Methane Conversion Under Mild Conditions Using Semiconductors and Metal-Semiconductors as Heterogeneous Photocatalysts: State of the Art and Challenges

Abstract

The processes currently used in the chemical industry for methane conversion into fuels and chemicals operate under extreme conditions like high temperatures and pressures. In this sense, the search for methane conversion under mild conditions remains a great challenge. This review aims to summarize the use semiconductors and metal-semiconductors as heterogeneous photocatalysts for methane conversion under mild conditions into valuable products. First, a brief presentation of photochemical conversion of methane is provided and then the focus of this review on the use of heterogeneous photocatalysts for methane conversion are described. Finally, the main challenges and opportunities are discussed.

Theoretical Insights into Methane Activation on Transition-Metal Single-Atom Catalysts Supported on the CeO2(111) Surface

“…For example, the indirect route involves the production of synthesis gas (CO + H 2 ) from methane by catalytic steam reforming and dry reforming, which can then be used in the well-known Fischer–Tropsch synthesis process and also for methanol (CH 3 OH) synthesis . In contrast, the direct route involves the conversion of methane to chemicals such as methanol, ethane, and ethylene, which is a challenge. For both routes, the conversion process begins with the activation of methane, which leads to the cleavage of the C–H bond; however, due to the high stability of methane, the C–H activation is a major challenge, and hence, it is mandatory to use catalysts …”

Methane conversion coupled with hydrogen production from water using Au/Ga2O3 photocatalysts prepared by different methods

“…1,2 Steam reforming of methane (SRM) (CH 4 + 2H 2 O / 4H 2 + CO 2 ) is the main process of methane conversion into hydrogen, and this reaction occurs over the temperature range of 970-1000 K and pressures up to 3.5 MPa. 3 With the demand for a decrease in the use of non-renewable energy, the use of solar energy would be a new stimulus for its replacement. 4,5 Hydrogen has been highlighted as a possible source of clean energy in the energy transition.…”

Oriented External Electric Fields Regurating the Reaction Mechanism of CH4 Oxidation Catalyzed by Fe(IV)-Oxo-Corrolazine: Insight from Density Functional Calculations

“…In 2021, the United Nations called for a reduction in methane emission in the atmosphere, aiming to reduce global methane emission by 30% by the end of the century ( Brenneis et al, 2022 ). Therefore, if an efficient method can be found to convert methane into methanol efficiently and economically, it can not only solve the difficulty of methane transportation, but also provide a large number of cheap raw materials for industrial production and reduce methane pipelines leakage ( Park et al, 2019 ; Yan et al, 2020 ; Januario et al, 2021 ), thus providing feasible methods for methane emission reduction.…”