonia conversion rate of over 90% at 500°C and WHSV = 30,000 mL gcat−1 h−1. It also gives an impressive hydrogen production rate of 31.3 mmol/(min gcat) with low apparent activation energy of 43 kJ mol−1. Fundamental studies indicate that the distinct average Ru-N4 coordination site on edge regions is responsible for such high catalytic activity. Ammonia is stepwise decomposed via a Ru-N(H)-N(H)-Ru intermediate. This associative mechanism circumvents the direct cleavage of energetic surface nitrogen from metal to form N2 hence lowering the activation barrier for the decomposition over this catalyst.
- Published
- 2024
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