Bifunctional RbBiNb2O7/poly(tetrafluoroethylene) for high-efficiency piezocatalytic hydrogen and hydrogen peroxide production from pure water

Overall water splitting initiated by the green energy is a challenging yet promising route to address the worldwide environmental and energy issues. Herein, we report the implementation and unraveling of the piezoelectric effect of RbBiNb2O7/poly(tetrafluoroethylene) (RBNO/PTFE) on promoting the thermodynamically favorable 2e- reaction to significantly enhance their overall water splitting (i.e., simultaneously producing H2O2 and H2) via piezocatalysis. HRTEM, XPS and FTIR results confirm the successful preparation of RBNO/PTFE. The piezo-responses of RBNO/PTFE are uncovered by PFM. Remarkably, exceptional H2 and H2O2 production rates (i.e., 260.79 and 219.23 μmol g-1h-1, respectively) are achieved over RBNO/PTFE in pure water without cocatalysts upon the ultrasonic excitation, far exceeding those of pure RBNO and PTFE. Specifically, the piezoelectric polarization of PTFE causes the band tilt of RBNO, leading to the energy match between the required redox potential and the band structure of RBNO towards dynamically favorable H2 and ·OH mediated H2O2 generation. In addition, the hydrophobic modification of PTFE over RBNO makes water oxidation reaction occur toward the H2O2 production. Given the diversity of materials possessing the mechanical-force-to-chemical-energy conversion, this work may provide a robust way to underpin future advances in the catalytic renewable-energy production.