Proportions of Mn and Co in BMxC1-x perovskite altered catalytic performance and ecological safety: Insights into algal metabolic response

Perovskites have been widely used in catalysis because of high activity and low cost. Although the catalytic efficiency of perovskites could be strengthened by adjusting the type and proportion of B-site element, the relationship between their performance and ecological risks is unknown. In this study, three Ba-based perovskites with different proportions of Mn and Co at the B-site (BMCs) were synthesized to compare their catalytic efficiency in activation of peroxymonosulfate (PMS). Moreover, their toxicity to freshwater alga Chlorella vulgaris were evaluated. Increasing the B-site Mn/Co ratio populated the amount of the oxygen vacancies (OVs). BMC with the B-site Mn/Co ratio of 1: 1 exhibited the highest catalytic activity in PMS activation for degradation of aqueous 4-chlorophenol. All three perovskites induced the algal growth inhibition in a dose-dependent manner, followed by the order of BM_0.8C_0.2 > BM_0.2C_0.8 ≈ BM_0.5C_0.5. Microscopy observations collectively found that the B-site regulated perovskites could destroy cell structures. Notably, metabolite homeostasis in algal cells was disturbed by three BMCs, uridine monophosphate and pentacosanoic acid could be potential biomarkers for evaluating their ecotoxicity. The highest catalytic activity with relatively low toxicity of BMCs with the Mn/Co ratio of 1:1 at B-site, probably because of Mn release rather than OVs. This research expanded our perception of the ecotoxicity of new-type perovskites in aquatic environment.