Plasma-Assisted Photocatalysis of CH₄ and CO₂ into Ethylene

Abstract

Oxidative coupling of methane (OCM) using CO 2 as the oxidant is a potential advancement for methane conversion and greenhouse gases reduction. However, the reaction is usually limited by both high energy consumption and strict reaction condition. Here, we report, for the first time, photoinduced efficient ethylene (C 2 H 4 ) and CO production by OCM over TiO 2 -supported Ag nanoparticles at mild conditions. The success relies on a synergy coupling visible-light-induced strong surface plasma resonance (SPR) effect localized on Ag(0), ultraviolet-light-induced photoelectric effect on TiO 2 , and the separated adsorption of CO 2 and CH 4 on TiO 2 and Ag. The yields of CO and C 2 H 4 reach 1149 and 686 μmol•g −1 •h −1 , respectively, under simulated solar irradiation. The origination of carbon-based gas products from CO 2 and CH 4 is also certified by a 13 C isotope-labeled experiment. This work presents a new and ideal route of photocatalytic OCM reaction for C 2 H 4 and CO production by coupling both SPR and photoelectric effects.

MgO and Au nanoparticle Co-modified g-C3N4 photocatalysts for enhanced photoreduction of CO2 with H2O

“…9(c) shows several adsorption species generated under the irradiation due to the CO2 interaction with the photocatalyst in the region of 1300-1800 cm -1 . The bands at 1507, 1324, and 1404 cm -1 can be attributed to the adsorption of CO2 in the forms of monodentate carbonate (m-CO3 2-), bidentate carbonate (b-CO3 2-), and bicarbonate (HCO3 -), respectively [61][62][63]. The peaks displayed a slight enhancement with increasing irradiation time.…”

Alternative Oxidants for the Catalytic Oxidative Coupling of Methane

“…Although several publications have reported photocatalytic reactions between CH 4 and CO, most are focused on reforming and do not produce any C 2 products [55] . However, Li and co‐workers reported significant ethylene yields over a 1 wt % Ag/TiO 2 catalyst at room temperature using a plasma‐assisted photocatalytic system [56] . For example, under optimized conditions, the authors observed an ethylene yield rate of about 7 μmol g −1 /h×10 2 , compared to 12 μmol g −1 /h×10 2 for CO. TPD experiments suggested that CO 2 adsorbs on TiO 2 while CH 4 adsorbs on the Ag sites.…”

Photocatalytic and Thermocatalytic Conversion of Methane

“…There have been many reports on the production of high‐value chemicals or syngas from photocatalytic CRM reactions. [ 129–132 ]…”