Photocatalytic reduction of nitrogen to ammonia on diamond thin films grown on metallic substrates

TitlePhotocatalytic reduction of nitrogen to ammonia on diamond thin films grown on metallic substrates
Publication TypeJournal Article
Year of Publication2016
AuthorsBandy, JA, Zhu, D, Hamers, RJ
JournalDiamond and Related Materials
Pagination -
Date Published01/2016
ISBN Number0925-9635
KeywordsCatalytic processes, Diamond film, Electrochemical, Interface electronic properties, Plasma CVD

Recent studies have demonstrated that boron-doped diamond can act as a solid-state source of electrons in water when illuminated with above-bandgap light. Excitation of electrons to diamond's conduction band leads to facile emission of electrons into water; the resulting solvated electrons are potent reducing agents able to initiate many chemical reactions such as the reduction of N2 to NH3 and the reduction of CO2 to CO. Here, we report investigations of the photocatalytic activity of diamond thin films grown on Mo, Ni, and Ti substrates. Our results show that in each case, there is a maximum in the photocatalytic activity that occurs just when the diamond coalesces into a contiguous film, then decreasing as the film becomes thicker. These results suggest that electron emission arises in part from excitation of electrons in the metal substrate, followed by injection into the conduction band of the diamond film. More detailed studies on films grown on niobium show that at the open-circuit potential the films have a downward bend-bending of ~ 0.3 V, which is favorable for barrier-free electron emission. Our result suggests that metal–diamond heterostructures may provide a scalable approach to achieving difficult photocatalytic reactions.

Short TitleDiamond and Related Materials