Production of Methanol as a Fuel Energy from CO₂ Present in Polluted Seawater - A Photocatalytic Outlook

Abstract

The production of methanol by photocatalytic reduction of the CO2 present in the different polluted seawater systems was explored using P–25, C/TiO2, and Cu-C/TiO2 under both UV and sunlight. Both C/TiO2 and Cu-C/TiO2 were synthesized by the sonicated sol-gel method. The prepared photocatalyst demonstrated maximum efficiency when the dosage of photocatalysts was 1g/L and the doping level was 3wt% of copper. The maximum methanol yields of two observed polluted seawater systems were 2910 μmol/g and 2250 μmol/g after 5 hour illumination of UV light. However, the 5 hour natural sunlight illumination generated the yield of 990 μmol/g and 910 μmol/g of methanol. The observed results demonstrated that band gap narrowing of the photocatalyst by carbon modification and the restriction of electron-hole pair combination by copper doping both greatly enhanced the photocatalytic reduction of CO2 to methanol under both UV and natural sunlight.

Carbon Nitride‐Based Ruthenium Single Atom Photocatalyst for CO2 Reduction to Methanol

“…In the case of nanomaterials, the limited fraction of the exposed active sites onto the surface of metal nanoparticles in the catalysis reactions results in comparatively lackluster catalytic performance. [ 15 ] Previous studies have reported CO 2 reduction catalyzed by nanomaterials [ 16 ] and nanowires [ 17 ] under photochemical conditions. [ 18,19 ] With the poor metal atomic utilization, the true catalytic activity of metal component is significantly reduced.…”

Photocatalytic conversion of carbon dioxide, methane, and air for green fuels synthesis

“…In 2018, Kavil et al 3 conducted an experiment involving the production of CH 3 OH from CO 2 using two samples of polluted seawater. The system used TiO 2 (P25), C/TiO 2 , and Cu–C/TiO 2 doped catalysts under UV and visible light.…”

“…CO 2 emissions are mainly released from vehicles, heavy industries, chemical plants, and burning fossil fuels. 3 As shown in Table 1, the industrial sector is the third largest emitting greenhouse gases in the US, with 24% greenhouse gas emissions. Table 2 illustrates that in 2020, all economic sectors collectively contributed 79% of CO 2 emissions and 11% of CH 4 emissions.…”

“…5 Among all photocatalysts, TiO 2 is considered a highly attractive option due to its strong reducing and oxidizing properties, low toxicity, and photostability. 3 However, its large band gap (3.2 eV) limits its ability to absorb visible light. Thus, modifications through doping with metals and metal-oxides are required.…”

Direct catalytic production of dimethyl ether from CO and CO2: A review

“…Unfortunately, a major drawback of TiO2 is the rapid combination of electron-hole pairs. It has been reported that metal cation doping on TiO2 catalysts can reduce electron-hole pair composition [106]. To accomplish the improved photoactivity, many researchers tried to modify TiO2 by doping with metal.…”