Center for Excellence in Regional Atmospheric Environment and Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Environ Sci Technol. 2022 Jul 5;56(13):9744-9750. doi: 10.1021/acs.est.2c02395. Epub 2022 Jun 15.
Thermal stability is crucial for the practical application of deNO catalysts. Vanadia-based catalysts are widely applied for the selective catalytic reduction of NO with NH (NH-SCR). Generally, hydrothermal aging at high temperatures induces the deactivation of deNO catalysts. However, in this work, a remarkable increase in low- and medium-temperature NH-SCR activity was observed for a VO/TiO catalyst after hydrothermal aging treatment, especially at 750 °C for 16 h. After the vanadia-based catalyst was hydrothermally treated at 750 °C, the specific surface area decreased and the surface VO density and surface V ratio increased significantly. Therefore, the aged catalyst presented more abundant polymeric vanadyl species than the fresh one. Furthermore, the redox capability was improved markedly after hydrothermal treatment due to the strong interaction of vanadia and titania, contributing to the NH-SCR reaction. 750 °C is the optimal temperature to activate the VO/TiO catalyst, improving the SCR performance significantly. This study provides an in-depth understanding of vanadia-based catalysts for practical applications.
热稳定性对于脱硝催化剂的实际应用至关重要。基于 V2O5 的催化剂被广泛应用于 NH3（NH-SCR）选择性催化还原 NO。通常，高温水热老化会导致脱硝催化剂失活。然而，在这项工作中，经过水热老化处理后，VO/TiO2 催化剂在低温和中温 NH-SCR 活性方面表现出显著的提高，尤其是在 750°C 下老化 16 小时后。在水热处理后，基于 V2O5 的催化剂的比表面积减小，表面 VO 密度和表面 V 比例显著增加。因此，老化催化剂表现出比新鲜催化剂更丰富的聚合钒氧物种。此外，由于 V2O5 和 TiO2 之间的强相互作用，水热处理后氧化还原能力显著提高，这有助于 NH-SCR 反应。750°C 是激活 VO/TiO2 催化剂的最佳温度，可以显著提高 SCR 性能。本研究为基于 V2O5 的催化剂的实际应用提供了更深入的了解。
