Exploitation of the novel, robust, and advanced photocatalytic systems with high efficiency is the present demand for clean, green, and sustainable energy production. Carbon quantum dots (CQDs) have attracted tremendous interest in efficient H-2 evolution from photocatalysis due to its remarkable visible-light harvesting and electron transport properties. Here, for the first time, a smart ternary nanocomposite comprises encapsulated CQDs with LaFeO3 spherical nanoparticles and CdS nanorods is synthesized by a simple hydrothermal procedure for the efficient photocatalytic H-2 evolution under sunlight illumination. PXRD, FT-IR, FE-SEM, TEM, and XPS studies are performed to ensure the successful fabrication of ternary LaFeO3/CdS/CQD nanocomposite. The efficient H-2 evolution rate (HER) of 25,302 mu mol h(-1) g(cat)(1) is achieved for LaFeO3/CdS/CQD nanocomposite, which is 602.4, 2.6, 29.8, 2.0 and 1.1 times higher than that of pristine LaFeO3, pristine CdS, and composites such as LaFeO3/CdS, LaFeO3/CQD, and CdS/CQD. Photocurrent and lifetime PL studies reveal, encapsulation of CQDs with the LaFeO3/CdS heterojunction can facilitate easy and efficient separation of photo-generated excitons. Altogether the fabrication of CQDs provides an ideal avenue for the development of high potential advanced photocatalytic systems for sustainable H-2 production with remarkable efficiencies. (C) 2020 Elsevier Inc. All rights reserved.