Zhang Chenhang, Dou Baojuan, Wei Xiaolin, Kang Running, Liang Wenjun, Bin Feng
Key Laboratory of Beijing on Regional Air Pollution Control, Beijing University of Technology, Beijing 100124, PR China; State Key Laboratory of High-Temperature Gas Dynamics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, PR China.
College of Marine and Environmental Sciences, Tianjin University of Science & Technology, Tianjin 300457, PR China.
J Hazard Mater. 2025 Sep 15;496:139226. doi: 10.1016/j.jhazmat.2025.139226. Epub 2025 Jul 11.
The utilization of carbon-free NH gas can be extended from low-concentration environmental applications to high-concentration energy applications. To achieve this, minimizing NO formation while maximizing energy release is essential. In this study, we investigated the catalytic performance of catalysts with different acid site characteristics, including a non-acidic catalyst, CuO-CeO supported on TiO providing only Lewis acid (LA) sites, and a catalyst with both Brønsted acid (BA) and LA sites at the same active sites. These catalysts were used to examine the synergistic effects of BA and LA sites in NH catalytic combustion. Results show that proton transfer at BA sites, where H protonates NH to form NH, stabilizes NH, reducing reactive NH intermediates and enhancing NO reduction efficiency by interacting with NO.In-situ impedance spectroscopy and diffuse reflectance infrared spectroscopy reveal that NH formed on BA sites migrates, interacting with reductive NO species to prevent nitrate decomposition and limit NH formation. The O isotope tracing of O species in NO reveals that NH promotes NO conversion to N via an internal selective catalytic reduction (i-SCR) mechanism, maintaining NO concentrations below 50 ppm at temperatures below 550°C. Based on this specially designed catalyst, the combination of advanced in-situ analytical techniques and isotopic tracing highlights a crucial pathway for NH-mediated NO reduction at acidic sites. The utilization of carbon-free NH gas can be extended from low-concentration environmental applications to high-concentration energy applications, requiring minimized NO formation alongside maximized energy release.
无碳氨气的应用可从低浓度环境应用扩展到高浓度能源应用。要实现这一点，最大限度地减少氮氧化物的形成同时最大化能量释放至关重要。在本研究中，我们研究了具有不同酸位点特性的催化剂的催化性能，包括非酸性催化剂、负载在二氧化钛上仅提供路易斯酸（LA）位点的氧化铜 - 氧化铈，以及在相同活性位点同时具有布朗斯特酸（BA）和LA位点的催化剂。这些催化剂用于研究BA和LA位点在氨催化燃烧中的协同作用。结果表明，在BA位点发生质子转移，其中H使氨质子化形成铵，使铵稳定，减少活性氨中间体，并通过与氮氧化物相互作用提高氮氧化物还原效率。原位阻抗谱和漫反射红外光谱表明，在BA位点形成的铵发生迁移，与还原性氮氧化物物种相互作用以防止硝酸盐分解并限制铵的形成。对氮氧化物中氧物种的氧同位素示踪表明，铵通过内部选择性催化还原（i-SCR）机制促进氮氧化物转化为氮气，在低于550°C的温度下将氮氧化物浓度保持在50 ppm以下。基于这种特殊设计的催化剂，先进的原位分析技术和同位素示踪相结合突出了酸性位点上铵介导的氮氧化物还原的关键途径。无碳氨气的应用可从低浓度环境应用扩展到高浓度能源应用，这需要在最大限度释放能量的同时尽量减少氮氧化物的形成。
