Cu-titanium oxide nanorod system has been developed for the conversion of polyols and sugars into methanol and syngas under UV light irradiation at room temperature.
Methanol is an industrially important liquid fuel, having been identified as a clean alternative to gasoline and diesel. Moreover, methanol is used for the production of chemical building blocks such as ethylene and propylene, and is itself a fundamental starting material and solvent in chemical research.
Currently, methanol is industrially produced from fossil fuels. In light of global warming, research on production of methanol from renewable and abundant carbon resources such as biomass has taken on greater impetus.
Traditionally, the conversion of biomass into bio-methanol, dubbed liquid sunshine, has to go through an intermediate called syngas, which is a mixture of CO and H2. Furthermore, this reaction has to take place at high temperatures (700–1000°C) and generates large amounts of waste CO2 and hydrocarbons, greatly reducing the efficiency of the process.
Recently, a research group led by Wang Feng from Dalian Institute of Chemical Physics, Chinese Academy of Sciences, has developed a photocatalytic system that can directly produce methanol from biomass.
The system consists of Cu atoms dispersed on titanium oxide nanorods (Cu/TNR), and is effective for the conversion of polyols and sugars directly into methanol under UV light irradiation at room temperature.
Under these conditions, the system also produces syngas, but the CO/CO2 selectivity can be fine-tuned up to 90 percent CO by decreasing the water concentration to five percent and the copper loading to 0.01 weight percent.
Mechanistic studies revealed that the high activity of the Cu/TNR system may be attributed to its numerous defects caused by missing oxygen atoms, which results in the C–C bond cleavage of polyols to methanol becoming more thermodynamically favourable.
The authors also proved that cellulose and even raw beech sawdust could be converted into methanol/syngas with this system after pre-treatment. The study was published in Nature Communications. [APBN]