This　work　aims　at　depositing　high-crystallinity　NiOx　nanoparticles　on　the　surface　of　graphitic　carbon　nitride　(g-CN)　nanosheets　to　improve　light-driven　hydrogen　(H2)　generation.　Notably,　assisted　by　transmission　electron　microscopy　(TEM),　we　can　discover　that　the　solvothermal-processed　NiOx　nanoparticles　attached　over　g-CN　possess　a　great　crystallinity　with　a　diameter　size　of　approx.　3–5　nm.　As　a　result,　the　NiOx-nanoparticle　loading　can　obviously　enhance　the　H2　evolution　rate　(HER)　of　g-CN　from　0　to　307　μmol　h−1　g−1　under　irradiation　of　AM1.5　spectra.　Meanwhile,　the　apparent　quantum　efficiencies　(AQE)　at　400　nm　can　even　approach　the　superior　1.5%.　What＇s　more,　X-ray　photoelectron　spectroscopy　(XPS)　and　transient　absorption　(TA)　spectra　contribute　to　propose　that　the　photogenerated　electrons　can　first　reduce　Ni3+　into　metallic　nickel　(Ni0),　and　then　the　H+　prefers　to　be　reduced　on　the　surface　of　Ni2+/Ni0　sites.　©　2021　Elsevier　B.V.