Bo Zheng, Yang Shiling, Kong Jing, Zhu Jinhui, Wang Yaolin, Yang Huachao, Li Xiaodong, Yan Jianhua, Cen Kefa, Tu Xin
State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, College of Energy Engineering, Zhejiang University, Hangzhou, Zhejiang Province 310027, China.
Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool L69 3GJ, U.K.
ACS Catal. 2020 Apr 3;10(7):4420-4432. doi: 10.1021/acscatal.9b04844. Epub 2020 Mar 25.
In this work, we propose a hybrid and unique process combining solar irradiation and post-plasma catalysis (PPC) for the effective oxidation of toluene over a highly active and stable MnO/GFF (bifunctional graphene fin foam) catalyst. The bifunctional GFF, serving as both the catalyst support and light absorber, is decorated with MnO nanofins, forming a hierarchical fin-on-fin structure. The results show that the MnO/GFF catalyst can effectively capture and convert renewable solar energy into heat (absorption of >95%), leading to a temperature rise (55.6 °C) of the catalyst bed under solar irradiation (1 sun, light intensity 1000 W m). The catalyst weight (9.8 mg) used in this work was significantly lower (10-100 times lower) than that used in previous studies (usually 100-1000 mg). Introducing solar energy into the typical PPC process via solar thermal conversion significantly enhances the conversion of toluene and CO selectivity by 36-63%, reaching ∼93% for toluene conversion and ∼83% for CO selectivity at a specific input energy of ∼350 J L, thus remarkably reducing the energy consumption of the plasma-catalytic gas cleaning process. The energy efficiency for toluene conversion in the solar-enhanced post-plasma catalytic (SEPPC) process reaches up to 12.7 g kWh, ∼57% higher than that using the PPC process without solar irradiation (8.1 g kWh), whereas the energy consumption of the SEPPC process is reduced by 35-52%. Moreover, the MnO/GFF catalyst exhibits an excellent self-cleaning capability induced by solar irradiation, demonstrating a superior long-term catalytic stability of 72 h at 1 sun, significantly better than that reported in previous works. The prominent synergistic effect of solar irradiation and PPC with a synergistic capacity of ∼42% can be mainly attributed to the solar-induced thermal effect on the catalyst bed, boosting ozone decomposition (an almost triple enhancement from ∼0.18 g g h for PPC to ∼0.52 g g h for SEPPC) to generate more oxidative species (e.g., O radicals) and enhancing the catalytic oxidation on the catalyst surfaces, as well as the self-cleaning capacity of the catalyst at elevated temperatures driven by solar irradiation. This work opens a rational route to use abundant, renewable solar power to achieve high-performance and energy-efficient removal of volatile organic compounds.
在本工作中，我们提出了一种将太阳能辐照与等离子体后催化（PPC）相结合的混合且独特的工艺，用于在高活性和稳定的MnO/GFF（双功能石墨烯翅片泡沫）催化剂上有效氧化甲苯。双功能GFF既作为催化剂载体又作为光吸收体，表面装饰有MnO纳米翅片，形成分级的翅上翅结构。结果表明，MnO/GFF催化剂能够有效地捕获可再生太阳能并将其转化为热量（吸收率>95%），在太阳辐照（1个太阳，光强1000 W m）下导致催化剂床层温度升高（55.6°C）。本工作中使用的催化剂重量（9.8 mg）显著低于先前研究中使用的重量（通常为100 - 1000 mg，低10 - 100倍）。通过太阳能热转换将太阳能引入典型的PPC工艺中，显著提高了甲苯的转化率和CO选择性，在特定输入能量约为350 J L时，甲苯转化率达到约93%，CO选择性达到约83%，从而显著降低了等离子体催化气体净化过程的能耗。太阳能增强后等离子体催化（SEPPC）过程中甲苯转化的能量效率高达12.7 g/kWh，比无太阳辐照的PPC过程（8.1 g/kWh）高约57%，而SEPPC过程的能耗降低了35 - 52%。此外，MnO/GFF催化剂在太阳辐照下表现出优异的自清洁能力，在1个太阳光照下具有72小时的优异长期催化稳定性，明显优于先前工作中报道的稳定性。太阳辐照和PPC的显著协同效应，协同能力约为42%，主要可归因于太阳对催化剂床层的热效应，促进臭氧分解（从PPC的约0.18 g/g/h几乎提高到SEPPC的约0.52 g/g/h，提高近三倍）以产生更多氧化物种（如O自由基）并增强催化剂表面的催化氧化，以及太阳辐照驱动的高温下催化剂的自清洁能力。这项工作为利用丰富的可再生太阳能实现高性能和节能去除挥发性有机化合物开辟了一条合理途径。
