High-density pyridine-FeN4 active sites for acetylene hydrochlorination

The high price of precious metal catalysts is an important factor restricting their industrial implementa-tion. Therefore, developing single-atom Fe-N4 catalysts with high site density is crucial. We precisely syn-thesize Fe-N-C microporous catalysts (Cs-Fe-600, 600 represent pyrolysis temperature is 600 & DEG;C) by exploiting the abundant pyridine-N confinement effect. The Fe content is up to 1.9 wt%. Cs-Fe-600 with dense pyridine-FeN4 sites was used as a catalyst in acetylene hydrochlorination reaction. It showed higher acetylene conversion compared to the carbon-nitrogen material without Fe addition. Characterization showed that the high Fe density was uniformly distributed on the carrier as stable pyridine-FeN4 active sites. And the result of characterization confirmed the strong adsorption ability of pyridine-FeN4 for acetylene, the primary active site in the reaction. The Cs-Fe-600 catalyst was deacti-vated by the agglomeration of Fe metal and the loss of pyridine-FeN4 active site. However, pyridine-FeN4 active sites and initial acetylene conversion recovered by high temperature treatment in ammonia gas. We successfully proposed a strategy for controlling Fe sites in specific nitrogen-coordination environment. & COPY; 2023 Elsevier Inc. All rights reserved.

Automated summary

The high price of precious metal catalysts hinders their industrial implementation. Therefore, it is crucial to develop single-atom Fe-N4 catalysts with high site density. We synthesized Fe-N-C microporous catalysts (Cs-Fe-600) using pyridine-N confinement effect, which showed higher acetylene conversion compared to carbon-nitrogen material without Fe addition. The Cs-Fe-600 catalyst deactivated due to agglomeration of Fe metal and loss of pyridine-FeN4 active site, but recovered through high temperature treatment in ammonia gas.