As affordable electrocatalysts for oxygen reduction reactions (ORR) in metal-air batteries, nitrogen-carbon supported atomically dispersed single-atom transition-metal electrocatalysts are emerging. Accurately modulating the first-shell coordination of single-atom metal sites remains challenging, which impedes the elucidation of geometric/electronic structures for optimizing ORR catalysts. Aiming to tackle this challenge by rational design and constructing an asymmetric coordination model catalyst Co-B/N-C, herein we unravel that asymmetric B-coordination stimulates the generation of Co high spin state (t_2g5e_g2). By using X-ray absorption spectroscopy (XAS), we confirm Co active sites are atomically dispersed with a first-shell coordination of boron and nitrogen atom (Co-B₁N₃). Thus, the adsorption strength and electron transfer between the cobalt centers and the reactants/intermediates were boosted for optimal ORR capacity (E_1/2 = 0.87 V). Our work will provide valuable new perspectives on the strategic development of high-performance magnetic metal catalysts for ORR.

Hydrocracking catalysis is a controllable route to plastic waste upgrading. However, the mismatched acid site-driven C–C cleavage and C=C hydrogenation process on metal restrict the efficiency and selectivity in conventional metal/acid bi-functional catalyst. Herein, we introduce Al deficiency in Si-O(H)-Al structural units of Pt/zeolite socony mobil-5 (Pt/ZSM-5) through discharge driven reduction (DR) process to precisely control the ratio of metal to acid, achieving hydrocracking of low-density polyethylene (LDPE) waste at 270 °C with 87.7% conversion and liquid fuel (C₅-C₂₁) selectivity of 77.8%. Pair distribution function (PDF) and nuclear magnetic resonance (NMR) spectroscopy demonstrate the partial absent Al sites further resulting short-range local disorder Si-O(H)-Al. Upon pyridine infrared spectroscopy (Py-IR) and CO diffuse reflectance Fourier-transform infrared (CO DRIFT) analysis, the extraction of Al modulates Brønsted acid density of Pt/ZSM-5 with DR process (Pt/Z5_DR), improves the interaction between Pt and ZSM-5 support, enhances the cationic of Pt. The metal-acid balance and electron-deficient Pt favor the matching speed of light olefins hydrogenation and the cracking of macromolecule intermediates. Moreover, density functional theory (DFT) calculations identify the thermodynamic stability of Pt/Z5_DR and moderate adsorption capability towards light olefins. This work confirms the great potential of precisely controlled molar of metal to acid in metal/zeolite catalysts for LDPE upcycling, providing a viable path for dealing with PE plastic wastes.