Jih-Jen Wu1,Li-Che Chueh1
National Cheng Kung Univ1
Jih-Jen Wu1,Li-Che Chueh1
National Cheng Kung Univ1
Cyanamide-functionalized potassium poly(heptazine imide) (CFKPHI) which exhibits the abilities of light harvesting and photoelectron storage for solar energy conversion is a new class of two-dimensional (2D) carbon nitrides. In this work, CFKPHIs were synthesized by ionothermal treatment of supramolecular complexes of various nitrogen-rich organic compounds. Solid-state nuclear magnetic resonance characterizations reveal that in addition to the cyano defect in CFKPHI, intrinsic defect modified CFKPHIs, including C-H group-functionalized and carbon vacancy-modified CFKHPIs, can be tailored by the compositions of the supramolecular complexes. The C-H group-functionalized and carbon vacancy-modified CFKHPIs demonstrate comparable photocatalytic activities for hydrogen evolution under AM 1.5G (100 mWcm<sup>-2</sup>) illumination in the presences of the Pt nanoparticle cocatalyst and the hole scavenger of triethanolamine (TEOA), which are 3-fold enhanced compared to the photocatalytic activity of CFKPHI. The dark photocatalytic performances of the two defect-modified CFKPHIs were also examined in this work. The CFKPHI photocatalysts in TEOA aqueous solution were irradiated using AM 1.5G (100 mWcm<sup>-2</sup>) for 2 h, the Pt precursor was injected into the solution as soon as the irradiation was turned off. The delayed H<sub>2</sub> productions over the C-H group-functionalized and carbon vacancy-modified CFKPHIs are 14-fold and 194-fold higher than that over CFKPHIs. The photophysical properties of light-storing carbon nitrides are variable by modifying the microstructure of CFKPHIs towards efficient solar energy storage and conversion. The influences of chemical and electronic structures on the solar energy storage and photocatalytic activity of KPHIs will be discussed in this presentation.