The surface chemistry of diethyl disulfide on copper

摘要

The surface chemistry of diethyl disulfide (DEDS) is studied on polished copper foils and a Cu(lll) single crystal, using temperature-programmed desorption, reflection absorption infrared spectroscopy and X-ray photoelectron spectroscopy. A portion of the DEDS reacts to form ethyl thiolate species even at -80 K, where reaction is complete on heating to -200 K. The resulting thiolate species decompose to form either ethylene or ethane at -380 to -400 K. The selectivity to ethane increases relative to ethylene formation at higher coverages, due to surface crowding that inhibits β-hydride elimination reactions thereby lowering the ethylene yield. Such a change in orientation is confirmed by changes in relative intensities of the ethyl group vibrational modes with coverage.