Fused Hybrid Linkers for Metal–Organic Framework-Derived Bifunctional Oxygen Electrocatalysts

Abstract

Preparation of electrocatalysts often relies on the use of multiple starting materials, with examples arising from a single precursor being less common. We have surveyed a series of heterobivalent scaffolds to identify an iron/benzimidazole-based metal–organic framework as a uniform starting material. By merging the catechol and imidazole units together, we get a direct entry into a highly efficient bifunctional oxygen electrocatalyst, which alleviates the need for dopants and modifying conditions. We demonstrate that by fine-tuning the chemical nature of an organic linker, one is able to modulate the electrochemical properties of a single precursor-derived electrocatalyst material.

Multi-purpose heterogeneous catalyst material from an amorphous cobalt metal–organic framework

“…30 Typically, Co-N-C catalysts are used for reduction reactions (nitroarenes, 31,32 N-heterocycles, 33 and hydrocarbons 34 ), reductive aminations 35 and alkylations, 36,37 while the oxidative esterification of benzyl alcohols were done under dioxygen. [38][39][40] Overall, the cobalt materials outperformed the three previously reported related Fe-N-C systems (TAL-1-900, TAL-6-900, TAL-7-900), 22,23 and importantly, they sustained their activity over a larger number of cycles (Fig. 2A and B; Tables S6 and S7, ESI †).…”

“…During the pyrolysis, however, MOFs undergo drastic molecular rearrangements; hence, amorphous MOFs can be used as the precursors. 20,21 To this end, we recently assessed iron-based catalysts derived from polycrystalline metal-organic framework precursors (TAL-1-900, TAL-6-900, TAL-7-900), 22,23 which were based on carbon-rich 24 organic linkers. Even the slightest variations around the benzimidazole core have led to alterations in the performance of the materials as bifunctional oxygen electrocatalysts 22 and in heterogeneous catalysis.…”

“…20,21 To this end, we recently assessed iron-based catalysts derived from polycrystalline metal-organic framework precursors (TAL-1-900, TAL-6-900, TAL-7-900), 22,23 which were based on carbon-rich 24 organic linkers. Even the slightest variations around the benzimidazole core have led to alterations in the performance of the materials as bifunctional oxygen electrocatalysts 22 and in heterogeneous catalysis. 23 Herein, we report a unique amorphous cobalt-based MOF-derived multifunctional material, which acts as an efficient trifunctional electrocatalyst 25,26 and as a robust heterogeneous catalyst.…”

Synthesis and Performance of MOF-Based Non-Noble Metal Catalysts for the Oxygen Reduction Reaction in Proton-Exchange Membrane Fuel Cells: A Review

“…A recent work has described a new family of carbon-rich benzimidazole-based MOF precursors equipped with various functional groups to modulate their electronic and ligating properties [ 113 ] and prepared from FeCl 3 and 5,6-disubstituted 1 H -benzo[ d ]imidazoles (substituent = OH, COOH, or OCH 3 ) as ligands. The best MOF was prepared in the case of substituent = OH and pyrolyzed at 900 °C to yield a material (denoted as TAL-1-900) comprising dense ≈15-nm α-Fe/Fe 3 C@C nanocrystals embedded into onion-like carbon shells.…”

Bimetal Phthalocyanine‐Modified Carbon Nanotube‐Based Bifunctional Catalysts for Zinc‐Air Batteries

“…[11] Accordingly, many efforts have been made to develop highly active non-precious bifunctional electrocatalysts for ORR or OER, or for both oxygeninvolving reactions (e. g. suitable electrocatalyst for both, ORR and OER). [13][14][15][16][17][18][19][20][21][22][23][24] Among numerous non-precious metal catalysts, it has been established that the transition metal and nitrogen co-doped nanocarbon (MÀ NÀ C) catalysts are promising candidates for ORR due to the synergetic effects of metal and nitrogen in addition to the graphitic and porous structure of carbon. [25][26][27][28][29][30] For OER, transition metal oxides are good replacement for state-of-the-art IrO 2 and RuO 2 catalysts.…”