Enhanced photoinduced stability and photocatalytic activity of AgBr photocatalyst by surface modification of Fe(III) cocatalyst

• Fe(III) cluster was demonstrated to be a new and effective cocatalyst in Fe(III)/AgBr photocatalyst.
• The photoinduced stability of AgBr can be significantly enhanced by Fe(III) cocatalyst.
• The photocatalytic activity of AgBr photocatalyst can be greatly improved by the Fe(III) cocatalyst.
• A possible photocatalytic mechanism of Fe(III)/AgBr was proposed.

Recently, AgBr material was demonstrated to be a new and efficient visible-light photocatalyst for the decomposition of various organic compounds. Owing to its excellent photosensitive properties, however, AgBr phase is unavoidably decomposed into metallic Ag under visible-light irradiation, resulting in an obvious destroy of its surface structure. In this study, Fe(III) cocatalyst was grafted on the surface of AgBr particles to form Fe(III)/AgBr photocatalysts by an impregnation method and their photocatalytic performance was evaluated by the photocatalytic decolorization of methyl orange solution under visible-light irradiation. It was found that the Fe(III) cluster could act as a new and effective cocatalyst not only to improve the photocatalytic activity of AgBr photocatalyst, but also remarkably enhance the photoinduced stability of photosensitive AgBr. After surface coating by Fe(III) cocatalyst (8.2 at.%), the photocatalytic activity of AgBr photocatalyst can be greatly improved by a factor of 73% even after five cycles of photocatalytic reactions. Simultaneously, the decomposed amount of AgBr can be significantly deduced from 8.8 at.% to 2.9 at.% by the surface loading of Fe(III) cocatalyst. On the basis of the experimental results, an possible mechanism for the enhanced photocatalytic activity and photoinduced stability of AgBr by Fe(III) cocatalyst was proposed. Compared with the well-known noble metal cocatalysts (e.g., Pt, Au, Ag), the present abundant and cheap Fe(III) cocatalyst can be regarded as one of the ideal cocatalyst for the smart design and development of high-performance photocatalytic materials in various potential applications.

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