Photocatalytic NH3 versus H2 evolution over g-C3N4/CsxWO3: O2 and methanol tipping the scale

Cs x WO 3 nanorods can be used to sensitize the single layer g-C 3 N 4 , where full spectrum light harvesting excited electrons to drive the photocatalytic reduction of N 2 into NH 3 . Under UV light, both water splitting and solar ammonia synthesis reaction exhibit high activity. However, selectivity towards ammonia over hydrogen is realized under NIR irradiation. With the control of methanol, O 2 can directly decide the NH 3 or H 2 evolution on photocatalyst. The origin is the strong capture of O 2 with the electrons from the photocatalyst under light irradiation to yield the oxygen active species, which transfer electrons subsequently with help of methanol to generate NH 3 . However, H 2 production will be suppressed by O 2 . And with its sacrifice, methanol preserves the produced NH 3 from oxidation. The O 2 -sacrificial agent mediated NH 3 evolution reaction found here provides insights in the promotion role of them in other catalysis.