Metal-Organic Cages for Ultrafast Photocatalytic Synthesis of Hydrogen Peroxide.

Abstract

In the realm of photocatalytic production, discrete metallo-organic cages have emerged as promising photocatalysts. However, their performance is often constrained by limited substrate accessibility and sluggish oxygen reduction reaction (ORR) kinetics. Herein, we designed and synthesized two novel nonnoble metallo-cages, S1 and S2, and evaluated their photocatalytic activities. Benefit from the high structural stability, low exciton binding energy (52.9 meV), ultrafast intramolecular electron transfer (49.50 ps), and prolonged excited-state lifetime (1, 970 ps), S2 exhibits efficient charge carrier separation. In addition, a bottom-up approach was employed to disperse S2 into ultrasmall nanoscale particles, which significantly enhanced substrate accessibility and the reaction kinetics. Furthermore, the addition of sodium oxalate not only optimizes charge carrier separation and utilization but also provides a kinetically favorable pathway for superoxide radical anion (·O2 -) generation, overcoming ORR kinetic bottlenecks. These synergistic effects culminate in a record production rate of 77, 401 µmol g-1h-1 and a solar-to-chemical conversion efficiency of 0.97%, outperforming most reported organic photocatalytic systems.