Enhancing CO2 to Alcohol Conversion: Powerful Photocatalysts Based on TiO2–Cu(I)-Iodine-Pyridine One-Dimensional Coordination Polymers

TL;DR

Researchers developed new photocatalysts that efficiently convert CO2 into alcohol, with one variant showing high stability and selectivity for methanol production.

Contribution

A novel class of 1D Cu(I)-iodide-pyridine coordination polymers is introduced for enhanced CO2 photoreduction to alcohols.

Findings

TiO2@5%CP4 achieved methanol production at 894 μg·g_cat–1·h–1, outperforming TiO2@3%CuO.

TiO2@5%CP4 maintained stable performance for 10 hours without degradation.

Hydrogen bonding from amine substituents in CP4 improved CO2 interaction and stability.

Abstract

Coordination polymers
(CPs) are promising materials for environmental
applications, particularly in catalysis, due to their flexible structures,
tunable electronic properties, and adaptable surface chemistry. This
study reports the one-step, room-temperature synthesis of five 1D
Cu­(I)-iodide-pyridine based CPs with the general formula [CuI­(L)]
n
, where L represents different pyridine derivatives:
pyridine (CP1), 3-methylpyridine (CP2),
4-methylpyridine (CP3), 2-amino-4-methylpyridine (CP4), and 2-chloro-4-methylpyridine (CP5). All
of the compounds exhibit band gap energies around 3 eV, making them
suitable candidates for photocatalytic applications. Indeed, the study
investigates the photoreduction of CO2 to alcohols using
a heterogeneous photocatalytic system consisting of TiO2 and varying proportions of CPs. The reactor design enables the rapid
removal of produced alcohols, preventing them from being oxidized
by TiO2 as sacrificial materials and thus achieving near-zero
net alcohol production. The optimal TiO

2

@CP mixture, TiO

2

@5%CP4, demonstrated higher chemical stability
due to the amine substituent on the pyridine, which facilitates hydrogen
bonding between CP chains, and an enhanced ability to interact with
CO2, as confirmed by adsorption experiments and DFT calculations.
The optimized mixture achieved selective methanol production of 894
μg·g cat –1·h –1, significantly surpassing the benchmark photocatalytic system TiO

2

@3%CuO (318 μg·g
cat –1·h –1). Furthermore, TiO

2

@5%CP4 maintained
stable photocatalytic performance over 10 h without noticeable degradation.

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