In Situ Growth of Cs₃Bi₂Br₉ Quantum Dots on Bi-MOF Nanosheets via Cosharing Bismuth Atoms for CO₂ Capture and Photocatalytic Reduction

Abstract

Given the global warming caused by excess CO 2 accumulation in the atmosphere, it is essential to reduce CO 2 by capturing and converting it to chemical feedstock using solar energy. Herein, a novel Cs 3 Bi 2 Br 9 /bismuth-based metal−organic framework (Bi-MOF) composite was prepared via an in situ growth strategy of Cs 3 Bi 2 Br 9 quantum dots (QDs) on the surface of Bi-MOF nanosheets through coshared bismuth atoms. The prepared Cs 3 Bi 2 Br 9 /Bi-MOF exhibits bifunctional merits for both the high capture and effective conversion of CO 2 , among which the optimized 3Cs 3 Bi 2 Br 9 /Bi-MOF sample shows a CO 2 −CO conversion yield as high as 572.24 μmol g −1 h −1 under the irradiation of a 300 W Xe lamp. In addition, the composite shows good stability after five recycles in humid air, and the CO 2 photoreduction efficiency does not decrease significantly. The mechanistic investigation uncovers that the intimate atomic-level contact between Cs 3 Bi 2 Br 9 and Bi-MOF via the coshared atoms not only improves the dispersion of Cs 3 Bi 2 Br 9 QDs over Bi-MOF nanosheets but also accelerates interfacial charge transfer by forming a strong bonding linkage, which endows it with the best performance of CO 2 photoreduction. Our new finding of bismuth-based metal−organic framework/lead-free halide perovskite by cosharing atoms opens a new avenue for a novel preparation strategy of the heterojunction with atomic-level contact and potential applications in capture and photocatalytic conversion of CO 2 .

Critical Roles of Octahedron Bilayer Surface/Interior Bromide Defects in Photodynamics of Multi-Quantum-Well-Structured Cesium Bismuth Bromide

“…The bromide interstitials on the surfaces and within the interior of the octahedral bilayers separately play critical roles in the radiative and non-radiative transition processes. The calculated non-radiative lifetime agrees with the measured value. ,, …”

“…The calculated non-radiative lifetime agrees with the measured value. 15,31,32 Cs 3 Bi 2 Br 9 has a trigonal structure (space group P3̅ m1; Figure 1a) at room temperature. 9 The corner-sharing octahedral [BiBr 6 ] 3− units form the periodic quantum-well-like bilayers in supposed that it is assigned to the band edge absorption, 8,14,25 and others supposed that it belongs to the exciton absorption.…”

“…As shown in the inset of Figure 4c, τ e equals 184 ns when N D of Br i2 equals a reasonable value of 1 × 10 15 cm −3 , and the order of magnitude of this lifetime agrees with the measured value in Cs 3 Bi 2 Br 9 within the errors. 15,31,32 It suggests that Br i2 has a significant contribution to the non-radiative recombination in Cs 3 Bi 2 Br 9 , and this efficient multiphonon recombination process explains the low quantum yield of Cs 3 Bi 2 Br 9 . 35 The experimental study had indicated that the photoinduced lattice expansion can affect the optical properties of Cs 3 Bi 2 Br 9 .…”

In Situ Growth of Lead-Free Cs2CuBr4 Perovskite Quantum Dots in KIT-6 Mesoporous Molecular Sieve for CO2 Adsorption, Activation, and Reduction

“…Besides the charge transport property, the CO 2 adsorption capacity of the photocatalyst is another crucial factor determining its CO 2 reduction activity . Therefore, the CO 2 adsorption capacity of the CCB PQDs and CCB@KIT-6 was analyzed.…”

“…Besides the charge transport property, the CO 2 adsorption capacity of the photocatalyst is another crucial factor determining its CO 2 reduction activity. 35 Therefore, the CO 2 adsorption capacity of the CCB PQDs and CCB@KIT-6 was analyzed. Figure 6c presents the CO 2 adsorption/desorption isotherms of CCB PQDs and CCB@KIT-6, which indicates that CCB@KIT-6 exhibits higher CO 2 adsorption capacity than pristine CCB, thus promoting the subsequent CO 2 reduction reaction.…”