Efficient Photocatalytic Hydrogen Peroxide Production over TiO2 Passivated by SnO2

Guifu Zuo,Yi Du,Xianguang Meng,Zhaoliang Guo,Shanshan Liu,Weishu Hou,Tao Wang,Peixiao Zong,Bingdong Li,Liang Wang,Fan Yang,Songtao Zhang,Vellaisamy A L Roy

doi:10.3390/catal9070623

Abstract

Photocatalysis provides an attractive strategy for synthesizing H2O2 at ambient condition. However, the photocatalytic synthesis of H2O2 is still limited due to the inefficiency of photocatalysts and decomposition of H2O2 during formation. Here, we report SnO2-TiO2 heterojunction photocatalysts for synthesizing H2O2 directly in aqueous solution. The SnO2 passivation suppresses the complexation and decomposition of H2O2 on TiO2. In addition, loading of Au cocatalyst on SnO2-TiO2 heterojunction further improves the production of H2O2. The in situ electron spin resonance study revealed that the formation of H2O2 is a stepwise single electron oxygen reduction reaction (ORR) for Au and SnO2 modified TiO2 photocatalysts. We demonstrate that it is feasible to enhance H2O2 formation and suppress H2O2 decomposition by surface passivation of the H2O2-decomposition-sensitive photocatalysts.

Highlights

Hydrogen peroxide (H2 O2 ) is a clean oxidant [1] that has wide applications in environmental purification and organic synthesis [2]
Au-modified SnO2 -TiO2 was successfully prepared for enhanced photocatalytic activity for H2 O2 production
H2 O2 formed through a stepwise single electron reduction process over Au and/or SnO2 modified TiO2 via the formation of HO2

Summary

Introduction

Hydrogen peroxide (H2 O2 ) is a clean oxidant [1] that has wide applications in environmental purification and organic synthesis [2]. H2 O2 is industrially produced by the multi-step anthraquinone method, which consumes a lot of energy and organic solvent [3]. As an alternative to the anthraquinone method, direct photocatalytic synthesis of H2 O2 has attracted widespread attention due to its mild reaction conditions, such as normal temperature and pressure under light irradiation. An important feature of photocatalytic H2 O2 formation is that it is accompanied by a decomposition process. TiO2 is a widely used photocatalyst for synthesizing H2 O2

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