3D Urchin-like Hierarchical Black TiO2 Hollow Nanospheres: A Highly Active and Stable Electrocatalyst for Water Oxidation in Alkaline and Neutral Media

Clean production of renewable fuels is a great challenge of our scientific community. Iridium complexes have demonstrated a superior catalytic activity in the water oxidation (WO) reaction, which is a crucial step in water splitting process. Herein we have used a defective zirconium MOF with UiO-66 structure as support of a highly active Ir complex based on EDTA with formula [Ir(HEDTA)Cl]Na. The defects are induced by the partial substitution of tereftalic acid with smaller formiate groups. Anchoring of the complex occurs through a post-synthetic exchange of formiate anions, coordinated at the zirconium clusters of the MOF, with the free carboxylate group of the [Ir(HEDTA)Cl]-complex. The modified material was tested as heterogenous catalyst for the WO reaction by using Cerium Ammonium Nitrate as sacrificial agent. Although TOF and TON values are comparable to those of other iridium heterogenized catalysts, the MOF exhibits iridium leaching not limited at the first catalytic run, as usually observed, suggesting a lack of stability of the hybrid system under strong oxidative conditions.

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Two‐Phase Colloidal Synthesis of Amorphous Iron‐Doped Manganese Phosphate Hollow Nanospheres for Efficient Water Oxidation

Advanced Sustainable Systems ◽

10.1002/adsu.202000128 ◽

2020 ◽

Vol 4 (11) ◽

pp. 2000128 ◽

Cited By ~ 1

Author(s):

Yan Liu ◽

Jifu Zhang ◽

Wei Wang ◽

Lixin Cao ◽

Bohua Dong

Keyword(s):

Water Oxidation ◽

Colloidal Synthesis ◽

Hollow Nanospheres ◽

Two Phase ◽

Amorphous Iron ◽

Manganese Phosphate ◽

Iron Doped

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Post Synthetic Defect Engineering of UiO-66 Metal–Organic Framework with An Iridium(III)-HEDTA Complex and Application in Water Oxidation Catalysis

Inorganics ◽

10.3390/inorganics7100123 ◽

2019 ◽

Vol 7 (10) ◽

pp. 123 ◽

Cited By ~ 1

Author(s):

Giordano Gatto ◽

Alceo Macchioni ◽

Roberto Bondi ◽

Fabio Marmottini ◽

Ferdinando Costantino

Keyword(s):

Water Oxidation ◽

Metal Organic Framework ◽

Oxidation Catalysis ◽

Partial Substitution ◽

Iridium Complexes ◽

Cerium Ammonium Nitrate ◽

Highly Active ◽

Water Oxidation Catalysis ◽

Metal Organic ◽

Organic Framework

Clean production of renewable fuels is a great challenge of our scientific community. Iridium complexes have demonstrated a superior catalytic activity in the water oxidation (WO) reaction, which is a crucial step in water splitting process. Herein, we have used a defective zirconium metal–organic framework (MOF) with UiO-66 structure as support of a highly active Ir complex based on EDTA with the formula [Ir(HEDTA)Cl]Na. The defects are induced by the partial substitution of terephthalic acid with smaller formate groups. Anchoring of the complex occurs through a post-synthetic exchange of formate anions, coordinated at the zirconium clusters of the MOF, with the free carboxylate group of the [Ir(HEDTA)Cl]− complex. The modified material was tested as a heterogeneous catalyst for the WO reaction by using cerium ammonium nitrate (CAN) as the sacrificial agent. Although turnover frequency (TOF) and turnover number (TON) values are comparable to those of other iridium heterogenized catalysts, the MOF exhibits iridium leaching not limited at the first catalytic run, as usually observed, suggesting a lack of stability of the hybrid system under strong oxidative conditions.

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