Continuous Flow System for Highly Efficient and Durable Photocatalytic Oxidative Coupling of Methane

Abstract

Photocatalytic oxidative coupling of methane (OCM) into value-added industrial chemicals offers an appealing green technique for achieving sustainable development, whereas it encounters double bottlenecks in relatively low methane conversion rate and severe overoxidation. Herein, we engineer a continuous gas flow system to achieve efficient photocatalytic OCM while suppressing overoxidation by synergizing the moderate active oxygen species, surface plasmon-mediated polarization, and multipoint gas intake flow reactor. Particularly, a remarkable CH4 conversion rate of 218.2 μmol h–1 with an excellent selectivity of ∼90% toward C2+ hydrocarbons and a remarkable stability over 240 h is achieved over a designed Au/TiO2 photocatalyst in our continuous gas flow system with a homemade three-dimensional (3D) printed flow reactor. This work provides an informative concept to engineer a high-performance flow system for photocatalytic OCM by synergizing the design of the reactor and photocatalyst to synchronously regulate the mass transfer, activation of reactants, and inhibition of overoxidation.

Particle Size-Dependent Charge Transfer Dynamics for Boosting CO2 Photoreduction over Ag/TiO2 Heterojunction

“…Additionally, the light enhancement mechanism of Ag NPs in PCO 2 R process with different particle sizes for localized and nonlocalized regions was also investigated by ultrafast transient absorption , and in situ techniques . Also, to investigate thermal electron transfer pathway in the deep LSPR process, Au/TiO 2 /W 18 O 49 Z-scheme heterojunction were constructed to prepare CH 4 highly selective catalysts where in situ spectroscopic characterization combined with theoretical calculations revealed the oxygen-activated, surface plasma-mediated CH 4 activation over the Au/TiO 2 photocatalysts . However, existing studies on the particle size of the metal plasma in Schottky junctions focus on the change of the particle size on the redox potential as well as the energy band structure, which affects the process of PCO 2 R .…”

Interstitial Zinc Defects Enriched ZnO Tuning O2 Adsorption and Conversion Pathway for Superior Photocatalytic CH4 Oxygenation

“…Methane (CH 4 ) as the main components of natural gas abundant in the earth plays an important role in industrial production. − Upgrading CH 4 to high value oxygenates not only provides the required raw material intermediates for the chemical industry but also effectively reduces the transportation cost of CH 4 . , Photocatalysis as an advanced green technology could utilize light energy to trigger high reactive energy barrier reactions, providing a method for directly converting CH 4 into liquid oxygenates. , Nevertheless, the inherent high bond energy and low polarization of the C–H bond seriously hinder the efficiency of CH 4 conversion. − Moreover, liquid oxygenates are more prone to overoxidation to CO 2 than CH 4 . − Therefore, searching for photocatalysts with high efficiency and selectivity to liquid oxygenates is the core of CH 4 conversion.…”