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Abstract Strontium‐substituted lanthanum cobaltite (La 0.8 Sr 0.2 CoO 3 ) matrix‐stabilized Co 0 /Co II catalytic sites were prepared, which present tunable C−O and C−C hydrogenolysis activity for the vapor‐phase upgrading of oxygenated arenes. Co II sites associated with oxygen vacancies were favored at low temperatures and performed selective C−O hydrogenolysis, in which Sr‐substitution facilitated oxygen vacancy formation, leading to approximately 10 times higher reactivity compared to undoped LaCoO 3 . Co 0 sites were favored at high temperatures and performed extensive C−C bond hydrogenolysis, generating a wide range of alkanes. The lower reaction order with P (1.1±0.1) for C−C hydrogenolysis than for C−O hydrogenolysis (2.0±0.1) led to a high selectivity towards C−C hydrogenolysis at low P . The Co 3 O 4 surfaces featured a narrower temperature window for obtaining the respective optimal Co II and Co 0 pairs compared to analogous perovskite surfaces; whereas, the perovskite matrix stabilizes these pairs for selective C−O and C−C hydrogenolysis. This stabilization effect offers an additional handle to control reactivity in oxide catalysts.
Shetty et al. (Fri,) studied this question.