The photocatalytic carbon dioxide reduction reaction (CO2RR) is an innovative and reliable technology to address the issues of energy shortage and climate change simultaneously. However, issues such as insufficient light absorption, rapid electron-hole recombination and low surface activity during CO2RR severely limit the catalysts’ efficiency for photocatalysis. In this study, we present nanohybrid N-CDs/FeNbO4 catalysts to overcome these challenges and achieve high-efficient photocatalytic conversion of CO2 to CH4. The enhancement process starts with the introduction of modified N-CDs, which have a broad light absorption capability. These N-CDs also help to modulate the interfacial charge transfer kinetics, leading to improved charge separation and transfer. This, in turn, enhances the multielectron transfer conversion selectivity of CO2 to CH4. Meanwhile, CO2 adsorption on the photocatalysts is increased due to the creation of oxygen vacancies and lattice stresses resulting from the introduction of N-CDs. This work presents a new approach for improving the photocatalytic performance by adjusting surface structure and interfacial behaviors.