Recent Advances in Dry Reforming of Methane via Photothermocatalysis

Abstract

During the development of traditional industries, large amounts of greenhouse gases have been emitted due to the increasing consumption of fossil energy. CH4 and CO2 account for more than 98% of greenhouse gas emissions, and the conversion of CH4 and CO2 into high value-added chemicals has attracted extensive attention from both industry and academia. Dry reforming of methane (DRM) can co-convert CH4 and CO2 into syngas, which can be further converted into various value-added fuels and chemicals through Fischer-Tropsch synthesis. The dry reforming of methane into syngas by thermal catalysis provides an effective strategy for the consumption of both CH4 and CO2, which is beneficial for alleviating environmental problems such as global warming. However, a high-intensity energy input is needed at high temperatures owing to the thermodynamic limitations of the DRM reaction and catalyst instability caused by coke formation. Environmentally friendly photocatalytic technology can make the DRM reaction proceed under mild conditions. However, its development is greatly restricted owing to the low utilization rate of sunlight and low reaction conversion rate. Recently, photothermocatalysis has been widely used in various fields. Many studies have shown that under relatively mild conditions, photothermocatalysis of DRM can achieve promising catalytic performance and effectively convert solar energy into chemical energy. Photothermocatalysis can greatly increase the reaction rate of photocatalytic DRM without a high energy input. In addition, the introduction of light is beneficial for the thermal catalysis of DRM by reducing the reaction activation energy, inhibiting coke formation, and reversing the water-gas shift reaction. In this paper, the advantages and disadvantages of thermal catalysis, photocatalysis, and photothermal catalysis of DRM are first discussed. Then, recent research progress in photothermocatalysis of the DRM reaction, especially the application of different metal-based catalysts (Ni, Pt, Rh, Ru, and Co) is summarized. Localized surface plasmon resonance effects, types of carriers, elimination of coke formation, and suppression of the reverse water-gas shift reaction are briefly mentioned. Finally, the future challenges and new perspectives on the photothermocatalysis of DRM are highlighted, including high utilization of sunlight, catalyst long-term stability, reactor optimization, and the photothermocatalytic mechanism.

Recent Advances in the Conversion of Methane to Syngas and Chemicals via Photocatalysis

“…The harsh reaction conditions also lead to rapid deactivation due to catalyst sintering and carbon deposition. [30,[42][43][44] In Ruitao contrast, photocatalytic methane reforming can occur under mild reaction conditions, which not only effectively reduces energy consumption but also avoids the catalyst deactivation. In recent years, significant progress has been achieved in catalyst development for photocatalytic reforming of CH 4 as summarized in Table 1.…”

Promoted CF4 Decomposition via Enhanced Tricoordinated Al Active Sites

“…At present, various methods, including plasma, combustion, and catalytic hydrolysis, have been developed for the decomposition methods of CF 4 . − Among them, catalytic hydrolysis is regarded as a promising method owing to its capability of high decomposition efficiency and large gas flux. − Al-based materials with abundant acidic sites are the most used catalysts in decomposition of CF 4 . − Song et al reported that the more the Lewis acid sites on the surface of Al-based catalysts, the stronger the ability to decompose CF 4 . Zhang et al found that the strong Lewis acid site of unsaturated tricoordinated Al (Al III ) was the main active site for CF 4 decomposition, indicating that more Al III active sites represent higher CF 4 decomposition activity.…”