Direct evidence of the efficient hole collection process of the CoOx cocatalyst for photocatalytic reactions: a surface photovoltage study†
The true effect of a cocatalyst on photocatalytic reactions is one of the major issues to resolve in photocatalysis research. Herein, the efficient hole collection role of the CoOx cocatalyst grown on TiO2-nanotubes has been directly proved by surface photovoltage (SPV) spectroscopy. Transient SPV measurements provide evidence that the CoOx cocatalyst could significantly prolong the life-time of photogenerated holes. Furthermore, it is proposed that the hole collection effect can be attributed to the work function difference between the TiO2 and CoOx interface. These findings demonstrate that the development of a cocatalyst with a suitable work function can be a general strategy for photoconversion applications.