Hydrophilic polypyrrole and g-C3N4 co-decorated ZnO nanorod arrays for stable and efficient photoelectrochemical water splitting

It is of practical significance to manufacture high-performance and durable semiconductor heterojunctions for photoelectrochemical (PEC) water splitting. Herein, hydrophilic polypyrrole and graphitic carbon nitride (g-C3N4) co-decorated ZnO nanorod arrays were synthesized as a photoanode by facile spin-coating and plasma-treatment methods. On the one hand, g-C3N4 nanosheets are modified on ZnO nanorod arrays to broaden the light-absorption range and suppress the recombination of photogenerated charges. On the other hand, the polypyrrole coating layer inhibits the dissolution and corrosion of ZnO nanorods and constructs a p-n heterojunction with ZnO to further promote the separation and transfer of photogenerated charge carriers. Furthermore, its hydrophilic surface provides a vast electrochemically active surface area for efficient charge/mass transfer. As a result, the as-prepared photoanode exhibits an enhanced PEC performance with a distinctly increased photocurrent and remarkably ameliorated stability in contrast to the ZnO photoanode. This research would provide an innovative perspective on the design of organic/inorganic semiconductor heterojunctions with excellent performance and stability for PEC water-splitting systems.

Automated summary

This study synthesized hydrophilic polypyrrole and graphitic carbon nitride decorated zinc oxide nanorod arrays as a photoanode, which exhibited enhanced performance and stability for photoelectrochemical water splitting. The modified g-C3N4 nanosheets broadened the light absorption range and suppressed the recombination of photogenerated charges, while the polypyrrole coating layer inhibited the dissolution and corrosion of zinc oxide nanorods and facilitated the separation and transfer of photogenerated charge carriers. The hydrophilic surface of the photoanode provided a large electrochemically active surface area for efficient charge/mass transfer.