High-Performance Overall Water Splitting Dominated by Direct Ligand-to-Cluster Photoexcitation in Metal-Organic Frameworks.

Expanding the spectral response of photocatalysts to facilitate overall water splitting (OWS) represents an effective approach for improving solar spectrum utilization efficiency. However, the majority of single-phase photocatalysts designed for OWS primarily respond to the ultraviolet region, which accounts for a small proportion of sunlight. Herein, we present a versatile strategy to achieve broad visible-light-responsive OWS photocatalysis dominated by direct ligand-to-cluster charge transfer (LCCT) within metal-organic frameworks (MOFs). Three synthesized OWS MOFs, namely FeMCbz (M = Mn, Co, Ni), exhibited intrinsic OWS capability without the requirement for extra photosensitizer or sacrificial agent or cocatalyst. Among these, FeNiCbz was identified as the superior performer, and when dispersed with polyacrylonitrile nanofibers using electrospinning technology, it achieved the highest OWS rates of 170.2 and 85.1 μmol g h for H and O evolution, surpassing all previously documented MOF-based photocatalysts. Experimental and theoretical analyses revealed that direct LCCT played a crucial role in enhancing the photocatalytic efficiency, with exceptional performance of FeNiCbz attributed to its well-optimized energy level structures and highly efficient charge transfer mechanism. This work not only sets a benchmark in OWS MOF photocatalysts but also paves the way for maximizing solar spectrum utilization, thereby advancing renewable hydrogen production strategy.