Tailoring charge transport in BaBiO3/NaTaO3 heterojunction interface for enhanced photocatalytic and photoelectrochemical H2 generation

Photoactive perovskites NaTaO3 and BaBiO3 were synthesized by the solid-state method. The resulting compounds were mixed by wet impregnation, adding BaBiO3 (BBO) onto the base material NaTaO3 (NTO) to obtain the compounds X-BBO/NTO (X = 5-30 wt.%). The sample 20-BBO/NTO presented the largest crystallites (135 nm). Since BaBiO3 presents narrower Eg value (approximate to 2 eV) than NaTaO3 (approximate to 4 eV), the addition of BBO to NTO promoted a better visible light harvesting. This feature can be explained by the formation of a heterojunction, which improves the photocatalytic activity by an abatement of the charge carrier recombination. Photoelectrochemical tests showed an improvement in the charge transfer resistance and enhanced photoelectrocatalytic activity for the 20-BBO/NTO sample, over the other BBO concentrations and bare photocatalysts. An optimal amount of BaBiO3 (20 wt.%) increased the synergy of the n-type heterojunction by an enhancement in the charge transfer processes to perform the photoelectrocatalytic water splitting. 20-BBO/NTO sample showed the highest hydrogen production of 54 mu mol g(-1), which outstripped L4 times the photocatalytic hydrogen generation of the bare NaTaO3 semiconductor.