Solar Fuel Generation by 2D Self-Assembled g-C3N4/BiVO4 Z-Scheme

Graphitic carbon nitride (g-CN) is a promising photocatalyst for solar fuel generation due to its medium band gap and facile synthesis from earth-abundant materials. However, low charge carrier mobility and high charge recombination have hampered the observed rate of H-2 evolution and CO2 reduction. Herein, an electrostatically self-assembled 2D Z-scheme heterojunction between g-CN and bismuth vanadate (BiVO4) is investigated with and without reduced graphene oxide (rGO) acting as an electron transfer mediator to speed charge carrier mobility and hamper charge recombination. Protonation of the g-CN surface allow for self-assembly between 2D sheets of g-CN, rGO, and BiVO4. The mass ratio between g-CN and BiVO4 is incrementally adjusted to optimize synergistic charge transportation effects versus shadowing effects of multicomponent photocatalysts. Further, a selectivity effect is observed across mass ratios of photocatalyst constituents, allowing tuning of photocatalyst yield.