Photocatalytic CO₂ Reduction by Re(I) Polypyridyl Complexes Immobilized on Niobates Nanoscrolls

Abstract

Immobilization of Re­(I) CO2 reduction photocatalysts on metal oxide surfaces is an interesting approach to improve their stability and recyclability. In this work, we describe the photocatalytic activity of two Re­(I) complexes (fac-[Re­(NN)­(CO)3(Cl)], NN = 4,4'-dicarboxylic acid-2,2'-bipyridine, 1, or 5,6-dione-1,10-phenantroline, 2) on the surface of hexaniobate nanoscrolls. After adsorption, the turnover number for CO production (TONCO) in DMF/TEOA of 1 was increased from 9 to 58, which is 20% higher than that observed on TiO2, being among the highest reported values for a Re­(I)-based photocatalyst under visible light irradiation without any sensitizer. The complex 2 is inactive in solution under visible-light irradiation, but it has a TONCO of 35 when immobilized on hexaniobate nanoscrolls. Transient absorption spectroscopy studies reveal that the slow back-electron transfer and the higher reducing power of the hexaniobate conduction-band electrons play a major role for the photocatalytic process. The results provide new insights concerning the role of the metal oxide substrate on Re­(I)-based molecular systems for CO2 reduction.

Recent Advances in Niobium-Based Materials for Photocatalytic Solar Fuel Production

“…It is well known that, while metals and semiconductors usually exhibit great stability, but poor selectivity for CO 2 reduction, enzymes and metal complexes can selectively convert CO 2 into CO, but they lack long-term stability. Therefore, Faustino et al eValuated the role of hexaniobate nanoscrolls (K x H (4−x) Nb 6 O 17 ) as suitable substrates for the immobilization of two kinds of Re(I)-based molecular catalysts (namely I and II) for CO 2 photoreduction [104]. Hexaniobate nanoscrolls were obtained Funding: This research was funded by Doutorado CAPES/DAAD/CNPQ (15/2017) grant number 88887.161403/2017-00.…”

The role of substituted pyridine Schiff bases as ancillary ligands in the optical properties of a new series of fac-rhenium(i) tricarbonyl complexes: a theoretical view

“…Complexes based on a Re(I) tricarbonyl core with a dinitrogenated ligand (N,N such as 1,10-phenanthroline or 2,2 0 -bipyridine derivatives) in the equatorial position, and halogen or pyridine derivatives as ancillary ligands (X), have been extensively used for diverse applications, including solar cells, 1,2 catalysis, [3][4][5][6][7][8] and more recently, biological applications, [9][10][11][12][13][14][15][16][17] including staining of bacteria, yeasts (walled cells), and proteins separated by SDS-PAGE. 18,19 Photophysical attributes of fac-[Re(I)(CO) 3 (N,N)X] n complexes (where n is 0 or 1+) can be modulated by combining the (N,N) and X ligands.…”

Inorganic Photochemistry and Solar Energy Harvesting: Current Developments and Challenges to Solar Fuel Production

“…Moreover, its scrolled lamellar morphology can favor the electron mobility. After adsorption, the TON CO in DMF/TEOA of the complex fac-[Re(Cl)(CO) 3 (dcbH 2 )], dcbH 2 =4,4′-dicarboxylic acid-2,2′ -bipyridine was increased from 9 to 58, which is 20% higher than that observed on TiO 2 , being among the highest reported values for Re(I)-based photocatalysts under visible light irradiation without any sensitizer [207]. A summary of the reported photoactivities of immobilized Re(I) catalysts is shown in Table 2.…”