Solar-Enhanced Plasma-Catalytic Oxidation of Toluene over a Bifunctional Graphene Fin Foam Decorated with Nanofin-like MnO2

Bo, Zheng, Yang, Shiling, Kong, Jing, Zhu, Jinhui, Wang, Yaolin ORCID: 0000-0003-1932-9810, Yang, Huachao, Li, Xiaodong, Yan, Jianhua, Cen, Kefa and Tu, Xin ORCID: 0000-0002-6376-0897
(2020) Solar-Enhanced Plasma-Catalytic Oxidation of Toluene over a Bifunctional Graphene Fin Foam Decorated with Nanofin-like MnO2. ACS Catalysis, 10 (7). pp. 4420-4432.

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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 MnO2/GFF (bifunctional graphene fin foam) catalyst. The bifunctional GFF, serving as both the catalyst support and light absorber, is decorated with MnO2 nanofins, forming a hierarchical fin-on-fin structure. The results show that the MnO2/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-2). 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 CO2 selectivity by 36-63%, reaching ∼93% for toluene conversion and ∼83% for CO2 selectivity at a specific input energy of ∼350 J L-1, 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-1, ∼57% higher than that using the PPC process without solar irradiation (8.1 g kWh-1), whereas the energy consumption of the SEPPC process is reduced by 35-52%. Moreover, the MnO2/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 gO3 g-1 h-1 for PPC to ∼0.52 gO3 g-1 h-1 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.

Item Type: Article
Uncontrolled Keywords: volatile organic compounds, plasma-catalysis, toluene oxidation, solar thermal conversion, hierarchical fin-on-fin structure
Depositing User: Symplectic Admin
Date Deposited: 30 Mar 2020 10:32
Last Modified: 18 Jan 2023 23:56
DOI: 10.1021/acscatal.9b04844
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