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

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