Thermocatalytic　nonoxidative　ethane　dehydrogenation　(EDH)　is　a　promising　strategy　for　ethene　production　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　vacancy　(Ov)-rich　LaVO4　(LaVO4-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　conversion　of　2.3%.　By　loading　a　small　amount　of　Pt　cocatalyst,　the　evolution　and　selectivity　of　C2H4　are　enhanced　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　accelerates　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).　©　2023