Two-dimensional g-C(3)N(4): an ideal platform for examining facet selectivity of metal co-catalysts in photocatalysis.

Two-dimensional g-C3N4 nanosheets with few-layer thickness, ensuring equivalent charge migrations to various Pd facets, provide an ideal model system for reliably examining the facet selectivity of Pd co-catalysts. It reveals that reduction of CO2 can occur better on Pd{111} facets while H2O prefers to generate H2 on Pd{100}.