Multi-channel ceramic catalytic membrane for highly efficient and continuous hydrogenation of p-nitrophenol

The hydrogenation of p-nitrophenol (4-NP) to p-aminophenol (4-AP) transforms a detrimental pollutant into a valuable chemical, while conventional powder catalysts face challenges in continuous operation due to the limitations in separation and recovery processes. Here, we developed a catalytic membrane by loading Co onto a polydopamine (PDA)-modified multi-channel ceramic membrane (CM) with subsequent pyrolysis. PDA plays a crucial role in capturing Co ions, facilitating the reduction of Co ions, and preventing the leaching of Co nanoparticles (NPs) from the membrane. Fine-tuning the DA and cobalt nitrate concentrations, along with the pyrolysis temperature, results in the catalytic membrane with abundant Co NPs, enriched surface Co content, and sufficient graphitic N, which significantly enhances the reduction of 4-NP to 4-AP in a flow-through catalytic membrane reactor. The Co@CM-3.0–0.1–700 demonstrates a remarkable activity of converting 4-NP at a rate of 67.4 h⁻¹, maintaining stability for a continuous operation of 300 min. This study pioneers highly efficient catalytic membrane for the transformation of detrimental pollutant 4-NP to a valuable chemical 4-AP.