Photon-Resilient CsPbBr3 Nanocrystals Achieved Through Cation-Ligand Synergistic Surface Engineering for Cocatalyst-Free High-Performance CO2 Photoreduction.

Lead halide perovskite nanocrystals (PNCs) combine strong light harvesting with favorable excited-state properties for solar-fuel synthesis, yet their application in CO2 photoreduction is limited by rapid photoinduced surface degradation. Here, we overcome this limitation through cooperative cation-ligand engineering of CsPbBr3 PNCs by integrating surface-associated Zn2 + with short-chain isophthalic acid (IPhA). This dual surface coordination reinforces halide bonding, stabilizes undercoordinated Pb sites, suppresses defect propagation, prolongs carrier lifetime, increases carrier density, and reduces charge-transfer resistance. Mechanistic investigations, including operando Raman spectroscopy and CO-stripping voltammetry, reveal sustained surface-bound intermediates and favorable CO adsorption-desorption behavior during CO2 reduction. Consequently, the Zn-IPhA engineered PNCs sustain continuous CO and CH4 evolution for 10 h under simulated solar irradiation and retain high activity over three consecutive 10 h cycles with only marginal performance loss. The engineered PNCs deliver cocatalyst-free CO evolution rates of ∼55 and ∼64 µmol g-1 h-1 together with CH4 evolution rates of ∼20 and ∼26 µmol g-1 h-1 under white-light (1 Sun) and UV irradiation, respectively, representing the highest reported productivities among 3D PNC photocatalysts and surpassing many cocatalyst-integrated systems. These findings establish cooperative surface coordination engineering as a general strategy for developing photon-resilient perovskite photocatalysts for solar-fuel generation.