Longo Victor, De Pasquale Luana, Tavella Francesco, Barawi Mariam, Gomez-Mendoza Miguel, de la Peña O'Shea Víctor, Ampelli Claudio, Perathoner Siglinda, Centi Gabriele, Genovese Chiara
Department of Chemical, Biological, Pharmaceutical and Environmental Sciences and CASPE (INSTM), University of Messina, Viale F. Stagno D'Alcontres 31 98166 Messina Italy
Photoactivated Processes Unit, IMDEA Energy, Avda. Ramón de la Sagra, 3 Móstoles 28935 Madrid Spain.
EES Catal. 2024 Jul 3;2(5):1164-1175. doi: 10.1039/d4ey00112e. eCollection 2024 Sep 5.
The photocatalytic non-oxidative coupling of methane (NOCM) is a highly challenging and sustainable reaction to produce H and C hydrocarbons under ambient conditions using sunlight. However, there is a lack of knowledge, particularly on how to achieve high photocatalytic yield in continuous-flow reactors. To address this, we have developed a novel flow-through photocatalytic reactor for NOCM as an alternative to the conventionally used batch reactors. Me/TiO photocatalysts, where Me = Au, Ag and Pd, are developed, but only those based on Pd are active. Interestingly, the preparation method significantly impacts performance, going from inactive samples (prepared by wet impregnation) to highly active samples (prepared by strong electrostatic adsorption - SEA). These photocatalysts are deposited on a nanomembrane, and the loading effect, which determines productivity, selectivity, and stability, is also analysed. Transient absorption spectroscopy (TAS) analysis reveals the involvement of holes and photoelectrons after charge separation on Pd/TiO (SEA) and their interaction with methane in ethane formation, reaching a production rate of about 1000 μmol g h and a selectivity of almost 95% after 5 hours of reaction. Stability tests involving 24 h of continuous irradiation are performed, showing changes in productivity and selectivity to ethane, ethylene and CO. The effect of a mild oxidative treatment (80 °C) to extend the catalyst's lifetime is also reported.
甲烷的光催化非氧化偶联反应（NOCM）是一种极具挑战性且可持续的反应，即在环境条件下利用阳光生产氢气和碳氢化合物。然而，目前仍缺乏相关知识，特别是关于如何在连续流反应器中实现高光催化产率。为了解决这个问题，我们开发了一种用于NOCM的新型流通式光催化反应器，以替代传统使用的间歇式反应器。我们制备了Me/TiO光催化剂，其中Me = Au、Ag和Pd，但只有基于Pd的光催化剂具有活性。有趣的是，制备方法对性能有显著影响，从无活性的样品（通过湿浸渍法制备）到高活性的样品（通过强静电吸附 - SEA法制备）。这些光催化剂沉积在纳米膜上，还分析了决定生产率、选择性和稳定性的负载效应。瞬态吸收光谱（TAS）分析揭示了电荷分离后空穴和光电子在Pd/TiO（SEA）上的参与情况以及它们在乙烷形成过程中与甲烷的相互作用，反应5小时后达到约1000 μmol g⁻¹ h⁻¹的产率和约95%的选择性。进行了涉及24小时连续照射的稳定性测试，结果显示生产率以及对乙烷、乙烯和一氧化碳的选择性发生了变化。还报道了温和氧化处理（80°C）对延长催化剂寿命的影响。
