An Artificial Photosystem of Metal-Insulator-CTF Nanoarchitectures for Highly Efficient and Selective CO2 Conversion to CO.

Abstract

It is of pivotal significance to explore robust photocatalysts to promote the photoreduction of CO2 into solar fuels. Herein, an intelligent metal-insulator-semiconductor (MIS) nano-architectural photosystem was constructed by electrostatic self-assembly between cetyltrimethylammonium bromide (CTAB) insulator-capped metal Ni nanoparticles (NPs) and covalent triazine-based frameworks (CTF-1). The metal-insulator-CTF composites unveiled a substantially higher CO evolution rate (1254.15 μmol g-1 h-1 ) compared with primitive CTF-1 (1.08 μmol g-1 h-1 ) and reached considerable selectivity (98.9 %) under visible-light irradiation. The superior photocatalytic CO2 conversion activity over Ni-CTAB-CTF nanoarchitecture could be attributed to the larger surface area, reinforced visible-light response, and CO2 capture capacity. More importantly, the Ni-CTAB-CTF nanoarchitecture endowed the photoexcited electrons on CTF-1 with the ability to tunnel across the thin CTAB insulating layer, directionally migrating to Ni NPs and thereby leading to the efficient separation of photogenerated electrons and holes in the photosystem. In addition, isotope-labeled (13 CO2 ) tracer results verified that the reduction products come from CO2 rather than the decomposition of the photocatalysts. This study opens a new avenue for establishing a highly efficient and selective artificial photosystem for CO2 conversion.