Isolated Square‐Planar Copper Center in Boron Imidazolate Nanocages for Photocatalytic Reduction of CO₂ to CO

Abstract

Photocatalytic reduction of CO2 to value‐added fuel has been considered to be a promising strategy to reduce global warming and shortage of energy. Rational design and synthesis of catalysts to maximumly expose the active sites is the key to activate CO2 molecules and determine the reaction selectivity. Herein, we synthesize a well‐defined copper‐based boron imidazolate cage (BIF‐29) with six exposed mononuclear copper centers for the photocatalytic reduction of CO2. Theoretical calculations show a single Cu site including weak coordinated water delivers a new state in the conduction band near the Fermi level and stabilizes the *COOH intermediate. Steady‐state and time‐resolved fluorescence spectra show these Cu sites promote the separation of electron–hole pairs and electron transfer. As a result, the cage achieves solar‐driven reduction of CO2 to CO with an evolution rate of 3334 μmol g−1 h−1 and a high selectivity of 82.6 %.

Robust Biological Hydrogen‐Bonded Organic Framework with Post‐Functionalized Rhenium(I) Sites for Efficient Heterogeneous Visible‐Light‐Driven CO2 Reduction

“…During the photocatalysis, an electron transfer mechanism from excited [Ru(bpy) 3 ]Cl 2 ⋅6 H 2 O photosensitizer to HOF‐25‐Re is suggested by their matched energy levels (Figure S19) [18b, 20] . This point was further probed by the luminescent quenching experiment by adding the HOF‐25‐Re to a CH 3 CN solution of [Ru(bpy) 3 ]Cl 2 ⋅6 H 2 O and TIPA [21] . The emission at 605 nm is assigned to the metal ligand charge transfer (MLCT) excited state of [Ru(bpy) 3 ]Cl 2 (Figure 3 d), and the intensity is continuously reduced following the increased amount of HOF‐25‐Re, implying the occurrence of electron transfer from the excited state of photosensitizer to generate a reduced state of HOF‐25‐Re [18b, 26] .…”

“…[18b, 20] This point was further probed by the luminescent quenching experiment by adding the HOF-25-Re to aC H 3 CN solution of [Ru(bpy) 3 ]Cl 2 •6 H 2 Oa nd TIPA. [21] Theemission at 605 nm is assigned to the metal ligand charge transfer (MLCT) excited state of [Ru(bpy) 3 ]Cl 2 (Figure 3d), and the intensity is continuously reduced following the increased amount of HOF-25-Re,i mplying the occurrence of electron transfer from the excited state of photosensitizer to generate ar educed state of HOF-25-Re. [18b,26] In addition, the fitting of luminescent decay profile gives al ifetime (161.3 ns) for photosensitizer ( Figure S24).…”

Tailoring Crystal Facets of Metal–Organic Layers to Enhance Photocatalytic Activity for CO2 Reduction

“…[1] Thek ey issue therein is the development of highly efficient, selective,and inexpensive catalysts. [2] Forc rystalline catalysts,i ti sw ell known that different crystal facets primarily determine their catalytic performances by providing various active sites that affect the reaction energetics. [3] In regard to photocatalytic CO 2 reduction, Tang et al have achieved the control synthesis of Co 3 O 4 hexagonal platelets exposing (112) or (111) crystal facets, which can serve as catalysts for visible-light-driven CO 2 -to-CO conversion.…”

Metal–Organic Framework Decorated Cuprous Oxide Nanowires for Long‐lived Charges Applied in Selective Photocatalytic CO2 Reduction to CH4

“…2) Integrating Cu 2 O is capable of improving the visible-light absorption of MOFs (avoid using noble-metal photosensitizer); while MOFs with unsaturated coordinated single Cu sites can be the active components that reduce the energy barrier for CO 2 reduction and stabilize the reaction intermediates. [10][11][12][13][14][15][16] 3) 1D nanostructure contributes to a high surface-to-volume ratio, short lateral charge transport length, and low light-reflectivity, which usually demonstrates higher photocatalytic efficiencies. [17][18][19][20] 4) The framework of Cu 3 (BTC) 2 with good CO 2 and water-vapor absorption capacities can provide a dense reactant atmosphere for the redox reactions.…”