TY - JOUR
T1 - A single site catalyst supported in mesoporous UiO-66 for catalytic conversion of carbon dioxide to formate
AU - Gumbo, Maureen
AU - Ocansey, Edward
AU - Makhubela, Banothile C.E.
AU - Amombo Noa, Francoise M.
AU - Öhrström, Lars
AU - Mudraj, Obieda S.
AU - Mehlana, Gift
N1 - Publisher Copyright:
© 2024 The Royal Society of Chemistry.
PY - 2024/1/5
Y1 - 2024/1/5
N2 - Carbon dioxide utilisation strategies are of paramount importance, yielding various products such as methanol and formate. Formate is an excellent hydrogen carrier in fuel cells, making it a highly exploitable chemical on the hydrogen energy storage front. Formate has an energy content that is at least five times greater than that of commercially available lithium-ion batteries. Herein, we have prepared mesoporous metal-organic frameworks (MOFs) (m-UiO-66 and m-UiO-66-NH2), using a Zr-based secondary building unit (SBU) and terephthalate linkers. The MOFs were used to support the half-sandwich (tetrazolylpyridyl)iridium(iii) complex to make single-site catalyst (Ir(iii)@m-UiO-66 and Ir(iii)@m-UiO-66-NH2) for CO2 conversion to formate. Both Ir(iii)@m-UiO-66 and Ir(iii)@m-UiO-66-NH2 exhibited improved activity for CO2 hydrogenation to formate in a heterogeneous system. Ir(iii)@m-UiO-66-NH2 and Ir(iii)@m-UiO-66 had turnover numbers of 3313 and 3076 TON, respectively, under optimized conditions. X-ray photoelectron spectroscopy (XPS) showed possible interaction of the complex with the MOF as evidenced by a downfield shift in the binding energies of the Ir 4f electronic environment. The catalysts showed post-catalysis stability, as confirmed by PXRD, FTIR, and XPS. The Ir 4f binding energies of the materials after catalysis showed an up-field shift confirming the presence of Ir-H species which are the active species for catalysis.
AB - Carbon dioxide utilisation strategies are of paramount importance, yielding various products such as methanol and formate. Formate is an excellent hydrogen carrier in fuel cells, making it a highly exploitable chemical on the hydrogen energy storage front. Formate has an energy content that is at least five times greater than that of commercially available lithium-ion batteries. Herein, we have prepared mesoporous metal-organic frameworks (MOFs) (m-UiO-66 and m-UiO-66-NH2), using a Zr-based secondary building unit (SBU) and terephthalate linkers. The MOFs were used to support the half-sandwich (tetrazolylpyridyl)iridium(iii) complex to make single-site catalyst (Ir(iii)@m-UiO-66 and Ir(iii)@m-UiO-66-NH2) for CO2 conversion to formate. Both Ir(iii)@m-UiO-66 and Ir(iii)@m-UiO-66-NH2 exhibited improved activity for CO2 hydrogenation to formate in a heterogeneous system. Ir(iii)@m-UiO-66-NH2 and Ir(iii)@m-UiO-66 had turnover numbers of 3313 and 3076 TON, respectively, under optimized conditions. X-ray photoelectron spectroscopy (XPS) showed possible interaction of the complex with the MOF as evidenced by a downfield shift in the binding energies of the Ir 4f electronic environment. The catalysts showed post-catalysis stability, as confirmed by PXRD, FTIR, and XPS. The Ir 4f binding energies of the materials after catalysis showed an up-field shift confirming the presence of Ir-H species which are the active species for catalysis.
UR - http://www.scopus.com/inward/record.url?scp=85182362281&partnerID=8YFLogxK
U2 - 10.1039/d3se01465g
DO - 10.1039/d3se01465g
M3 - Article
AN - SCOPUS:85182362281
SN - 2398-4902
VL - 8
SP - 777
EP - 788
JO - Sustainable Energy and Fuels
JF - Sustainable Energy and Fuels
IS - 4
ER -
