ePrints

Improving the photocatalytic reduction of CO₂ to CO through immobilization of a molecular Re catalyst on TiO₂

Lookup NU author(s): Dr Anna Reynal Verdu

Downloads

• Published version [.pdf]

Licence

This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).

Abstract

The photocatalytic activity of phosphonated Re complexes, [Re(2,2’-bipyridine-4,4’-bisphosphonic acid)(CO)₃(L)] (ReP) with L = 3-picoline, or L = bromide, immobilized on TiO₂ nanoparticles is reported. The heterogenized Re catalyst on the semiconductor, ReP-TiO₂ hybrid, displays an improvement in CO₂ reduction photocatalysis. A high turnover number (TON) of 48 mol CO (mol Re)^–1 was observed in DMF with the electron donor triethanolamine at l > 420 nm, which compares favourably to previously reported homogeneous systems and is the highest TON observed with a CO₂ reducing Re catalyst under visible light in the absence of an additional molecular dye. Photocatalytic CO₂ reduction could even be observed with ReP-TiO₂ using wavelengths l > 495 nm. Infrared and X-ray photoelectron spectroscopies confirmed that an intact ReP catalyst is present on the TiO₂ surface before and during catalysis. Transient absorption spectroscopy suggests that the high activity upon heterogenization is due to an increase in the lifetime of the immobilized anionic Re intermediate (t_50% > 1 s for ReP-TiO₂ compared with t_50% = 60 ms for ReP in solution) and immobilization might also reduce the formation of inactive Re dimers. This study demonstrates that the activity of a homogenous photocatalyst can be improved through immobilization on a metal oxide surface by favorably modifying its photochemical kinetics.

Publication metadata

Author(s): Windle CD, Pastor E, Reynal A, Whitwood AC, Vaynzof Y, Durrant JR, Perutz RN, Reisner E

Publication type: Article

Publication status: Published

Journal: Chemistry - A European Journal

Year: 2015

Volume: 21

Issue: 9

Pages: 3746-3754

Print publication date: 23/02/2015

Online publication date: 29/01/2015

Acceptance date: 15/12/2014

Date deposited: 15/12/2014

ISSN (print): 0947-6539

ISSN (electronic): 1521-3765

Publisher: Wiley - VCH Verlag GmbH & Co. KGaA

URL: http://dx.doi.org/10.1002/chem.201405041

DOI: 10.1002/chem.201405041

Altmetrics

Funding

Share