Effect of boron on the performance of Pt/Al2O3 catalysts during propane dehydrogenation

ESTEBAN L. FORNERO; MARK SAEYS; VLADIMIR GALVITA; SHIWEN LI

Liege

Simposio; ANNUAL SCIENTIFIC MEETING IAP P7/05 FS2; 2016

Belgian science police office (Belspo)

The performance of supported Pt catalysts in light alkane dehydrogenation reactions are often optimized by the addition of promotors such as Sn, Zn, Ga, In and Ge. Generally the catalyst lifetime is enhanced by reducing carbon deposition and/or particle sintering at the expense of catalyst activity. Recently, our group has reported that the addition of small amounts boron enhances the stability of Ni1 and Co2 catalysts, without affecting their activity and selectivity. Furthermore, the effect of boron promotion on the selectivity of Pd hydrogenation catalysts was recently reported3. Based on these insights, we evaluated the effect of boron for Pt/Al2O3 catalysts in propane dehydrogenation reactions, combining kinetic experiments, computational catalysis and detailed characterization. The synthetized catalysts were tested at 600 ˚C and 1 bar with C3H8/H2/He and the amount of deposited carbon was determined by oxidation after reaction. Boron binds sufficiently strong at Pt subsurface octahedral sites to be stable against removal by hydrogen or carbon under dehydrogenation conditions. The presence of small amounts of boron (i.e., 1 wt%) is found to improve the catalyst stability and reduce the amount of coke deposition by at least a factor three.