New insights into the effect of polyvinyl alcohol on Co3O4 spinel oxide catalyst for N2O decomposition

Polyvinyl alcohol (PVA)-assisted precipitation method offered surface modification Co3O4 spinel oxides, showing outstanding N2O catalytic performance. Induction of PVA restrained crystal grain growth and gave rise to the emergence of high specific surface area. Simultaneously, PVA superhydrophobicity and reducibility generated more Co2+ ions during the preparation process, which were regarded as active sites in N2O decomposition. [Display omitted] •Co3O4 prepared by PVA-assisted precipitation method exhibited outstanding catalytic N2O decomposition performance;•Co2+ vital role as active centers was revealed by characterization and DFT calculation;•PVA superhydrophobicity and reducibility regulated Co3O4 surface atom coordination states and generated more Co2+ ions. Polyvinyl alcohol (PVA)-assisted precipitation method offered surface modification Co3O4 spinel oxides which were applied to catalytic N2O decomposition. PVA was added in the preparation process and endowed catalysts with changes in surface metal ions valance state properties, i.e. Co2+ ions which served as active centers. Co3O4 adding PVA (Co3O4-P) showed superior performance for catalytic N2O decomposition with a high gas hourly space velocity of 400,000 h−1. Co2+ ion quantities were positively correlated to catalytic performance which was inseparable from PVA superhydrophobicity and reducibility during the preparation process. Moreover, density functional theory (DFT) calculation revealed N2O preferable adsorption on Co2+ sites whether near oxygen vacancies or not, which indirectly affirmed the reason Co3O4-P with superior catalytic N2O decomposition property. Our research gave more evidence to N2O decomposition active sites from atom-scale for Co3O4 spinel oxides and provided a novel pathway for high-performance catalyst preparation.