Charge Relays via Dual Carbon-Actions on Nanostructured BiVO4 for High Performance Photoelectrochemical Water Splitting

Photoelectrochemical water splitting based on nanostructured bismuth vanadate (BiVO4) can be a promising strategy to produce low-cost and green H-2 to replace fossil fuels and realize carbon neutrality. Herein, a simple chemical way to realize in situ carbon doping into BiVO4 crystalline structure is designed and obtained carbon-doped BiVO4, namely C-BiVO4, can improve the electronic conductivity of BiVO4. In addition, the introduction of the synthesized carbon quantum dots (CQDs) as a co-catalyst, immobilizes CQDs onto the C-BiVO4 nanosheet and acquires the optimized C-BiVO4/CQDs heterogeneous structure, which not only boosts light absorption, but also enhances the separation and transfer of the photo-generated charges. Stemming from the dual carbon actions, the as-prepared C-BiVO4/CQDs photoanode exhibits an excellent photocurrent density of 4.83 mA cm(-2) at 1.23 V versus the RHE without the use of any hole scavengers. To assure the practical application of the sensitive photocatalyst, a polyaniline layer is electroplated onto the C-BiVO4/CQDs catalyst as a conducting, electroactive, and protective layer to sustain a remarkable long-term photocurrent density of 2.75 mA cm(-2) for 9 hours. This work suggests that the proposed low-cost, environmentally friendly dual carbon actions can modify photocatalyst and achieve green production of H-2.

Automated summary

Carbon doping and introduction of carbon quantum dots can improve the electronic conductivity and light absorption capability of BiVO4, thus enhancing the separation and transfer of photo-generated charges. Electroplating a polyaniline layer onto the catalyst can sustain a stable photocurrent density for a long time.