Ni(OH)2 clusters decorated NiTiO3 Z-scheme heterojunctions with strong O2 activation and robust interfacial built-in electric field for efficient NO photo-oxidation

Photocatalytic oxidation offers a viable method for removing low-concentration NO from the atmosphere. However, poor oxygen adsorption-activation capacity and high re-combination rate of electrons and holes limit the photocatalytic NO oxidation activity. To over-come these problems, Ni(OH) 2 clusters decorated NiTiO 3 Z-scheme heterojunctions are constructed by a precipitation method. The tight interfacial contacts and built-in electric field between the (0   0   2) crystal facet of Ni(OH) 2 and (0   1   2) crystal facet of NiTiO 3 promote a Z-scheme charge transfer mechanism. This Z-scheme mechanism will enhance the charge-transfer driving force and result in high separation efficiency of the charges, thus leading to an enhanced photocatalytic performance. Importantly, introducing Ni(OH) 2 is considered a promising strategy to enhance the adsorption ability of the O 2 , NO and NO 2 . This might help to increase O 2 activation efficiency and speed up NO deep oxidation, leading to high NO removal efficiency and low NO 2 selectivity. Benefiting from the above excellent properties, the photocatalytic NO oxidation efficiency of Ni(OH) 2 /NiTiO 3 composites is enhanced and the formation of more toxic NO 2 is inhibited compared with that of NiTiO 3 . This work offers a promising and effective route to design efficient NiTiO 3 -based photocatalysts in the application of environmental remediation.