Triangle Cl−Ag₁−Cl Sites for Superior Photocatalytic Molecular Oxygen Activation and NO Oxidation of BiOCl

Abstract

BiOCl photocatalysis shows great promise for molecular oxygen activation and NO oxidation, but its selective transformation of NO to immobilized nitrate without toxic NO2 emission is still a great challenge, because of uncontrollable reaction intermediates and pathways. In this study, we demonstrate that the introduction of triangle Cl‐Ag1‐Cl sites on a Cl‐terminated, (001) facet‐exposed BiOCl can selectively promote one‐electron activation of reactant molecular oxygen to intermediate superoxide radicals (•O2‒), and also shift the adsorption configuration of product NO3‒ from the weak monodentate binding mode to a strong bidentate mode to avoid unfavorable photolysis. By simultaneously tuning intermediates and products, the Cl‐Ag1‐Cl‐landen BiOCl achieved > 90% NO conversion to favorable NO3‒ of high selectivity (> 97%) in 10 min under visible light, with the undesired NO2 concentration below 20 ppb. Both the activity and the selectivity of Cl‐Ag1‐Cl sites surpass those of BiOCl surface sites (38% NO conversion, 67% NO3‒ selectivity) or control O‐Ag1‐O sites on a benchmark photocatalyst P25 (67% NO conversion and 87% NO3‒ selectivity). This study develops new single‐atom sites for the performance enhancement of semiconductor photocatalysts, and also provides a facile pathway to manipulate the reactive oxygen species production for efficient pollutant removal.

Dissecting the Photochemical Reactivity of Metal Ions during Atmospheric Nitrate Transformations on Photoactive Mineral Dust

“…During the reaction process, reactive oxygen species with strong oxidizing ability, such as superoxide radicals, produced on the surface of TiO 2 could promote the reoxidization of generated NO X to nitrates, resulting in decreased gas-phase product concentration. ,− An argon atmosphere was applied to the nitrate decomposition reaction to reduce the generation of reactive oxygen species and alleviate the oxidation of NOx (Figures d and S2). In the presence of Mg 2+ , higher concentrations of NO and NO 2 were observed, which could be attributable to the reduced reoxidation process of generated NO X .…”

Photocatalytic NOx removal and recovery: progress, challenges and future perspectives

“…1e and f ). 39 The NO x removal efficiency of Ag 1 /BiOCl reached up to 90%, with 97% selectivity for NO 3 − and minimal emission of NO 2 ( Fig. 1g–i ).…”

“…Among the redox products of NO x , NO 3 − is the dominant and accessible substance on the surface of the photocatalyst. 39,67 Significant quantities of NO 3 − are released into the environment through processes such as the combustion of fossil fuels and agricultural activities, driven by the progress of urbanization and industrialization. 115 The surface of the photocatalyst is the overlooked storage site for NO 3 − , where the generated nitrate could be easily removed from the catalyst and subsequently concentrated in liquid form.…”

Engineering the Coordination Environment of Ir Single Atoms with Surface Titanium Oxide Amorphization for Superior Chlorine Evolution Reaction

“…It is well known that the catalytic performances of SACs are strongly related to their coordination environment, demanding moderate metal–support interactions (MSIs) to optimize the absorption energy of reactants on metal atoms. ,− During the manufacturing procedure, the crystallinity of Ti-based electrodes is changed, which thus influences the coordination structure of single atoms and their activity. In order to elucidate the intrinsic structure–activity relationship of Ti-based single-atom electrodes, herein, we precisely manipulate the thermal annealing environment of Ir single atoms anchored on Ti foam.…”