Gas‐Phase Photoelectrocatalysis Mediated by Oxygen Ions for Uphill Conversion of Greenhouse Gases

Abstract

The present study reports a gas‐phase photoelectrochemical (GPEC) system in which photoanode and photocathode materials are coated on each side with a pellet of the oxygen‐ion conductor yttria‐stabilized zirconia (YSZ), where light irradiation is feasible on both sides. As a model gas‐phase reaction, we chose dry reforming of methane (DRM), which converts greenhouse gases into valuable syngas. Consequently, the stoichiometric DRM reaction proceeded in our GPEC system, indicating that the oxygen ions in a YSZ pellet act as mediators to link the redox reactions. It was also noted that UV light irradiation on the anodic side was more effective than that on the cathodic side, suggesting that the photogenerated holes in the anodic YSZ side activate methane molecules, while photogenerated electrons are injected into Rh nanoparticles to cause carbon dioxide reduction in the cathodic side. Our GPEC system converts greenhouse gases into valuable syngas by light irradiation.

Photocatalytic Methane Reforming: Recent Advances

“…CO2 continuously supplied oxygen into the lattice of SrTiO3, and the oxygen could react with methane to produce CO (Figure 36). To further investigate the photocatalytic DRM mechanism, Kushida et al constructed a unique gas-phase photoelectrochemical system (Figure 37) [52]. They used yttria-stabilized zirconia (YSZ) pellets as an electrolyte to conduct oxygen ions inside.…”

“…They used yttria-stabilized zirconia (YSZ) pellets as an electrolyte to conduct oxygen ions inside. On both sides To further investigate the photocatalytic DRM mechanism, Kushida et al constructed a unique gas-phase photoelectrochemical system (Figure 37) [52]. They used yttria-stabilized zirconia (YSZ) pellets as an electrolyte to conduct oxygen ions inside.…”

“…The reaction temperature was 600 °C and UV light was irradiated onto both sides. Reprinted from[52]. Copyright 2020 by John Wiley & Sons, Inc.…”

Highly Efficient Solar‐Driven Dry Reforming of Methane on a Rh/LaNiO3 Catalyst through a Light‐induced Metal‐To‐Metal Charge Transfer Process

“…But the existing research could only gain very low productivity, [ 33 ] and the utilization range of sunlight was limited to the ultraviolet area. [ 30,34–36 ]…”

Syngas production at a near-unity H2/CO ratio from photo-thermo-chemical dry reforming of methane on a Pt decorated Al2O3–CeO2catalyst

“…8 Despite the advantages of DRM and the reduced energy consumption compared with SMR, a relatively high temperature is still needed to initiate the traditional thermal-driven DRM process, [9][10][11] which, again, demands extensive energy input. 12,13 Further innovations to lower the energy demand are necessary.…”