Calcium Single Atom Confined in Nitrogen-Doped Carbon-Coupled Polyvinylidene Fluoride Membrane for High-Performance Piezocatalysis

A piezoelectric polymer membrane based on single metal atoms was demonstrated to be effective by anchoring isolated calcium (Ca) atoms on a composite of nitrogen-doped carbon and polyvinylidene fluoride (PVDF). The addition of Ca-atom-anchored carbon nanoparticles not only promotes the formation of the β phase (from 29.8 to 56.3%), the most piezoelectrically active phase, in PVDF, but also introduces much higher porosity and hydrophilicity. Under ultrasonic excitation, the fabricated catalyst membrane demonstrates a record-high and stable dye decomposing rate of 0.11 min–1and antibacterial efficiencies of 99.8%. Density functional theory calculations reveal that the primary contribution to catalytic activity arises from single-atom Ca doping and that a possible synergistic effect between PVDF and Ca atoms can improve the catalytic performance. It is shown that O2molecules can be easily hydrogenated to produce ·OH on Ca-PVDF, and the local electric field provided by the β-phase-PVDF might enhance the production of ·O2–. The proposed polymer membrane is expected to inspire the rational design of piezocatalysts and pave the way for the application of piezocatalysis technology for practical environmental remediation.