Search

• Novel frameworks with metalloporphyrin (ZFs-TCPP-Ni) have been constructed. • ZFs-TCPP-Ni framework serves as biomimetic photocatalyst to CO 2 photoreduction. • The biomimetic system exhibits a remarkable photocatalytic CO 2 -to-CO conversion. The development of biomimetic catalysis for efficient photoreduction of CO 2 is an effective alternative to address energy problems. However, amelioration on the construction of biomimetic catalysts for elevated photocatalytic performance is still challenging and demanded. Herein, a bioinspired artificial photosynthesis system is constructed based on ZrO 2 nanoframes (ZFs) and metalloporphyrin to mimic the morphology of trees. The robust backbone of the framework and the bio-inspiring porphyrins anchored on the surface of ZFs function as the strong trunk and well-ordered leaves of a tree, respectively. The biomimetic system achieves an evolution yield of 35.3 μmol during 3 h reaction with 93.1% CO selectivity and 1.84% CO apparent quantum efficiency (A.Q.E.), which is about 60.8 times larger than that of pure porphyrin (Ni) (0.58 μmol). Detailed analysis reveals that the catalytic system could not only achieve fast separation of the photogenerated carriers and effective CO 2 activation but also possess suitable energy levels, which could efficiently transfer electrons to the Ni catalytic sites to improve the photocatalytic activity. Furthermore, the good recycling tests could be explained by the robust supporting of frameworks as well as the strong binding of the Zr atoms and carboxyl groups of porphyrins. This work presents a simple model of biomimetic catalysts and outlines possible strategies for other biomimetic manufactures. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Ultrathin holey Co 3 O 4 -NS were synthesized by a facile MOF-engaged strategy. • Co 3 O 4 -NS significantly promote electron transport and CO 2 adsorption. • Co 3 O 4 -NS displays an excellent photocatalytic performance for CO 2 conversion. Abstract Reducing carbon dioxide (CO 2) to various value-added chemical products by photocatalysis could effectively alleviate the serious problems of global warming and energy shortages. Currently, most commonly prepared photocatalysts present poor performance under visible light irradiation. In this study, we adopted a facile, scalable and controllable approach to prepare ultrathin two-dimensional (2D) porous Co 3 O 4 catalysts (Co 3 O 4 -NS) by air calcining of the ultrathin metal-organic framework (MOFs) nanosheet templates to validly reduce CO 2 with a Ru-based photosensitizer under visible light irradiation. Benefitting from the structural nature of MOFs precursors, the calcined Co 3 O 4 -NS inherit the morphology of 2D and well-developed porosity, which support the transport of electrons, enhance the adsorption of CO 2 molecules, and render abundant catalytic sites for CO 2 activation. As a result, the CO generation rate is approximately 4.52 μmol·h−1 with selectivity of 70.1%, which is superior to the Co 3 O 4 bulk catalysts (Co 3 O 4 -BK). Additionally, density functional theory (DFT) calculations reveal that the model of Co 3 O 4 monolayer has stronger CO 2 adsorption energy than that of the Co 3 O 4 bulk, which is beneficial for the CO 2 -to-CO conversion. This MOF-engaged strategy provides new insight into the controlled synthesis of advanced ultrathin holey nanosheets to improve the efficiency of photocatalytic CO 2 reduction. [ABSTRACT FROM AUTHOR]

• The Co-Co LDH/TNS nanoarray was synthesized via an in situ MOF-derived strategy. • The composite remarkably facilitate the migration and separation of charge carriers. • The composite displays an excellent photocatalytic performance for CO 2 conversion. Converting carbon dioxide (CO 2) to multiple energy-rich chemicals by photocatalysis could validly mitigate the severe issues of climate changes and energy shortages. Exploring efficient catalysts for enhancing the performance of CO 2 photoreduction is still challenging. Herein, a novel three-dimensional hierarchical Co-Co layered double hydroxide/Ti 3 C 2 T X nanosheets (Co-Co LDH/TNS) nanoarray was successfully prepared via an in-situ MOF-derived strategy. This wise design rationally integrates the functional and structural merits of active Co species with conductive MXene to a hierarchical nanoarray architecture composed of ultrathin nanosheets, which can remarkably promote separation of photogenerated charge carriers and accelerate electrons transmission. Benefitting from these features, the hierarchical Co-Co LDH/TNS composites manifest significant enhancement on the CO 2 -to-CO evolving rate (1.25 × 104 µmol h−1 g−1) under illumination (>400 nm) with a high apparent quantum efficiency (0.92%) and excellent stability. Our work demonstrates that 3D hybrid structure composed of MXene species can serve as promising candidates for CO 2 photoreduction, providing fundamental guidance to improve photocatalytic performance by rational engineering of complex hierarchical architecture materials. [ABSTRACT FROM AUTHOR]