Efficient Visible-Light-Driven Carbon Dioxide Reduction using a Bioinspired Nickel Molecular Catalyst

Abstract[edit | edit source]

The study introduces a bioinspired nickel-based molecular catalyst, [Ni(N2S2)]Cl2 (NiN2S2), for photochemical catalytic reduction of CO2 under visible light. Combining the catalyst with [Ru(bpy)3]Cl2 as a photosensitizer and BIH as a sacrificial electron donor, the system achieved an 89% selectivity towards CO, with a turnover number (TON) of 7991 during 8 hours of irradiation. The process demonstrated high catalytic efficiency with a turnover frequency (TOF) of 1079 h⁻¹ and an apparent quantum yield (AQY) of 1.08%.

Summary[edit | edit source]

Inspired by natural enzymes, this work focuses on the development of a novel nickel catalyst for CO2 photoreduction. NiN2S2, designed with thiol and pyridine ligands, exhibited remarkable activity and selectivity in converting CO2 to CO. Control experiments confirmed the necessity of light, the catalyst, and sacrificial electron donors. Acidic co-substrates such as phenol further enhanced the reaction's efficiency without compromising selectivity. This study establishes NiN2S2 as a promising candidate for sustainable CO2 reduction under visible light.

Additional remarks[edit | edit source]

• The combination of sulfur and nitrogen ligands in NiN2S2 enhances its stability and catalytic efficiency.
• Acid additives, particularly phenol, significantly improve reaction rates, indicating a key role in CO2 stabilization and protonation steps.
• Further research is proposed to optimize ligand coordination and investigate intermediate reaction mechanisms.

Content of the published article in detail[edit | edit source]

• The synthesis and characterization of NiN2S2 using advanced analytical techniques like LC-HRMS and X-ray crystallography.
• The photocatalytic performance of NiN2S2 in reducing CO2 to CO under visible light, achieving high selectivity and efficiency.
• Mechanistic insights into the electron transfer process facilitated by the catalyst and photosensitizer.

Catalysts tested in this study[edit | edit source]

100990

([Ni(N2S2)]Cl2): A bioinspired nickel molecular catalyst.

Photosensitizer[edit | edit source]

Ru(bpy)3Cl2 100991 2,4,5,6-Tetrakis(diphenylamino)isophthalonitrile

Investigation[edit | edit source]

Key aspects investigated include:

• Catalyst stability and reusability.
• Impact of photosensitizer and electron donor concentrations on performance.
• Role of acidic co-substrates in improving CO2 reduction rates.

Table 01

	cat	cat conc [µM]	PS	PS conc [mM]	e-D	e-D conc [M]	.	.	solvent A	.	.	.	λexc [nm]	.	.	.	.
1.	Molecule:100990	1	Ru(bpy)3Cl2	0.7	BIH	0.02			MeCN				420
2.	Molecule:100990	1	Ru(bpy)3Cl2	0.7	TEA	0.02			MeCN				420
3.	Molecule:100990	1	Ru(bpy)3Cl2	0.7	TEOA	0.02			MeCN				420
4.	Molecule:100990	1	Molecule:100991	0.7	BIH	0.02			MeCN				420
5.	Molecule:100990	1	Ru(bpy)3Cl2	0.7	BIH	0.02			MeCN				420
6.	Molecule:100990	1	Ru(bpy)3Cl2	0.7	BIH	0.02			MeCN				420
7.	Molecule:100990	1	Molecule:100992	0.7	BIH	0.02			MeCN				420
8.	Molecule:100990	1	Ru(bpy)3Cl2	0.7	BIH	0.02			MeCN				420
9.	Molecule:100990	1	Ru(bpy)3Cl2	0.7	BIH	0.02			MeCN				420

Investigation-Name: Table 01Export

Further Information[edit | edit source]

• Control experiments demonstrated that light, the catalyst, and BIH were essential for activity.
• The reaction follows a reductive quenching pathway with efficient electron transfer from BIH to the photosensitizer and subsequently to the catalyst.

Sacrificial electron donor[edit | edit source]

In this Study, the experiments were done with the sacrificial electron donor BIH.