Smart Electrodes for electrocatalytic water splitting

Efficient production of H2 from water through electrolysis represents a promising method towards a clean and renewable energy carrier. However, the cathodic hydrogen evolution reaction (HER) and the anodic oxygen evolution reaction (OER) of water electrolysis both require catalysts that can substantially lower the overpotentials. Therefore, developing noble-metal free electrocatalysts is a highly relevant and timely issue in a wide range of energy conversion processes to improve the conversion/utilization efficiency. Our group has been actively working on nanoarray materials directly on conductive substrates as electrodes for both supercapacitor, batteries as well as electrocatalyst.

In this talk, I will first introduce the RF plasma as a highly effective technique for conversion reaction and surface functionalization of electrode materials for HER and OER. The plasma treatment not only generates hierarchical nanostructured surface (thus higher surface areas), but also induces N-doping as well as hydrophilicity. This is a fast and NH₃-free strategy to synthesize metal nitrides for various applications such as catalysts, supercapacitors and batteries.

Second, I will discuss the formation of a series of ultrafine transition metal-based nanoparticles embedded in N-doped carbon layers on carbon cloth for both HER and OER catalysts. The synthesis was realized by employing an in-situ reduction of metal precursor and an interesting metal-assisted carbon etching process. We demonstrate Ni-Mo and Ni-Fe embedded in N-doped carbon as bi-functional electrocatalysts for water splitting. Finally, I may present the realization of pure carbon arrays as bi-functional electrocatalysts. The N-doped and mesoporous carbon nanoflakes array are realized by converting reaction.

References

• Ouyang, B.; Zhang, Y. Q.; Wang, Y.;, Zhang, Z.; Fan, H. J. and Rawat, R. S., Mater. Chem. A, 2016, 4, 17801-17808
• Yongqi Zhang, Guichong Jia, Huanwen Wang, Bo Ouyang, Rajdeep Singh Rawat, Hong Jin Fan^*, Materials Chemistry Frontiers, Advanced article
• Zhang, Y. Q.; Ouyang, B; Xu, J.; Jia, G. C.; Chen, S.; Rawat, R. S.; and Fan, H.J., Chem. Int. Ed. 2016, 128, 8812–8816.
• Zhang, Y. Q.; Ouyang, B; Xu, J; Chen, S.; Rawat, R. S.; and Fan, H.J. Energy Mater. 2016, 6, 1600221.