Herein,　a　Pd　nanoparticle　catalyst　supported　on　N-doped　TiO2　(Pd/N-TiO2)　was　prepared　by　a　chemical　reduction　method　and　evaluated　for　catalytic　performance　in　the　CO　+　NO　reaction　with　and　without　visible　light　irradiation.　It　was　found　that　the　Pd/N-TiO2　catalyst　exhibited　excellent　catalytic　activity　even　at　low　temperatures,　and　upon　introducing　visible　light,　its　catalytic　performance　was　drastically　enhanced.　The　results　of　in　situ　diffuse　reflectance　infrared　Fourier　transform　spectra　(in　situ　DRIFTS)　indicated　that　visible　light　benefited　the　adsorption　and　activation　of　both　NO　(at　N-TiO2　sites)　and　CO　(at　Pd　sites)　as　well　as　formation　of　active　intermediates　(e.g.　Ti4+-NO-　and　CO-Pd).　On　the　basis　of　Raman　spectroscopy,　electron　paramagnetic　resonance　(EPR)　and　X-ray　photoelectron　spectroscopy　(XPS)　results,　it　was　proposed　that　Pd/N-TiO2　possessed　numerous　surface　oxygen　vacancies　(SOVs-Ti3+),　and　visible　light　irradiation　could　promote　the　generation　of　SOVs　and　increase　in　the　Pd　surface　electron　density　by　photo-induced　electron　(from　N2p　to　Ti3d　orbit)　transfer　from　N-TiO2　to　Pd　nanoparticles,　resulting　in　enhanced　adsorption　and　activation　of　CO　and　NO.　Thus,　a　strengthened　photo-assisted　effect　for　the　CO　+　NO　reaction　occurred　on　Pd/N-TiO2.　©　2019　The　Royal　Society　of　Chemistry.