Abstract
Thermocatalytic nonoxidative ethane dehydrogenation(EDH)is a promising strategy for ethene produc-tion but suffers from intense energy consumption and poor catalyst durability;exploring technology that permits efficient EDH by solar energy remains a giant challenge.Herein,we present that an oxygen va-cancy(Ov)-rich LaVO4(LaV04-Ov)catalyst is highly active and stable for photocatalytic EDH,through a dynamic lattice oxygen(Olatt.)and Ov co-mediated mechanism.Irradiated by simulated sunlight at mild conditions,LaVO4-Ov effectively dehydrogenates undiluted ethane to produce C2H4 and CO with a con-version of 2.3％.By loading a small amount of Pt cocatalyst,the evolution and selectivity of C2H4 are en-hanced to 275 μmol h-1 g-1 and 96.8％.Of note,LaVO4-Ov appears nearly no carbon deposition after the reaction.The isotope tracked reactions reveal that the consumed Olatt.recuperates by exposing the used catalyst with O2,thus establishing a dynamic cycle of Olatt,and achieving a facile catalyst regeneration to preserve its intrinsic activity.The refreshed LaVO4-Ov exhibits superior reusability and delivers a turnover number of about 305.The Ov promotes photo absorption,boosts ethane adsorption/activation,and accel-erates charge separation/transfer,thus improving the photocatalytic efficiency.The possible photocatalytic EDH mechanism is proposed,considering the key intermediates predicted by density functional theory(DFT)and monitored by in-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS).
NETL
NSTL
万方数据