Aqueous miscible organic solvent treated NiTi layered double hydroxide De-NOx photocatalysts

Abstract

New efficient photocatalysts are required to remediate polluted urban atmospheres. We prepared a series of highly dispersed aqueous miscible organic (AMO) solvent treated NiTi layered double hydroxide (NixTi-AMO-LDHs (x = 2,3)) and studied their performance in the photocatalytic abatement of NOx gases. These photocatalysts can be prepared by a simple and scalable coprecipitation method at room temperature. NixTi-AMO-LDHs (x = 2,3) have been prepared with specific N2 BET surface areas and pore volumes up to to 492 m2g–1 and 1.37 cm3 g–1 respectively. Under sunlight simulation, the De-NOx performance of the conventional LDH and P25 (TiO2) benchmarks were surpassed by 40% and 17% respectively by the NixTi-AMO-LDHs. The NixTi-AMO-LDHs photocatalyst also exhibited outstanding reusability and unusually low release of the toxic NO2. The selectivity for the De-NOx process was investigated by in situ DRIFT measurements, the high surface area and pore volume was observed to play a significant role on the adsorption of the NO2 and N2O4 intermediates. The 2D character of the AMO-LDHs contributed to an enhancement in the production of radical species under illumination and reduction charge carrier recombination.