Flower-like CdS/CdV2O6 composite for visible-light photoconversion of CO2 into CH4

Highlights: • The synthesized nanocomposite minimize the recombination of charge carriers. • The fabricated material can be used for the photoreduction of CO2 into CH4 under visible light. • The formation of composite improves the stability of the photocatalyst. Flower-like CdS/CdV₂O₆ composite has been used in the present work for the visible-light (λ ≥ 420 nm) photoconversion of CO₂ into CH₄. CdV₂O₆ has been synthesized by simple hydrothermal method. Limited chemical conversion route (LCCR) has been used for the synthesis of novel efficient visible light driven CdS/CdV₂O₆ composite. Several characterization techniques such as X-ray diffraction (XRD), high resolution electron microscopy (HRTEM), scanning electron microscopy (SEM), UV/visible spectroscopy, X-ray photoelectron spectroscopy (XPS) and Brunauer–Emmett–Teller (BET) have been used to characterize the as synthesized photocatalysts. XRD confirms the formation of monoclinic structure of CdV₂O₆ and orthorhombic phase of CdS in the nanocomposite. HRTEM and SEM results reveal rod-like morphology of CdV₂O₆ while CdS/CdV₂O₆ is in the form of well-shaped bunches of flower-like structures. XPS is used to determine the alignment of energy levels against the standard hydrogen electrode (SHE). The as-synthesized flower-like composites have then been employed as efficient photocatalysts for visible-light photoconversion of CO₂ into CH₄. The CdS/CdV₂O₆ composite results in visibly higher yield of methane than that of single semiconductors that might be attributed to the suppressed recombination of the photogenerated charge carriers. Flower-like CdS/CdV₂O₆ composite also exhibits tremendous photostability than the individual counterparts.