Thiophene decomposition on Pd(111) forms S and C-4 species: A laser-induced thermal desorption/Fourier transform mass spectrometry study

The data presented here show that Pd(lll) can directly activate thiophene decomposition resulting in the deposition of sulfur and the formation of C-4 species, most likely C4H4 or possibly C4H5, on the surface. Temperature programmed reaction (TPR) studies of a 0.2 L exposure of thiophene show some reversible, but primarily irreversible adsorption. No C- or S-containing reaction products desorb during TPR. However, laser induced thermal desorption (LITD) with Fourier transform mass spectrometry (FTMS) can be used to monitor the surface composition prior to conventional desorption. LITD/FTMS shows that thiophene is stable to approximately 280 K. Above 300 K, 1,3-butadiene is observed. The yield of 1,3-butadiene on the surface, as observed by LITD/FTMS, is estimated to be 30% of the initial thiophene signal.