Synthesis of ZIF-67 derived Co-based catalytic membrane for highly efficient reduction of p-nitrophenol

It is significantly valuable to convert p-nitrophenol to p-aminophenol by catalysis. Herein, a novel Co@CN/CM catalytic membrane was synthesized, where ZIF-67 was first in-situ grown on the surface and in the pores of a ceramic membrane (CM) and then pyrolyzed to produce Co@N-doped carbon (Co@CN). The calcination temperature and Co²⁺ concentration significantly affect the microstructure of Co@CN/CM-X-Y (X represents the Co²⁺ molar concentration in methanol solution and Y represents the calcination temperature), and the corresponding catalytic properties for the p-nitrophenol reduction. The as-fabricated catalytic membrane Co@CN/CM-0.6–900 exhibits a superior catalytic activity, with a p-nitrophenol conversion of above 99% within 10 min, which is three times higher than that of Co@CN/CM-0.6–400. Co@CN/CM-0.6–900 also shows excellent reusability during five hydrogenation cycles. Abundant mesopores, high flux, many relatively isolated Co@CN particles with higher Co⁰ content, high N-pyrrolic content, and the protection function of CN are the reasons for the superior catalytic performance of Co@CN/CM-0.6–900.