Abstract
The photocathodes are essential in photoelectrochemical systems for harvesting solar energy as green fuels. However, the light-absorbing p-type semiconductor in them usually suffers from carrier recombination issues. An effective strategy to address it is fabricating the p-n heterojunction to create an interfacial electric field. However, plenty of deposition process of the n-type layer for this purpose requires either sophisticated instruments or subsequent treatments, which may damage the vulnerable p-type structure. Herein, we report a mild approach for a ready-to-use n-type layer with full functionality. Structural analyses proved the successful coating of a uniform titania layer (up to 40 nm) over Cu2O without damaging its structure. Owing to the high Ti3+ content, the layer possesses excellent charge transport ability and requires no additional annealing. The heterojunction effectively facilitates the carrier separation and positively shifts the photocurrent onset potential for 0.2 V. The Mott–Schottky plot and the impedance study reveal an enhanced carrier collection with reduced charge transfer resistances. Such a nano-heterojunction can be further loaded with the hydrogen evolution catalyst, which almost doubles the photocurrent with an extended lifetime than that of the pristine Cu2O nanoarray. This approach puts forward a potentially scalable and efficient choice for fabricating photoelectrochemical devices.
Highlights
Oxide photocathodes have attracted great attention for the photoelectrocatalytic production of hydrogen fuels by solar water splitting (Li et al, 2020)
We successfully developed a new electrochemical route to realize the coating of functional titania over Cu2O nanowire arrays (NWAs)
The bottom Cu2O NWAs were prepared by a two-step method using our previously reported anodization process for uniformed Cu(OH)2 NWAs, followed by a spontaneous thermal conversion to Cu2O in an inert atmosphere (Cao et al, 2020)
Summary
Oxide photocathodes have attracted great attention for the photoelectrocatalytic production of hydrogen fuels by solar water splitting (Li et al, 2020). By incorporating the merit of all measures, the Cu2O NWA-based photocathodes were manifested as the landmark featuring their excellent photoelectrochemical (PEC) efficiency and stability (Huang et al, 2013) These three-dimensional architectures drastically increased the difficulty of the fabrication processes. Titanium oxide appears to be one of the essential components in the coating It does prevent corrosions of Cu2O from the electrolyte solution and rectifies the flow of photogenerated carriers (Li et al, 2015). Titanium oxide layers from oxidizing Ti(III) over other nanostructures effectively formed various junctions, exhibiting outstanding photochemical or PEC properties (Toe et al, 2019) None of these electrochemical processes is applicable to Cu2O nanostructures. These features of the photocathodes present a new promising route of using a rationally designed electrochemical process to fabricate uniform and functioning heterostructure under mild conditions
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
