The development of photocatalysts making full use of natural light sources is highly desired for the remediation of marine oil spill pollution, which is full of challenges. Herein, we demonstrate a well-defined visible-near-infrared-responsive g-CNH reduced decatungstate charge-transfer salt (RCD-CTS), which possess efficient light-absorption ability ranging from visible light to the near infrared region. The RCD-CTS photocatalyst exhibits excellent performance for photocatalytic removal of petroleum hydrocarbon. The structural characterization and theoretical calculation confirmed strong chemical interaction between components and partly reduction of decatungstate results in the plasmonic properties and the absorption of near infrared light. As a results, it is proposed that"hot electrons"transfer process generated by plasmon effect promotes the efficient separation of charge-carriers. Ultimately, this work sheds light on the discovery and application of visible-near-infrared-responsive optical materials that may be exploited further in artificial photosynthesis, solar energy conversion, and phototherapy.