An appealing strategy for ensuring environmental benefits of the photocatalytic NO oxidation reaction is to convert NO into NO 3 - instead of NO 2 , yet the selectivity of products remains challenging. Here, such a scenario could be realized by tailoring the exposure of Lewis acid sites on the surface of ZrO 2 , aiming to precisely regulate the ROS evolution process for the selective oxidation of NO into NO 3 - . As evidenced by highly combined experimental characterizations and density functional theory (DFT) simulations, Lewis acid sites serving as electron acceptors could induce itinerant electron redistribution, charge-carrier transfer, and further oxidation of •O 2 - , which promotes the oriented formation of 1 O 2 . As a result, monoclinic ZrO 2 with more Lewis acid sites exhibited an outstanding NO conversion efficiency (56.33%) and extremely low NO 2 selectivity (5.04%). The ROS-based reaction process and promotion mechanism of photocatalytic performance have been revealed on the basis of ESR analysis, ROS-quenching experiments, and in situ ROS-quenching DRIFTS. This work could provide a critical view toward oriented ROS formation and advance a unique mechanism of selective NO oxidation into NO 3 - .