Sonochemical Synthesis of Large Two-Dimensional Bi2O2CO3 Nanosheets for Hydrogen Evolution in Photocatalytic Water Splitting

Laterally large (approximate to 3 mu m), atomically thin 2D Bi2O2CO3 nanosheets (2D bismuth oxycarbonate, 2D bismutite) are fabricated via sonochemically assisted, template-free synthesis. Keys to the synthesis of the freestanding, laterally large 2D Bi2O2CO3 nanosheets from bulk Bi powder are choice of suspension medium, controlled reaction temperatures, and several hours processing time. Lateral sizes of 2D Bi2O2CO3 can be controlled between mu m-sized nanosheets and tens of nm sized nanoflakes solely based on the choice of suspension medium. The here introduced 2D Bi2O2CO3 nano-sheets/-flakes are then hybridized by a simple mix-and-match approach with TiO2 nanoparticles for testing in suspension-type photocatalytic hydrogen production via water splitting. This introduces the 2D Bi2O2CO3 as a prospective noble-metalfree catalyst component with TiO2 for photocatalytic hydrogen evolution, beyond Bi2O2CO3's current use as photocatalyst for organic pollutant degradation. These results enrich the fabrication toolbox of emerging 2D pnictogen oxycarbonates toward large 2D nanosheets and demonstrate the potential of 2D Bi2O2CO3 as a catalyst component for hydrogen evolution in photocatalytic water splitting.