Immobilization of Prussian Blue Nanoparticles Onto Au-Modified ZnIn2S4 Photoanode for Efficient Photoelectrochemical Water Splitting

Graphical Au nanoparticles and PB-modified ZnIn 2 S 4 composite photoanode are successfully prepared on FTO substrates. The ZnIn 2 S 4 /Au/PB photoanode achieves a photocurrent density of 0.42 mA/cm 2 at 1.23 V RHE under light illumination alongside a high incident photon-to-electron conversion efficiency (IPCE) value of 24.6 %. ZnIn 2 S 4 has been regarded as a promising photoanode material for photoelectrochemical (PEC) water splitting. However, its severe charge recombination and low carrier transport efficiency limit practical applications in PEC water splitting. A novel ZnIn 2 S 4 /Au/PB photoanode was prepared by using the in-situ photodeposition of Au nanoparticles and electrodeposition of Prussian blue (PB) nanoparticles onto ZnIn 2 S 4 nanosheets. The photocurrent density of the prepared ternary photoanode reached 0.42 mA/cm 2 at 1.23 V RHE , which is 6 times higher than pure ZnIn 2 S 4 . The introduction of Au nanoparticles remarkably improved the efficiency of carrier transport and separation. Additionally, the application of PB onto ZnIn 2 S 4 resulted in an extended spectrum of light absorption. The incident photon-to-current efficiency (IPCE) value recorded was 24.6 % at 350 nm. This improvement can be attributed to the formation of a Z-type heterojunction.