Promotional effect of Cu on the structure and chloronitrobenzene hydrogenation performance of carbon nanotube and activated carbon supported Pt catalysts

The promotional effect of Cu on the performance of supported Pt catalysts in the selective hydrogenation of ortho- and para-chloronitrobenzene was studied at unprecedented large substrate/Pt molar ratio (20,000) using carbon nanotubes and activated carbon as supports. The catalysts were characterized by N2 adsorption at −196 °C, H2 chemisorption, TEM, TPR and XPS in order to correlate the corresponding properties with catalytic performance. Strong interactions between Pt and Cu result in partial coverage of the Pt surface by Cu. It is suggested that the superficial Cu species activate the NO bond of chloronitrobenzene and also inhibit the adsorption of the desired product chloroaniline. Thus, the bimetallic catalysts exhibited excellent performance in producing selectively chloroanilines (>99%), in comparison to monometallic catalysts (91–98%). Moreover, the stability was much improved in comparison to the monometallic catalyst.Financial support for this work was provided by Fundação para a Ciência e a Tecnologia (FCT) and FEDER under program COMPETE (FCT Pest-C/EQB/LA0020/2011). OSGPS thanks FCT for the research grant SFRH/BPD/80435/2011.Peer Reviewe