Modulating stacking mode and molecular polarization in CTF/molecule heterojunction for meliorating photocatalytic CO2 conversion with nearly 100% CO selectivity.

Due to the polorization effect of D-π-A TAPT and fast charge delivery in AA-CTF of AA-CTF/TAPT, the Z-Scheme heterojunction provides an efficacious carrier migration for improving photocatalytic CO 2 RR. [Display omitted] • D-π-A TAPT and non-D-A TAPB molecules are integrated with CTF, respectively. • The interfacial polarization in AA-CTF/TAPT highly devote to charge separation. • the fast charge transfer channel in AA-CTF is conductive to carrier transport. • The optimal CO 2 RR conducted by AA-CTF/TAPT gives nearly 100% reaction selectivity. Herein, two conjugated molecules, i.e., D-π-A TAPT and non-D-A TAPB, are finely designed to incorporate with covalent triazine framework (CTF) in A-A and A-B stacking mode via π-π interaction, respectively. The transient photocurrent response of the generated AA-CTF/TAPT Z-Scheme heterostructure is 1.14 × 10-7 A, significantly higher than that of the other two metal-free heterostructures (AA-CTF/TAPB and AB-CTF/TAPT). The promoted photocarrier transportation is attributed to strong polarization (dipole moment = 2.634 D) imposed by the D-π-A effect in TAPT that motivates the interfacial charge separation, and the coexisting charge transfer channel built by the ordered A-A stacking mode in AA-CTF that expedites the charge delivery. The photocatalytic CO 2 conversion conducted by AA-CTF/TAPT gives the optimal CO conversion rate as 7.47 μmol·g−1·h−1, and with nearly 100 % product selectivity obtained, which is attributable to the lower energy barrier of CO desorption barrier (−1.07 eV) rather than that of CHO* formation (1.52 eV) for generating CH 4. [ABSTRACT FROM AUTHOR]