CO₂ Dominated Bifunctional Catalytic Sites for Efficient Industrial Exhaust Conversion

Abstract

Converting industrial exhaust into valuable chemicals is crucial for sustainable economic development. Direct CO2 photoreduction from real flue gas is an ideal clean and promising way, until now, without success. Here, photoreduction of exhaust gas from the power plant by Ni bridged COF (Ni@TPHH‐COF) is shown. Under visible light, syngas is produced with CO output reaching 2.1 mol kg−1 h−1. The ideal conversion of flue gas is up to 672 L kg−1 h−1. Of note, the system exhibits appealing yield and selectivity under 0.5–40% CO2 and AQY achieves 3.96% under 10% CO2, ranking among the highest value of reported photocatalysts. Mechanism studies suggest CO2 plays a dual function as both a component of a catalytic site and a reactant, which can not only selectively enrich CO2 in catalytic sites but improve reaction rate significantly. This CO2‐dominated bifunctional site prolongs electrons lifetime, stabilizes intermediates, and reduces free energy of reduction under diluted CO2.

Copper-Based Metal–Organic Framework with a Tetraphenylethylene-Tetrazole Linker for Visible-Light-Driven CO2 Photoconversion

“…The conduction band minimum (CBM) position of CUST-804 is determined by M–S curves (Figure B). According to the positive slope of the M–S curves of CUST-804 , the n-type characteristic is determined. , The flat-band potential is measured by the M–S curve, and it is known that the CB of the n-type semiconductor is nearly 0.1 V negative compared to the flat-band potential. , After testing, the flat-band potential of CUST-804 is −0.68 eV versus Ag/AgCl (≈−0.48 eV vs NHE). Accordingly, the CB value of CUST-804 is measured as −0.58 eV versus NHE.…”

“…57,58 The flat-band potential is measured by the M−S curve, and it is known that the CB of the n-type semiconductor is nearly 0.1 V negative compared to the flat-band potential. 59,60 After testing, the flat-band potential of CUST-804 is −0.68 eV versus Ag/AgCl (≈−0.48 eV vs NHE). Accordingly, the CB value of CUST-804 is measured as −0.58 eV versus NHE.…”

Metalated covalent organic frameworks: from synthetic strategies to diverse applications

“…Examples of metalated COF-based photocatalytic CO 2 RR to CO are summarized in Table 7 to provide a direct and clear understanding of the structure-function relationship of metalated COFbased photocatalysts. 141,186,187,212,240,241,251,575,601-605, [607][608][609][610][611][612][613] Metalated COFs for photocatalytic CO 2 RR to formic acid or formates will be discussed next. In 2019, Lan and co-workers reported a series of transition metal-loaded DQTP-COF-M (M = Co, Ni, Zn).…”

“…Examples of metalated COF-based photocatalytic CO 2 RR to CO are summarized in Table 7 to provide a direct and clear understanding of the structure–function relationship of metalated COF-based photocatalysts. 141,186,187,212,240,241,251,575,601–605,607–613…”

Photocatalytic reduction of low-concentration CO2 by metal–organic frameworks

“…1 At present, anthropogenic CO 2 comes mainly from industrial waste gases with a CO 2 concentration of 5-25%, such as coal-fired power plants. [2][3][4] Photo-induced CO 2 reduction to value-added chemical stocks and fuels has been proposed as a promising avenue to alleviate the energy crisis and environmental problems. However, the high dissociation energy of CO 2 molecules and the kinetic challenge of the multi-electron reaction restrict the high selectivity of CO 2 reduction.…”