All-inorganic perovskite/graphitic carbon nitride composites for CO2 photoreduction into C1 compounds under low concentrations of CO2

Abstract

CsPbBr₃ is widely used in solar cells and LEDs for its excellent photoelectric properties that are also attractive for CO₂ photoreduction, but it is less used in the photocatalytic reduction of CO₂ mainly owing to its limited charge separation efficiency. To alleviate this issue, herein, all-inorganic orthorhombic CsPbBr₃ was combined with graphitic carbon nitride (g-C₃N₄) and the resultant composite (CsPbBr₃@g-C₃N₄) showed enhanced activity in CO₂ photoreduction. Under the irradiation of AM1.5 filter for 12 h, CO₂ was converted into CH₄ and CO with high selectivity to methane (91%) and the total amount of gaseous products up to ∼300 μmol g⁻¹. This reactivity is 6-fold and 4-fold higher than that of pure g-C₃N₄ and CsPbBr₃, respectively. CsPbBr₃@g-C₃N₄ also shows excellent catalytic activity at low concentrations of CO₂. Studies of energy band level and steady-state and transient photoluminescence spectroscopy indicated that the incorporation of CsPbBr₃ and g-C₃N₄ increases charge separation, which may result in sharply enhanced catalytic efficiency. This study has provided opportunities for the combination of CsPbBr₃ and other semiconductor catalysts for the photocatalytic reduction of CO₂.