Efficient Homogeneous Electrocatalytic Water Oxidation by a Manganese Cluster with an Overpotential of Only 74 mV

Abstract

Water electrolysis is among the simplest method for generating hydrogen as an alternative renewable fuel. A major challenge associated with this process is the development of cheap, simple, and environmentally benign catalysts that lead to a minimum overpotential for water oxidation. Inspired by the Mn4CaOx cluster that catalyzes water oxidation in photosystem II, described here is the synthesis and characterization of the manganese cluster [Mn12O12(O2CC6H2(OH)3)16(H2O)4] (Mn12TH) along with its electrocatalytic activity at pH 6. Electrochemical, spectroscopic, and electron microscopy studies show that Mn12TH is a homogeneous electrocatalyst for water oxidation and enables oxygen evolution with a reaction rate of 22 s−1, high Faradic efficiency (93 %), and an overpotential of only 74 mV, the lowest reported to date. Based on the electrochemical data, the organic ligands, which can be described as the second coordination sphere of the catalytic manganese core, play a key role in facilitating the oxidation process and accelerating the reaction.

Photoassisted Hydrothermal Synthesis of IrOx–TiO2 for Enhanced Water Oxidation

“…Recently, the widely explored methods for designing good OER electrocatalysts are focused on building more surface sites for water adsorption and dissociation, ,− which happens in the surface double electrode layer (DEL). To date, we have reported that the additional 3d empty electronic orbitals of tungsten enhance water adsorption, and the solid/solution interface resistance of the corresponding DEL is reduced, which then lowers the water oxidation overpotential .…”

Partially delocalized charge in crystalline Co–S–Se/NiOx nanocomposites for boosting electrocatalytic oxygen evolution

“…1D exhibited a broad peak between 30 and 40 degrees of the 2y value, which indicated the different diffraction peaks of Co 0.45 S 0.38 Se 0.17 compared with standard CoS 2 (PDF # 41-1471; a = b = c = 5.5376 Å; space group: Pa3), and the different diffraction peaks corresponding to the standard CoSe 2 (PDF # 09-0234; a = b = c = 5.8588 Å; space group: Pa3). 50,51 The binary CoSe 2 nanosheets nearly have the same diffraction peaks as the CoSe 2 cubic crystals.…”

Hexagonal Mo Bronze: Single Crystal Structures, Electrocatalytic Hydrogen Evolution, and Proton Conductivity

“…We have carried out the quantitative H 2 evolution experiment in a homemade electrochemical cell (three-electrode system) to measure the H 2 gas produced by compound 1 during the CPE experiment at a constant potential of −0.53 V versus RHE. We have thereby calculated the Faradaic efficiency of compound 1 for the HER, which was found to be 88.6%, as shown in Figures S15–16 and Section S5 (SI). , …”

“…We have thereby calculated the Faradaic efficiency of compound 1 for the HER, which was found to be 88.6%, as shown in Figures S15−16 and Section S5 (SI). 59,60 In order to understand the HER kinetics of compound {Mn 0.03 Na 0.01 }@[Mo 0.93 VI Mo 0.07 V O 3 ] (1), EIS studies were carried out. As shown in Figure S17 (SI), compound 1 shows a lower charge transfer resistance value (R ct = 82.72 Ω) as compared to the blank glassy carbon electrode (157.10 Ω), as estimated from the semicircles in the high-frequency range of the Nyquist plots.…”