Introducing an external photo field would effectively enhance electrocatalysis such as electrocatalytic CO 2 reduction reaction (CO 2 RR), but suffering from the limited utilization efficiency of the photo-generated carriers. To address this challenge, a research team led by Professor Yuan-Biao Huang at the Fujian Institute of Research on the Structure of Matter, Chinese Academy of Science, has successfully encapsulated metal halide perovskite quantum dots (e.g. CsPbBr 3 ) with high light-absorption coefficients, into a cobalt-porphyrin-based covalent–organic frameworks (COFs) host (COF-366-Co). The synthesized perovskite-COF composite material, effectively improve the performance of the photocoupled electrochemical CO 2 RR.
Powder X-ray diffraction (PXRD) patterns, transmission electron microscopy (TEM) and high-resolution TEM (HR-TEM) analyses indicated that the encapsulation of CsPbBr 3 on COF-366-Co was successful. The trend of photo-generated electron transfer from CsPbBr 3 to COF-366-Co framework is first identified by their VB and CB energy levels. The X-ray photoelectron spectroscopy (XPS) results and fluorescence quenching experiments further validated the real existence of electron transfer channel in CsPbBr 3 @COF-X. Such a newly formed electron transfer channel could significantly increase charge separation efficiency and prolong the excited-state lifetime of CO 2 reduction activator Co-Por, which in turn promises to continuously decrease the RDS energy of the electrocatalytic CO 2 RR. Consequently, the optimal CsPbBr 3 @COF-2 exhibited a CO Faradaic efficiency of 93.4% at −0.7 V vs. reversible hydrogen electrode (RHE), and achieved a CO partial current density ( j CO ) of 7.8 mA cm −2 with a turnover frequency (TOF) of 3395.5 h −1 at −0.9 V under visible light, all of which far exceeded the values recorded in the dark. Briefly, this work provides a new avenue to design high-performance photocoupled electrocatalytic materials via enhancing the interfacial electric field.
Science China Chemistry
Experimental study