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Development of a solar water splitting device requires design of a low-cost, efficient, and non-noble metal compound as alternative to noble metals. For the first time, we showed that CoSe2 can function as co-catalyst in phototoelectrochemical hydrogen production. We designed a heterostructure of p-Si and marcasite-type CoSe2 for solar-driven hydrogen production. CoSe2 successively coupled with p-Si can act as a superior photocathode in the solar-driven water splitting reaction. Photocurrents up to 9 mA cm−2 were achieved at 0 V vs. reversible hydrogen electrode. Electrochemical impedance spectroscopy showed that the high photocurrents can be attributed to low charge transfer resistance between the Si and CoSe2 interfaces and that between the CoSe2 and electrolyte interfaces. Our results suggest that this CoSe2 is a promising alternative co-catalyst for hydrogen evolution. [ABSTRACT FROM AUTHOR]

Blaue, grüne und gelbe Leuchtmaterialien werden vom Sr1−xY0.98+xCe0.02Si4N7−xCx ‐ System (x=0→1) gebildet. Die Schwelle für die thermische Lumineszenzlöschung sinkt mit zunehmendem x. Ursache ist ein dominanter Nachbarkationeneffekt, der dazu führt, dass beim Ersatz von Sr2+ durch Y3+ die Kovalenz der Ce ‐ N ‐ Bindung gemindert wird. Die grüne Emission tritt bei einer kationensegregierten Nanostruktur von SrYSi4N7 ‐ und Y2Si4N6C ‐ Domänen in Proben mit x=0.2 – 0.6 auf. [ABSTRACT FROM AUTHOR]