Using Molecular Design to Control the Performance of Hydrogen-Producing Polymer-Brush-Modified Photocathodes.

Attachment of difluoroborylcobaloxime catalysts to a polymer-brush-modified GaP semiconductor allows improved hydrogen production levels and photoelectrochemical performance under aqueous acidic conditions (pH = 4.5) as compared to the performance of electrodes without catalyst treatment. The catalytic assembly used in this work incorporates a boron difluoride (BF2) capping group on the glyoximate ligand of the catalyst, a synthetic modification previously used to enhance the stability of nonsurface-attached complexes toward acid hydrolysis and to shift the cobalt reduction potentials of the complex to less negative, and thus technologically more relevant, values.

Hybrid photocathodes for solar fuel production: coupling molecular fuel-production catalysts with solid-state light harvesting and conversion technologies.

Artificial photosynthesis is described as the great scientific and moral challenge of our time. We imagine a future where a significant portion of our energy is supplied by such technologies. However, many scientific, engineering and policy challenges must be addressed for this realization.

Energetics and efficiency analysis of a cobaloxime-modified semiconductor under simulated air mass 1.5 illumination.

We report on the energetics and efficiency of a p-type (100) gallium phosphide (GaP) semiconductor functionalized with molecular hydrogen production catalysts via polymer grafting. The catalysts belong to the cobaloxime class of compounds that have recently shown promise in electrocatalysis and solar-to-fuel applications. Attachment of the complex to a semiconductor surface allows direct photoelectrochemical (PEC) measurements of performance.

The effect of axial ligand on the oxidation of syringyl alcohol by Co(salen) adducts.

Experimental work on the oxidation of the lignin model, syringyl alcohol, using oxygen and a Co(salen) catalyst has revealed variations in yield with different imidazole-based axial ligands. A reasonable linear relationship was found between product yield and pKa of the axial ligand. The current work, using density functional calculations, examined geometric, electronic, and energetic parameters to determine if additional quantitative relationships can be identified and used in subsequent catalyst design.