Photoirradiation-Induced Capacitance Enhancement in the h-WO3/Bi2WO6 Submicron Rod Heterostructure under Simulated Solar Illumination and Its Postillumination Capacitance Enhancement Retainment from a Photocatalytic Memory Effect

Exploring a Ni-N4 Active Site-Based Conjugated Microporous Polymer Z-Scheme Heterojunction Through Covalent Bonding for Visible Light-Driven Photocatalytic CO2 Conversion in Pure Water

Designing photocatalysts with efficient charge transport and abundant active sites for photocatalytic CO2 reduction in pure water is considered a potential approach. Herein, a nickel-phthalocyanine containing Ni-N4 active sites-based conjugated microporous polymer (NiPc-CMP), offering highly dispersed metal active sites, satisfactory CO2 adsorption capability, and excellent light harvesting properties, is engineered as a photocatalyst. By virtue of the covalently bonded bridge, an atomic-scale interface between the NiPc-CMP/Bi2 WO6 Z-scheme heterojunction with strong chemical interactions is obtained. The interface creates directional charge transport highways and retains a high redox potential, thereby enhancing the photoexcited charge carrier separation and photocatalytic efficiency. Consequently, the optimal NiPc-CMP/Bi2 WO6 (NCB-3) achieves efficient photocatalytic CO2 reduction performance in pure water under visible-light irradiation without any sacrificial agent or photosensitizer, affording a CO generation rate of 325.9 µmol g-1 with CO selectivity of 93% in 8 h, outperforming those of Bi2 WO6 and NiPc-CMP, individually. Experimental and theoretical calculations reveal the promotion of interfacial photoinduced electron separation and the role of Ni-N4 active sites in photocatalytic reactions. This study presents a high-performance CMP-based Z-scheme heterojunction with an effective interfacial charge-transfer route and rich metal active sites for photocatalytic CO2 conversion.

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

Given the global warming caused by excess CO₂ accumulation in the atmosphere, it is essential to reduce CO₂ by capturing and converting it to chemical feedstock using solar energy. Herein, a novel Cs₃Bi₂Br₉/bismuth-based metal-organic framework (Bi-MOF) composite was prepared via an in situ growth strategy of Cs₃Bi₂Br₉ quantum dots (QDs) on the surface of Bi-MOF nanosheets through coshared bismuth atoms. The prepared Cs₃Bi₂Br₉/Bi-MOF exhibits bifunctional merits for both the high capture and effective conversion of CO₂, among which the optimized 3Cs₃Bi₂Br₉/Bi-MOF sample shows a CO₂-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 CO₂ photoreduction efficiency does not decrease significantly. The mechanistic investigation uncovers that the intimate atomic-level contact between Cs₃Bi₂Br₉ and Bi-MOF via the coshared atoms not only improves the dispersion of Cs₃Bi₂Br₉ 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 CO₂ 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 CO₂.