Flammable gases produced by TiO₂ nanoparticles under magnetic stirring in water

The friction between nanomaterials and Teflon magnetic stirring rods has recently drawn much attention for its role in dye degradation by magnetic stirring in dark. Presently the friction between TiO₂ nanoparticles and magnetic stirring rods in water has been deliberately enhanced and explored. As much as 1.00 g TiO₂ nanoparticles were dispersed in 50 mL water in 100 mL quartz glass reactor, which got gas-closed with about 50 mL air and a Teflon magnetic stirring rod in it. The suspension in the reactor was magnetically stirred in dark. Flammable gases of 22.00 ppm CO, 2.45 ppm CH₄, and 0.75 ppm H₂ were surprisingly observed after 50 h of magnetic stirring. For reference, only 1.78 ppm CO, 2.17 ppm CH₄, and 0.33 ppm H₂ were obtained after the same time of magnetic stirring without TiO₂ nanoparticles. Four magnetic stirring rods were simultaneously employed to further enhance the stirring, and as much as 30.04 ppm CO, 2.61 ppm CH₄, and 8.98 ppm H₂ were produced after 50 h of magnetic stirring. A mechanism for the catalytic role of TiO₂ nanoparticles in producing the flammable gases is established, in which mechanical energy is absorbed through friction by TiO₂ nanoparticles and converted into chemical energy for the reduction of CO₂ and H₂O. This finding clearly demonstrates a great potential for nanostructured semiconductors to utilize mechanical energy through friction for the production of flammable gases.