Fabrication of perovskite@MOF composites as an alternative for noble metal catalysts in hydrogenation of nitroarenes: An investigation of transition metals doping on catalytic performance and RSM modeling of reaction conditions

Abstract

Nitroaromatic compounds (NACs) are generally utilized in various industries and are known as essential intermediates in synthesizing valuable products. Herein, we have developed a highly beneficial and eco-friendly catalytic hydrogenation of NACs. For this purpose, a novel perovskite@MOF composite, as an alternative catalyst to expensive and noble metals, has first been synthesized by encapsulating LaMnO3 into MOF-5 pores. The fabricated composite showed excellent catalytic capability, and it can promote the hydrogenation of NACs by NaBH4 under mild conditions. A high yield of up to 88.34% can be achieved by LaMnO3@MOF-5 for 4-nitrophenol (4-NP) as a model reaction, compared with only 49.02% for LaMnO3. Therefore, MOF-5 is a suitable host for the LaMnO3 catalyst and produces a synergistic effect. In the next step, some transition metal ions were used to dope the catalyst to enhance the catalytic activity, and the best catalyst was selected. Then, the hydrogenation process was modeled and optimized using the Box–Behnken design. It clearly shows that the conversion of up to 92.35%, 97.56%, and 96.14%, TOF of 2.60, 2.68, and 2.87 min−1, and phenomenal apparent rate constant (K) of 1.73 × 10−2, 1.74 × 10−2, and 1.78 × 10−2 s−1 can be obtained by Cu(II), Ni(II), and Co(II) doped composites, respectively. To evaluate and prove the efficacy of the Co-P@MOF catalyst, we also reduced some NACs under the obtained optimal conditions.