Graphene oxide as a promising photocatalyst for CO₂to methanol conversion

Abstract

Photocatalytic conversion of carbon dioxide (CO(2)) to hydrocarbons such as methanol makes possible simultaneous solar energy harvesting and CO(2) reduction, two birds with one stone for the energy and environmental issues. This work describes a high photocatalytic conversion of CO(2) to methanol using graphene oxides (GOs) as a promising photocatalyst. The modified Hummer's method has been applied to synthesize the GO based photocatalyst for the enhanced catalytic activity. The photocatalytic CO(2) to methanol conversion rate on modified graphene oxide (GO-3) is 0.172 μmol g cat(-1) h(-1) under visible light, which is six-fold higher than the pure TiO(2).

Effect of temperature on the structural, linear, and nonlinear optical properties of MgO-doped graphene oxide nanocomposites

“…Therefore, the optical band-gap of GO may be anywhere between semiconducting 1 eV and as high as 4.5 eV [26]. From the Tauc plot shown in Figure 3A for the GO sample, the optical band-gap value can be measured in the range of 3.3-4.2 eV, which has good agreement with the values reported for GO in the literature [27][28][29].…”

Graphene Oxide as An Efficient Photocatalyst For Photocatalytic Reduction of CO2 Into Solar Fuel

“…Response of GO in λ > 400 nm can be attributed to n→π* transition of C=O [29]. Optical band gap of GO calculated by Kubelka-Munk function using Tauc plot was 1.3 eV as shown in Figure 2(b).…”

“…Moreover, conduction band potential of GO is -0.79 V (vs. Normal Hydrogen Electrode (NHE)) which is more negative than reduction potential of CO2/CH4 (-0.24 V) and CO2/CH3OH (-0.38 V), respectively. Valence band potential of GO is 4 V (vs. NHE) which is higher than oxidation potential of H2O/O2, H + (-0.82) [29]. Although, GO can be potential photocatalyst for the CO2 reduction into CH4 and CH3OH, stability of photocatalyst is to be improved.…”

“…Meanwhile, GO which is oxygenated graphene sheets, comprise of covalently and non-covalently bonded oxygen functional groups such as epoxy, phenolic and carboxylic group [29]. In past few years, graphene based photocatalytic semiconductors have widely reported for CO2 reduction due to their excellent activity [30].…”

Photomethanation of Gaseous CO2 over Ru/Silicon Nanowire Catalysts with Visible and Near‐Infrared Photons

“…Lo et al also demonstrated the photoreduction of CO 2 with H 2 over ZrO 2 in a circulating photocatalytic reactor 22. More recently, CO 2 photoreduction to methanol in a hydrogen environment has been reported to occur over graphene oxide23 and zinc‐copper‐gallium layered double hydroxide catalysts 24. Also, very recently Hoch et al have shown that hydroxylated indium oxide nanoparticles are active for the photoreduction of CO 2 to CO 25…”