Highly active and selective catalytic hydrogenation of p-chloronitrobenzene to p-chloroaniline on Pt@Cu/TiO2

It is still a great challenge to achieve trade-off between catalytic activity and selectivity on supported Pt catalysts for the catalytic hydrogenation of p-chloronitrobenzene. Here through a two-step photodeposition method, bimetallic [email protected]/TiO2 catalysts with different Cu contents were synthesized to deal with this problem. For comparison, Pt/TiO2 and Cu/TiO2 were also synthesized using the photodeposition method. Characterization results suggested that Cu was site-specifically deposited on Pt particle surface and core-shell nanocomposites with Pt as core and Cu as shell were formed on TiO2. Additionally, electron transfer between Pt and Cu occurred in bimetallic nanoparticles, resulting in negatively charged Pt and positively charged Cu. For the catalytic hydrogenation of p-chloronitrobenzene, Pt/TiO2 exhibited the highest catalytic activity but lowest selectivity among the tested catalysts. Bimetallic catalysts with Cu content equal to the monolayer dispersion capacity displayed a slightly lower activity than that of Pt/TiO2 and 100% selectivity to p-chloroaniline. A lower Cu content led to decreased p-chloroaniline selectivity, while a higher Cu content resulted in markedly inhibited catalytic activity despite of 100% p-chloroaniline selectivity. The findings in the present study indicate that [email protected]/TiO2 with a monolayer Cu content is a prominent catalyst with high activity and selectivity.