Dalton Transactions

Gupta, Gajendra; Gusmão, Filipe; Paul, Anup; Šljukić, Biljana; Santos, Diogo M. F.; Lee, Junseong; Guedes da Silva, M. Fátima C.; Pombeiro, Armando J. L.; Lee, Chang Yeon

doi: 10.1039/d3dt02421kpmid: 38059528

Oxygen evolution reaction (OER) electrocatalysts are frequently made from noble metal-based oxides like ruthenium/iridium oxides. However, because of their scarcity and high price, researchers are now focusing on creating innovative OER catalysts based on affordable transition metals that have improved electrical conductivity and accessibility to active sites. Metal–organic frameworks (MOFs), a unique class of inorganic materials with excellent physical and chemical properties, have witnessed significant progress in promising green energy systems. In this work, a novel mixed-ligand metal–organic framework [Co(μ-1κN,2κN′-BDP)(μ3-1κoo′,2κo′′2κo′′′-BTC)]n·nH2O (BDP = boron-dipyrromethene or BODIPY; BTC = benzene tricarboxylate) denoted as CoBDPMOF has been synthesized, and its composites with different carbon materials have been designed. Compared to the pristine MOF, the composites showed enhanced electrocatalytic activity toward the oxygen evolution reaction (OER) in alkaline media. In addition, the CoBDPMOF with activated carbon showed the highest OER performance with a low Tafel slope (82 mV dec−1) and the highest j600 (59.8 mA cm−2), outperforming noble metal IrO2, the OER benchmark electrocatalyst. This study presents new insights into the design and application of CoBDPMOF-based materials for energy conversion and suggests promising avenues for further research and development in electrocatalysis.

Li, Ting-Ya; Su, Shao-Dong; He, Yong; Wu, Xin-Tao; Sheng, Tian-Lu

doi: 10.1039/d3dt01861jpmid: 38226679

The goal of this study was to investigate how the electron-donating capability around the lower valent metal ion and the electron-accepting capability of the higher valent metal ion influence metal to metal charge transfer (MMCT) properties in mixed-valence complexes. A series of trinuclear ruthenium complexes represented as [Ru2(ap-4-Me)3(CH3COO)N0000000000000000000000000000000000000000000000000000111111111111111000000000000000000011111111111111100000000000000000001111111111111110000000000000000000000000000000000000000000000000000CRuCpMex(dppe)][PF6] (CpMex = polymethylcyclopentadienyl, x = 0, 1, and 5; and dppe = 1, 2-bis(diphenylphosphino)ethane, ap-4-Me = 2-anilino-4-methylpyridine) and their one-electron oxidized products were synthesized and fully characterized. The UV–vis-NIR spectra confirmed that as the electron donor character of the CpMex(dppe)RuCN fragment enhanced or the electron-accepting capability of the higher valent diruthenium cluster increased, the RuII → RuV2 or RuVI2 Ru2 MMCT bands shifted to lower energies, which was supported by TDDFT calculations.