Facile synthesis, spectroscopy and electrochemical activity of two substituted iron phthalocyanines as oxygen reduction catalysts in an acidic environment

Fe-phthalocyanine derived highly conjugated 2D covalent organic framework as superior electrocatalyst for oxygen reduction reaction

Although porphyry systems like metallo-phthalocynine are recognized as promising molecular models for electrocatalytic oxygen reduction reaction (ORR), their poor durability and methanol tolerance are still challenges and need improvement before being considered for practical applications. Herein, we successfully designed and constructed a Fe-phthalocyanine-derived highly conjugated 2D covalent organic framework (2D FePc-COF), using octa-amino-Fe-phthalocyanine (OA-FePc) and cyclohexanone as precursors. The prepared 2D FePc-COF was characterized via multiple analytic techniques. The electrochemical studies indicated that prepared 2D FePc-COF was far more superior to OA-FePc and 20% Pt/C, displaying anodic shift of 100 and 50 mV (vs RHE) in formal potential, respectively. Moreover, this catalyst also demonstrated excellent methanol tolerance and durability (over 10,000 CV cycles). Theoretical investigations revealed that due to extended conjugation and elimination of electron donating groups (-NH2), the shifting of dz2-orbital (Fe) energy took nearer to π*-orbital (O2), allowing optimum coupling of both the orbitals, thereby enhancing 4e- ORR. This work demonstrates the art of molecular design, aiming at improving catalytic activity of macrocyclic molecular systems towards ORR.

Tuning the Covering on Gold Surfaces by Grafting Amino-Aryl Films Functionalized with Fe(II) Phthalocyanine: Performance on the Electrocatalysis of Oxygen Reduction

Current selective modification methods, coupled with functionalization through organic or inorganic molecules, are crucial for designing and constructing custom-made molecular materials that act as electroactive interfaces. A versatile method for derivatizing surfaces is through an aryl diazonium salt reduction reaction (DSRR). A prominent feature of this strategy is that it can be carried out on various materials. Using the DSRR, we modified gold surface electrodes with 4-aminebenzene from 4-nitrobenzenediazonium tetrafluoroborate (NBTF), regulating the deposited mass of the aryl film to achieve covering control on the electrode surface. We got different degrees of covering: monolayer, intermediate, and multilayer. Afterwards, the ArNO₂ end groups were electrochemically reduced to ArNH₂ and functionalized with Fe(II)-Phthalocyanine to study the catalytic performance for the oxygen reduction reaction (ORR). The thickness of the electrode covering determines its response in front of ORR. Interestingly, the experimental results showed that an intermediate covering film presents a better electrocatalytic response for ORR, driving the reaction by a four-electron pathway.

Nature-inspired electrocatalysts and devices for energy conversion

A NICE approach for the design of nature-inspired electrocatalysts and electrochemical devices for energy conversion.

Oxygen reduction reaction at MWCNT-modified nanoscale iron(ii) tetrasulfophthalocyanine: remarkable performance over platinum and tolerance toward methanol in alkaline medium

A novel nanoscale iron(ii) tetrasulfophthalocyanine complex catalyzes oxygen reduction reaction in alkaline medium more efficiently than the expensive state-of-the-art Pt catalyst.

High Performance Fe- and N- Doped Carbon Catalyst with Graphene Structure for Oxygen Reduction

Proton exchange membrane fuel cells are promising candidates for a clean and efficient energy conversion in the future, the development of carbon based inexpensive non-precious metal ORR catalyst has becoming one of the most attractive topics in fuel cell field. Herein we report a Fe- and N- doped carbon catalyst Fe-PANI/C-Mela with graphene structure and the surface area up to 702 m² g⁻¹. In 0.1 M HClO₄ electrolyte, the ORR onset potential for the catalyst is high up to 0.98 V, and the half-wave potential is only 60 mV less than that of the Pt/C catalyst (Loadings: 51 μg Pt cm⁻²). The catalyst shows high stability after 10,000 cyclic voltammetry cycles. A membrane electrode assembly made with the catalyst as a cathode is tested in a H₂-air single cell, the maximum power density reached ~0.33 W cm² at 0.47 V.

Iron phthalocyanine and nitrogen-doped graphene composite as a novel non-precious catalyst for the oxygen reduction reaction

We develop a facile method for the synthesis of an iron phthalocyanine (FePc) and nitrogen-doped graphene (NG) composite as a novel and efficient non-precious catalyst in the oxygen reduction reaction (ORR). The resulting product exhibits superior ORR catalytic activity, excellent tolerance to methanol crossover, and comparable stability to commercial Pt/C, which leads to the invention of a new non-precious catalyst for ORR in fuel cells.

Iodine doping of substituted μ-carbido iron diphthalocyanines

Hemi and amphi-substituted μ-carbido iron diphthalocyanine having general formula (t- bu ) 4PcFe-C-FePc and (t- bu ) 4PcFe-C-FePc (t- bu )4 have been oxidized with I2. The oxidized compounds have been characterized and their physicochemical properties have been studied; the results obtained lead to assign them the formula [(t- Bu ) 4PcFe-C-FePc ] (I5)0.66 and [[(t- Bu ) 4PcFe ]2 C ]] (I5)0.66 respectively. The conduction properties, related to the role played by the pushing groups inserted in the peripheral macrocycles, are discussed. Moreover, an effective purification method for improving the yield and purity of iron tetra-tert-butyl phthalocyanine is described, the difficulty being able to obtain this precursor with a high purity grade.

MALDI-TOFMS analysis of coordination and organometallic complexes: a nic(h)e area to work in

A mini-review of the characterisation of metal-containing compounds by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOFMS) is presented. Organometallic and coordination compounds have many varied applications, most notably in industrial catalytic processes and also in the electronics and healthcare sectors. In general, the compounds discussed, be they small or large molecules, have a high percentage metal content, rather than simply containing 'a metal atom'. A brief history of the field is given, but the main scope over the last 5 years is covered in some detail. How MALDI-TOFMS compliments electrospray for metal-containing compounds is highlighted. Perspectives on recent advances, such as solvent-free and air/moisture-sensitive sample preparation, and potential future challenges and developments, such as nanomaterials and metallodrug/metallometabolite imaging, are given.