Biaobiao Zhang

Highly Efficient Oxidation of Water by a Molecular Catalyst Immobilized on Carbon Nanotubes

A successful team: A molecular device based on multiwalled carbon nanotubes functionalized by a mononuclear ruthenium catalyst has been shown to split water electrochemically (see picture; ITO=indium tin oxide). The readily prepared electrode showed excellent electrocatalytic activity for the oxidation of water, a high current density, and a low overpotential, and constitutes one step forward in the design of artificial photosynthetic systems.

Towards A Solar Fuel Device: Light‐Driven Water Oxidation Catalyzed by a Supramolecular Assembly

Time to split: Supramolecular assemblies containing both photosensitizers and a ruthenium water-oxidation catalyst were prepared and characterized. The pictured assembly exhibits, for the first tim ...

Promoting the Activity of Catalysts for the Oxidation of Water with Bridged Dinuclear Ruthenium Complexes

Solar fuels: Dinuclear ruthenium catalysts prepared from two covalently bridged monomeric catalytic units show outstanding activities towards the oxidation of water with high turnover numbers up to 43 000 and turnover frequencies up to 40 s-1 (see picture). Direct comparison of the performance parameters indicates that the dimers are significantly more active as catalysts than the monomers.

Chemical and photochemical oxidation of organic substrates by ruthenium aqua complexes with water as an oxygen source

Two ruthenium aqua complexes were shown to be effective catalysts in chemical and photochemical oxidation of hydrocarbons. A remarkable activity (up to 90% yield and 100% selectivity) was performed in conversion of sulfide to sulfoxide by homogeneous photooxidation.

Visible Light-Driven Water Oxidation Promoted by Host–Guest Interaction between Photosensitizer and Catalyst with A High Quantum Efficiency

A highly active supramolecular system for visible light-driven water oxidation was developed with cyclodextrin-modified ruthenium complex as the photosensitizer, phenyl-modified ruthenium complexes as the catalysts, and sodium persulfate as the sacrificial electron acceptor. The catalysts were found to form 1:1 host-guest adducts with the photosensitizer. Stopped-flow measurement revealed the host-guest interaction is essential to facilitate the electron transfer from catalyst to sensitizer. As a result, a remarkable quantum efficiency of 84% was determined under visible light irradiation in neutral aqueous phosphate buffer. This value is nearly 1 order of magnitude higher than that of noninteraction system, indicating that the noncovalent incorporation of sensitizer and catalyst is an appealing approach for efficient conversion of solar energy into fuels.

Homogeneous oxidation of water by iron complexes with macrocyclic ligands.

The activity of eleven separated iron complexes and nine in situ-generated iron complexes towards catalytic water oxidation have been examined in aqueous solutions with Ce(NH4)2(NO3)6 as the oxidant. Two iron complexes bearing tridentate and tetradentate macrocyclic ligands were found to be novel water oxidation catalysts. The one with tetradentate ligand exhibited a promising activity with a turnover number of 65 for oxygen evolution.

In Situ Formation of Efficient Cobalt-Based Water Oxidation Catalysts from Co2+-Containing Tungstate and Molybdate Solutions

Replacing rare and expensive noble-metal catalysts with inexpensive and earth-abundant ones is of great importance to split water either electrochemically or photoelectrochemically. In this study, two amorphous cobalt oxide catalysts (Co-W film and Co-Mo film) with high activity for electrocatalytic water oxidation were prepared by fast, simple electrodeposition from aqueous solutions of Na2WO4 and Na2MoO4 containing Co(2+). In solutions of Na2WO4 and Na2MoO4, sustained anodic current densities up to 1.45 and 0.95 mA cm(-2) were obtained for Co-W film at 1.87 V versus a reversible hydrogen electrode (RHE) and Co-Mo film on fluorine-doped tin oxide (FTO) substrates at 1.85 V versus RHE. For the Co-W film, a much higher current density of 4.5 mA cm(-2) was acquired by using a stainless-steel mesh as the electrode substrate. Significantly, in long-term electrolysis for 13 h, the Co-W film exhibited improved stability in cobalt-free buffer solution in comparison with the previously reported Co-Pi film.