The development of efficient water oxidation catalysts based on inexpensive and Earth-abundant materials is a prerequisite to enabling water splitting as a feasible source of alternative energy. In this work, we report the synthesis of ternary cobalt manganese phosphide nanoparticles from the solution-phase reaction of manganese and cobalt carbonyl complexes with trioctylphosphine. The CoMnP nanoparticles (ca. 5 nm in diameter) are nearly monodisperse and homogeneous in nature. These CoMnP nanoparticles are capable of catalyzing water oxidation at an overpotential of 0.33 V with a 96% Faradaic efficiency when deposited as an ink with carbon black and Nafion. A slight decrease in activity is observed after 500 cycles, which is ascribed to the etching of P into solution, as well as the oxidation of the surface of the nanoparticles. Manganese-based ternary phosphides represent a promising new system to explore for water oxidation catalysis.

The lack of efficient and stable oxygen evolution reaction (OER) catalysts comprising inexpensive Earth-abundant materials limits the viability of water splitting as a clean and renewable source of energy. In this work, we report the synthesis of homogeneous ternary Fe2–x Mn x P nanorods with control of Mn incorporation (0 ≤ x ≤ 0.9) from the solution-phase reaction of manganese and iron carbonyl complexes with trioctylphosphine. The OER activity of Fe2–x Mn x P nanorods dramatically increases with the incorporation of Mn (overpotential as low as 0.44 V at 10 mA/cm2 for x = 0.9), and the overpotential can be further decreased (by nearly 0.1 V) by postdeposition annealing. The enhanced OER activity and stability, along with the abundance and availability of Fe and Mn, make bimetallic manganese–iron phosphides a promising class of materials for more cost-effective and efficient water oxidation catalysis.

Langmuir-Blodgett films of metallosurfactants were used in Au|molecule|Au devices to investigate the mechanisms of current rectification.

No abstract

A series of cobalt complexes with pentadentate pyridine-rich ligands is studied. An initial Co(II) amine complex 1 is prone to aerial oxidation yielding a Co(III) imine complex 2 that is further converted into an amide complex 4 in presence of adventitious water. Introduction of an N-methyl protecting group to the ligand inhibits this oxidation and gives rise to the Co(II) species 5. Both the Co(III) 4 and Co(II) 5 show electrocatalytic H2 generation in weakly acidic media as well as in water. Mechanisms of catalysis seem to involve the protonation of a Co(II)-H species generated in situ.