Solar Fuel Generation By Semiconductor-Graphene Heterogeneous Photocatalysts

Semiconductors have been extensively used as photocatalysts and photoelectrodes for solar fuel generation. Currently single semiconducting material cannot suffer from low efficiency of conversion of solar energy to chemical energy. An alternative to overcome this barrier is to the development of hetero-structured photocatalysts.

This presentation shows that integration of semiconductors with graphene can significantly improve the photocatalytic activity. First, hematite (a-Fe₂O₃) nanocrystals have been deposited on the reduced graphene oxide (rGO) sheets to form the hematite/rGO heterogeneous photocatalyst, which shows much higher photocatalytic activity toward water oxidation.¹ The photocatalysis enhancement is due to the fact that facilitates the charge migration and reduces the charge recombination rate.

In addition, we have developed a heterogeneous photocatalyst based on the nanoscale p-n junction of p-type molybdenum disulfide/n-type nitrogen-doped reduced graphene oxide.² It is interesting that MoS₂ alone exhibits negligible photocatalytic activity. In contrast, the MoS₂/rGO p-n junction photocatalyst show significant photocatalytic activity toward hydrogen generation.

References

[1] F. Meng, J. Li, S. K. Cushing, J. Bright, M. Zhi, J. Rowley, Z. Hong, A. Manivannan, A. D. Bristow, N. Q. Wu, ACS Catalysis, 3 (2013), 746–751.

[2] F. Meng, J. Li, S. K. Cushing, M. Zhi, N. Q. Wu, J. Am. Chem. Soc., 135 (2013), 10286-10289

Acknowledgement:

The resource and facilities used were partially supported by NSF (EPS 1003907), the West Virginia University Research Corporation and the West Virginia EPSCoR Office. The use of WVU Shared Facility was appreciated.