Rationally designed/assembled hybrid BiVO4-based photoanode for enhanced photoelectrochemical performance

BiVO4, an attractive photoanode material, has been extensively researched in recent years. However, the photocurrent density of BiVO4-based photoanode is still much less than its theoretical value of 7.5 mA/cm(2) at 1.23 V-RHE. The performance of BiVO4 is generally considered to be hindered by its photocorrosion and sluggish kinetics of oxygen evolution reaction. Herein, a hybrid BiVO4-based photoanode is constructed by modifying nanoporous BiVO4 with a Fe-phenolic layer (FTA) and a case of molecular catalyst 1 ([CO4(H2O)(4)(HPMIDA)(2)(PMIDA)(2)](6-)). The FTA layer with abundant phenolic groups can protect BiVO4 from photocorrosion. With assembling catalyst 1 on FTA interlayer, an eye-catching photocurrent density of 5.5 mA/cm(2) is obtained at 1.23 V-RHE, which is much higher than that of bare BiVO4 (1.5 mA/cm(2)). The stability of 1/FTA/BiVO4 photoanode is investigated, maintaining 93% of the photocurrent density at 0.7 V-RHE after 3 h stability test. Systematic studies reveal that the excellent PEC activity comes from the protection of BiVO4 and the enhancement of surface reaction efficiency. These results support the concept of designing and assembling hybrid photoanode containing heterogeneous cocatalyst and molecular catalyst for efficient solar-fuel conversion.