Water-stable perovskite-like catalysts based on 4,5-imidazoledicarboxylic acid for efficient photocatalytic removal of U(VI)

Metal halide perovskites (MHPs) have emerged as highly promising materials in the field of photocatalysis due to their unique and advantageous physicochemical properties. However, their limited water stability remains a primary bottleneck hindering further practical applications. Here, we synthesized a series of novel organic–metal hybrid interlayer (OMI) phase-bridged perovskite-like photocatalysts ([Pb 2 Br x I 3-x ] + [Pb 2+ (imdc 3− )] (x = 0,1,2, corresponding to compounds 1–3)) based on 4,5-imidazoledicarboxylic acid for photocatalytic removal of U(VI). The direct coordination assembly between the OMI and inorganic layers endows these materials with exceptional intrinsic stability in water. Notably, compounds 1–3 can maintain excellent stability for up to one month in aqueous solutions; and compound 2 keeps structural stability across different pH solutions. By tuning the halogen composition, compound 2 achieves markedly improved photogenerated carrier separation and charge transfer, as verified by steady-state and time-resolved photoluminescence spectroscopy, transient photocurrent responses, and density functional theory (DFT) calculations. DFT further reveals suitable U(VI) adsorption sites and excellent charge-transfer capability. As a result, compound 2 delivers a U(VI) removal rate of 99.3% from a 20 ppm solution under simulated sunlight irradiation within 180 min, along with outstanding selectivity, stability, and recyclability. This work provides a promising strategy for designing efficient and stable perovskite-like photocatalysts for the photoreduction of U(VI). Download: Download high-res image (119KB) Download: Download full-size image The direct coordination assembly between the OMI and inorganic layers ([Pb 2 BrI 2 ] + ) endows perovskite-like catalyst [Pb 2 BrI 2 ] + [Pb 2+ (imdc 3− )] with exceptional intrinsic stability in water, which demonstrates excellent photocatalytic performance in U(VI) removal, along with outstanding selectivity, stability, and recyclability.