Low-crystalline Ni(OH)2 ultrathin nanosheets upcycled from solid wastes for efficient photoconversion of low-concentration CO2

Low-crystalline ultrathin nanosheets (UNSs) hold great potential for efficient photoreduction of anthropogenic CO2, while developing green synthetic methodologies and elucidating the structure-performance relationship remain significant challenges. Here, via a CaO-mediated strategy, we demonstrate a facile strategy for the largescale production of low-crystalline Ni(OH)2 UNSs from industrial wastes. The resultant Ni(OH)2 UNSs deliver a superior CO formation rate of 9.2 mu mol h-1 with a high selectivity of 93.1 % in low-concentration CO2 (10 %), which remarkably outperforms that of Ni(OH)2 NSs with high crystalline. Experimental and theoretical investigations demonstrate that the boosted performance originates from the fully exposed oxygen vacancies and low-coordination Ni sites, which facilitates the separation of photogenerated charge pairs and the adsorption and activation of diluted CO2. This work demonstrates a sustainable strategy for the large-scale synthesis of lowcrystalline layered metal hydroxides, paving new avenues for the high-value utilization of industrial wastes in mitigating climate change.