Friction energy harvesting on bismuth tungstate catalyst for tribocatalytic degradation of organic pollutants

Mechanical energy as the green and sustainable energy source widely distributes in natural environment. In this paper, we successfully realize the conversion of mechanical energy through a friction route on the tribocatalyst of Bi2WO6. Under magnetic stirring, the friction between the PTFE-sealed magnetic bar and the catalyst particles resulted in the electron transfer crossing the contact interface, in which PTFE accepted the electrons and simultaneously the holes were left on the catalyst. The positively charged catalyst was demonstrated through electrostatic attraction and repulsion tests. Like photocatalytic process, the holes on the valence band of Bi2WO6 have strong oxidative ability that can efficiently oxidize organic pollutants. The tribocatalytic tests showed that the Bi2WO6 could eliminate organic dyes under magnetic stirring in dark, and we could further optimize the tribocatalytic performance via regulating the size of magnetic bar and reactor material. Finally, a high stability of tribocatalysis was revealed by the multiple tests. This work not only develops a green tribocatalysis strategy to oxidative purification of organic pollutants, but also provides a possible pathway to convert mechanical energy in environment to chemical energy, such as potential applications in environmental remediation and sustainable energy.