Efficient catalytic removal of COS and H2S over graphitized 2D micro-meso-macroporous carbons endowed with ample nitrogen sites synthesized via mechanochemical carbonization

• Published in: Green energy & environment Vol. 7; no. 5; pp. 983 - 995
• Main Authors: Kan, Xun, Zhang, Guanqing, Luo, Yingying, Liu, Fujian, Zheng, Yong, Xiao, Yihong, Cao, Yanning, Au, Chak-tong, Liang, Shijing, Jiang, Lilong
• Format: Journal Article
• Language: English
• Published: KeAi Communications Co., Ltd 01-10-2022
• Subjects: 2D micro-meso-macropores; COS hydrolysis; Graphitized porous carbons; H2S oxidation; Structural base nitrogen sites
• ISSN: 2468-0257; 2468-0257
• DOI: 10.1016/j.gee.2020.12.016

Developing a suitable catalyst for the elimination of highly toxic carbonyl sulfide (COS) and hydrogen sulfide (H2S) is of great significance in terms of industrial safety and environmental protection. We demonstrate here the facile synthesis of graphitized 2D micro-meso-macroporous carbons by one-step carbonization of a mixture of urea and glucose at 700–900 °C. The as-synthesized graphitized catalysts, designated as 2D-NHPC-x (x = urea/glucose mass ratio), are endowed with an ultra-high concentration (12.9–20.2 wt%) of stable and versatile nitrogen sites (e.g. pyrrole and pyridine) which are anchored on the surface via stable covalent bonding. As a result, the 2D-NHPC-x are active in catalytic hydrolysis of COS on pyrrolic N to H2S, and the H2S can be subsequently captured on pyridinic N and converted to elemental sulfur at ambient conditions over the same materials. Among the prepared catalysts, 2D-NHPC-x can catalytically hydrolysize 91% of COS to H2S at 30 °C, whereas the conversion ratio over the common catalysts g-C3N4 and Fe2O3 are below 6.0%. Furthermore, these catalysts also exhibit H2S conversion and sulfur selectivity of nearly 100% at 180 °C with long-time durability, which is higher than those of the most reported carbon-based catalysts. In contrast, the H2S capacities of activated carbon, ordered mesoporous carbons (OMC) and N-doped OMC are 3.9, 1.5 and 2.39 mmol g−1, respectively. Both the experimental and theoretical results are disclosed that 2D-NHPC-x are superior to the nitrogen-doped porous materials ever applied in simultaneous catalytic elimination of both COS and H2S.