Unveiling the Dynamic Evolution of Single-Atom Co Sites in Covalent Triazine Frameworks for Enhanced H₂O₂ Photosynthesis

Abstract

Unraveling the structural evolution and mechanism of active sites in single-atom catalysts (SACs) during H2O2 production under operational conditions remains challenging due to the transient and elusive nature of the underlying reaction processes. Herein, we employ operando X-ray absorption spectroscopy and ab initio molecular dynamics simulations to unveil the dynamic reconstruction behavior of the Co single atom-loaded covalent triazine framework (CoSA/Py-CTF) during photocatalytic H2O2 production. The unique Py-CTF substrate provides reasonable structural flexibility to the single atom Co site. Under light irradiation and O2 adsorption, single Co atoms are dynamically released from the Py-CTF substrate and then form transient atom-pairs with neighboring Co atoms, serving as the authentic active site. The dynamic shuttling of Co subnanometer domains between single-atoms and atom-pairs facilitates the transition of the O2 adsorption configurations from Pauling type to Yeager type, resulting in a record photocatalytic H2O2 yield (2898.3 μmol·h–1·g–1). These findings provide insightful observations into the dynamic photochemical behavior of SACs and present an fresh paradigm for the design of intelligent “adaptive catalysts”.

Enhanced electrochemical CO2-to-ethylene conversion through second-shell coordination on a Cu single-atom catalyst

“…To evaluate the catalytic performance of Cu–C 3 N 4 -HA in CO 2 RR applications, a series of experiments were conducted in a flow cell reactor to evaluate its catalytic activity and selectivity. 55–60 LSV measurements were performed on C 3 N 4 , Cu–C 3 N 4 , and Cu–C 3 N 4 -HA to determine the optimal potential of the CO 2 RR. As depicted in Fig.…”