Piezo-Photocatalytic Synergy in BiFeO 3 @COF Z-Scheme Heterostructures for High-Efficiency Overall Water Splitting.

Solar-driven overall water splitting is an ideal way to generate renewable energy while still challenging. For the first time, this work combined covalent organic frameworks (COFs) and piezoelectric material by covalent linkages to form Z-scheme core@shell heterostructure for overall water splitting. Benefiting from the synergistic effect between the polarized electric field and photo-generated charges, as well as the precise adjustment of shell thickness, the carrier separation and utilization efficiency is greatly improved. The optimal BiFeO 3 @TpPa-1-COF photocatalyst revealed hydrogen (H 2 ) and oxygen (O 2 ) production rates of 1416.4 and 708.2 μmol h -1  g -1 under the excitation of ultrasonication coupled with light irradiation, which is the best performance among various piezo- and COF-based photocatalysts. This provides a new sight for the practical application of highly efficient photocatalytic overall water splitting.