Nanostructured polyoxometalate-modified SnO2 photoanode with improved photoelectrochemical performance

• It is first proof that POMs can improve the photoelectrochemical performance of SnO2.
• The role of PMo12 in SnO2 was revealed by surface photovoltage (SPV) spectroscopy.
• The PMo12/SnO2 films displayed the enhanced catalytic activity for methanol.

SnO2 has attracted considerable attention due to its excellent photoelectrochemical properties. However, its light-to-electricity conversion in photoelectrochemical devices is still inferior because of the high electron–hole recombination rate. Polyoxometalates (POMs) act as an efficient electron acceptor, which could capture the photogenerated electrons from conduction band of semiconductors and thus retard the electron–hole recombination. Here we study for the first time the effect of polyoxometalate electron acceptor on photoelectrochemical performance of SnO2, and demonstrate that the photocurrent and power conversion efficiency of the SnO2/POMs composite photoanode are markedly enhanced in comparison with that of the pristine SnO2 photoanode. The enhanced photovoltaic performance is attributed to the occurrence of photogenerated electron transfer from SnO2 to POMs; this decreases electron–hole recombination in SnO2. Furthermore, the SnO2/POM photoanode also showed significant photoelectrooxidation activity for methanol, which provides a further support for the functional mechanism of POMs in SnO2. This study presents a new insight into improving the light-to-electricity conversion efficiency of SnO2 by combination with POMs.