Novel Reactive Anodisation as General Synthesis of Composite Oxide Nanorods/Nanotubes Array - Towards Highly Efficient Solar Water Splitting

Project: Research

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Etching anodisation has been one of the most convenient routes of preparing aligned 1-D nanostructures. These simple oxide nanorods/nanotubes find many breakthrough green applications ranging from dye-sensitised solar cells, photocatalytic carbon dioxide reduction, solar water splitting, noxious gas sensing to environmental remediation. The advantages of 1D array are profound, from streamlining the diffusion path of electrons in photovoltaic applications to the tuning of reactant residence time in photocatalytic applications. Despite its widespread interests, the technique is limited by large to the preparation of single component oxides from its parental metal foils.Hence,a novel concept termed as Reactive Anodisation (RA) is proposed here for the first time. Whilst retaining the ability to yield aligned nanorods/nanotubes array as in conventional etching anodisation, the RA incorporates the formation of complex oxides (2 metal components or more) through in situ electrochemical reaction between the parental foil and arbitrary choice of secondary dissolved metal cations. In other words, the facile RA technique allows the implementation of aligned complex oxide structures, such as metal titanates, niobates, tantalates, molybdates and vanadates. This opens up anunderexplored area of the general synthesis of complex oxide nanorods/nanotubesand more importantly theirrich chemistries and applications.In this proposal, the novel RA technique will be applied to the synthesis of water splitting photocatalysts (for solar hydrogen generation from water), which is dominated by a variety of complex oxide materials. Although RA technique can be conveniently extended to thesynthesis of composite oxides for many other applications, here the designing of water splitting photocatalysts is an interesting avenue in view of its foremost importance as a clean hydrogen generation technology. The creation of composite oxide photocatalysts in vertically aligned nanorods/nanotubes array representsmagnitudes increase in specific surface areascompared to the standard prepared solid-state reaction. More importantly, the 1-D arrays allow moreefficient charge transportespecially when applied in a photoelectrochemical configuration which readily separates the hydrogen evolution from that of oxygen.Success of the proposed research will lead to theefficient generation of hydrogen purely from solar and seawater/wastewater. The latter further leads to the simultaneous hydrogen generation and wastewater remediation. Towards the final stage, an outdoor solarpowered water splitting system will be constructed from the assembly of RA synthesised photoelectrodes module. Such demonstration system will serve as precursortowards commercialization effortas well assecuring energy future.


Project number9041649
Grant typeGRF
Effective start/end date1/01/1218/12/15