Quantum-sized silver, silver chloride and silver sulfide clusters

Thin AgCl layers photocatalytically oxidize water to O-2 under appropriate conditions, The photoactivity of AgCl extends from the UV into the visible light region in a process known as self-sensitization, which is due to the formation of silver during the photoreaction. This silver can be almost qua ntitatively reoxidized electrochemically, making it feasible that a thin Ag Cl layer deposited on a conducting substrate can be used as a photoanode fo r water splitting if coupled with an appropriate photocathode. The silver c hloride/silver cluster phase boundary plays a decisive role in the photocat alytic silver chloride electrode system. We have therefore studied this int erphase by means of quantum chemical calculations from which we report firs t results, specifically for the (Ag)(115)(AgCl)(192) composite. Clusters of semiconducting materials are interesting considering their application as a photocathode in such a device. In this context, we also report the synthe sis and properties of luminescent quantum-Sized silver sulfide clusters in the cavities of zeolite A. The color of the silver sulfide zeolite A compos ites ranges from colorless (low loading) to yellow-green (medium loading) t o brown (high loading). A low silver sulfide content is characterized by a blue-green luminescence and distinct absorption bands, while samples with m edium or high silver sulfide content show an orange or red colored emission and a continuous absorption.