Search

A facile synthesis for a photosensitizer-water oxidation catalyst (PS-WOC) dyad, which is connected through a polymeric platform, has been reported. The dyad assembly consists of a ruthenium-based chromophore and a cobalt-iron pentacyanoferrate coordination network as the water oxidation catalyst while poly(4-vinylpyridine) serves as the bridging group between two collaborating units. Photocatalytic experiments in the presence of an electron scavenger reveal that the dyad assembly maintains its activity for 6 h while the activity of a cobalt hexacyanoferrate and Ru(bpy)(3)(2+) couple decreases gradually and eventually decays after a 3 h catalytic experiment. Infrared and XPS studies performed on the post-catalytic powder sample confirm the stability of the dyad during the catalytic process.

Research on H2 production has recently been directed to the development of cost-efficient and robust heterogeneous catalysts for hydrogen evolution reaction (HER). Given the promising catalytic activities of several cobalt-based systems and the robustness of Prussian blue analogues in harsh catalytic processes including water oxidation, a Co-Co Prussian blue analogue was investigated as a HER catalyst for the first time. Co-Co Prussian Blue modified fluorine doped tin oxide (FTO) electrode demonstrated a significant HER activity with an onset overpotential of 257 mV, a Tafel slope of 80 mV dec−1, and a turnover frequency of 0.090 s−1 at an overpotential of 250 mV. Comparative XPS, Infrared, and XRD studies performed on pristine and post-catalytic electrodes confirm the stability of the catalyst. Acknowledgements This work was suppoerted by the Grants from The Science and Technology Council of Turkey, TUBITAK (Project No: 215Z249). E. U. thanks TUBITAK for support (Project No: 1929B011500059).

Although cobalt-based heterogeneous catalysts are the central focus in water oxidation research, interest in copper-based water oxidation catalysts has been growing thanks the great abundance of copper and its biological relevance. Several copper oxides have recently been reported to be active catalysts for water oxidation. In this study, a heterogeneous copper-based water oxidation catalyst that is not an oxide has been reported for the first time. Single-crystal XRD studies indicate that the compound is a one-dimensional coordination compound incorporating copper paddle-wheel units connected through phosphine dioxide ligands. The catalyst exhibits an onset potential of 372 mV at pH 10.2, whereas an overpotential of only 563 mV is required to produce a current density of 1 mA cm−2. In addition to cyclic voltammetric and chronoamperometric studies, an investigation into the effect of pH on the catalytic activity and the robustness of the catalyst using long-term bulk electrolysis (12 h) is presented.

A new microporous metal dicyanamide cluster, Co(hmt)(dca)(2) (hmt: hexamethylenetetramine, dca: dicyanamide), with accessible N-donor sites exhibits high CO2/N-2 selectivity, 83 at 295 K and 1 bar, for a mixture with a 15:85 CO2 to N-2 ratio. Adsorption studies show that the use of hmt and dca moieties as building blocks for solid adsorbents can enhance the CO2:surface interactions due to N atoms available inside the pores, which is confirmed by X-ray single crystal studies. (C) 2016 Elsevier Inc. All rights reserved.