Cu-MOF and its multi-walled carbon nano tube composite for the effective catalytic and electrocatalytic hydrogenation of 4-nitrophenol

A new and promising low-cost composite catalyst based on environmentally friendly multi-walled carbon nanotubes (CNTs) with highly active copper (Cu) containing MOF was developed for the chemical and electrochemical conversion of environmental pollutants such as 4-nitrophenol (4-NP) into beneficial 4-aminophenol (4-AP). Although Cu-MOF by itself has outstanding catalytic activity for converting 4-NP to 4-AP, the electrocatalytic performance is improved and the electrocatalyst's conductivity and durability are increased when CNTs are integrated with pristine Cu-MOF in electrochemical nitrophenol reduction. This integrated composite demonstrates exceptional prospects for the electrochemical transformation of 4-NP to 4-AP, one of the key intermediates in the synthesis of paracetamol. The electrochemical process achieves a remarkable 98 % conversion with 86 % yield efficiency. Simultaneously, 4-NP was chemically reduced using the composite catalyst in the presence of excess NaBH₄. The Cu-MOF catalyst has shown exceptional catalytic activity, converting 4-NP to 4-AP in a brief time of 72 seconds, whereas its CNT composite showed reduced activity. Further, the synthesized 4-AP is converted to paracetamol through an acetylation reaction with acetic anhydride, yielding a product of 60 % with a purity of 88 %, and NMR, GC-MS, and FT-IR spectroscopy confirmed the product. This work presents a novel approach for the conversion of pollutants without the generation of secondary pollutants or the need for sacrificial agents, offering a sustainable and efficient solution for industrial applications.