School of Chemistry , Sichuan University , Chengdu 610000 , China.
Jiangsu Key Laboratory of Vehicle Emissions Control , Nanjing 210023 , China.
ACS Appl Mater Interfaces. 2019 Feb 6;11(5):4900-4907. doi: 10.1021/acsami.8b15688. Epub 2019 Jan 28.
Sulfur poisoning has long been recognized as a bottleneck for the development of long-lived NH-selective catalytic reduction (SCR) catalysts. Ammonium bisulfate (ABS) deposition on active sites is the major cause of sulfur poisoning at low temperatures, and activating ABS decomposition is regarded as the ultimate way to alleviate sulfur poisoning. In the present study, we reported an interesting finding that ABS decomposition can be simply tailored via adjusting the pore size of the material it deposited. We initiated this study from the preparation of mesoporous silica SBA-15 with uniform one-dimensional pore structure but different pore sizes, followed by ABS loading to investigate the effect. The results showed that ABS decomposition proceeded more easily on SBA-15 with larger pores, and the decomposition temperature declined as large as 40 °C with increasing pore size of SBA-15 from 4.8 to 11.8 nm. To further ascertain the real effect in NH-SCR reaction, the FeO/SBA-15 probe catalyst was prepared. It was found that the catalyst with larger mesopores exhibited much improved sulfur resistance, and quantitative analysis results obtained from Fourier transform infrared and ion chromatograph further proved that the deposited sulfates were greatly alleviated. The result of the present study demonstrates for the first time the vital role of pore size engineering in ABS decomposition and may open up new opportunities for designing NH-SCR catalysts with excellent sulfur resistance.
硫中毒长期以来一直被认为是长寿命 NH 选择性催化还原（SCR）催化剂发展的瓶颈。活性位上的硫酸氢铵（ABS）沉积是低温下硫中毒的主要原因，而激活 ABS 分解被认为是缓解硫中毒的最终途径。在本研究中，我们报告了一个有趣的发现，即通过调整沉积材料的孔径可以简单地调节 ABS 的分解。我们从具有均匀一维孔结构但不同孔径的介孔硅 SBA-15 的制备开始，然后进行 ABS 负载以研究其效果。结果表明，在具有较大孔的 SBA-15 上 ABS 分解更容易进行，并且随着 SBA-15 的孔径从 4.8nm 增加到 11.8nm，分解温度下降了高达 40°C。为了进一步确定在 NH-SCR 反应中的实际效果，制备了 FeO/SBA-15 探针催化剂。结果发现，具有较大介孔的催化剂表现出更好的抗硫性，并且从傅里叶变换红外和离子色谱获得的定量分析结果进一步证明了沉积的硫酸盐得到了极大的缓解。本研究的结果首次证明了孔径工程在 ABS 分解中的重要作用，并为设计具有优异抗硫性的 NH-SCR 催化剂开辟了新的机会。
