Isolated Co‐Ti‐Y Trimetallic Synergistic Catalysis Based on Apparent Anti‐Electronegative Polarization

Abstract

Rational design of multimetallic synergistic catalysis is a grand challenge in the field of green catalysis because synergistic mechanisms are poorly understood. Here, by exploiting a unique apparent anti-electronegativity polarization in cobalt-titanium-yttrium trimetallic synergy, a unified methodology is demonstrated to activate oxygen and nitrogen. The new trimetallic synergistic catalyst achieves direct solvent-free aerobic oxidation of cyclohexane to adipic acid and direct nitrogen oxidation of acetonitrile to guanidine. The delocalization of d-orbitals and activation of inner electrons are the linchpins of catalytic performance, contributing to 90.87% selectivity for ketone-alcohol oil and adipic-acid and 89.30% selectivity for guanidine, respectively. The experiments and calculations demonstrate that the prodigious electrophilicity of the yttrium site overcomes the homeostasis of valence shell structures in the isolated cobalt and titanium sites. The valence electrons of this synergistic system become enriched with anti-electronegative polarization and concomitant high charge transfer efficiency. In response to urging sustainable chemistry, the results corroborate that the activation strategies and mechanisms of molecular oxygen and nitrogen can be moderated and unified when multimetallic synergy is considered.

Constructing Defective Co3V2O8 Hexagonal Prism for Solvent-free Selective Oxidation of Cyclohexane: Strategy of Ionic Liquid Mediation

“…The O 1s spectra of different CVO samples are shown in Figure c. The three distinct peaks at around 530.5, 532.2, and 533.3 eV were associated with lattice oxygen (O L ), OVs (O v ), and hydroxy species of surface-adsorbed water molecules (O γ ). , OVs can effectively activate molecular oxygen to form reactive oxygen species with upgraded oxygen mobility and reactivity, and further enhance the initiation of C–H bond and the transformation of intermediates. , Therefore, OV concentration is the crucial structural parameter to evaluate its catalytic activity of CVO materials in selective oxidation, which can be calculated based on the ratio of peak area (O v /(O L + O v + O γ ) and it was summarized in Table . The CVO-300 catalyst had the lowest surface OV concentration under low-temperature heat treatment, while the OV concentration was improved through increasing the calcination temperature as depicted in the CVO-700 catalyst.…”