A sequential doping strategy for architecturally controlled BiVO₄ photoanodes with synergistic co-doping enabled by...

Area of Science:

• Materials Science
• Photocatalysis
• Renewable Energy

Background:

• Nanoporous bismuth vanadate (BiVO4) photoanodes fabricated via bismuth oxyiodide (BiOI) templating offer high-quality films.
• Conventional doping is incompatible with BiOI-templated BiVO4, leading to poor charge transport and limited performance in pristine BiVO4.

Purpose of the Study:

• To introduce a novel doping strategy for BiVO4 photoanodes.
• To overcome the limitations of bulk charge transport in BiOI-templated BiVO4.
• To enhance the performance of BiVO4 photoanodes for solar fuel generation.

Main Methods:

• Developed a controlled, quantitative, precursor-state, sequential doping strategy.
• Co-doped BiVO4 with barium (Ba) and niobium (Nb).
• Decorated the optimized Nb/Ba co-doped BiVO4 photoanode with a nickel iron oxide (NiFeO_x) co-catalyst.

Main Results:

• Achieved over 95% charge separation efficiency.
• The optimized Nb/Ba co-doped BiVO4 photoanode demonstrated a photocurrent density of 6.2 mA cm^-2 at 1.23 V vs. RHE.
• A 4-fold increase in photocurrent density compared to the undoped counterpart was observed.

Conclusions:

• The novel doping strategy effectively resolves bulk electronic limitations in BiOI-templated BiVO4.
• The synergetic co-doping of Nb and Ba significantly enhances photoanode performance.
• This work sets a new standard for designing high-performance solar fuel devices using rational design principles.