In Situ Coating CsPbBr3 Nanocrystals with Graphdiyne to Boost the Activity and Stability of Photocatalytic CO2 Reduction.

The instability and low inferior catalytic activity of metal-halide perovskite nanocrystals are crucial issues for promoting their practical application in the photocatalytic field. Herein, we in situ coat a thin graphdiyne (GDY) layer on CsPbBr3 nanocrystals based on a facile microwave synthesis method, and employ it as a photocatalyst for CO2 reduction. Under the protection of GDY, the CsPbBr3-based photocatalyst delivers significantly improved stability in a photocatalytic system containing water concomitant with enhanced CO2 uptake capacity. The favorable energy offset and close contact between CsPbBr3 and GDY trigger swift photogenerated electron transfer from CsPbBr3 to doping metal sites in GDY, boosting a remarkable improvement in the photocatalytic performance for CO2 reduction. Without adding traditional sacrificial reductants, the cobalt-doped photocatalyst achieves a high yield of 27.7 µmol g-1 h-1 for photocatalytic CO2 conversion to CO based on water as a desirable electron source, which is about 8 times higher than that of pristine CsPbBr3 nanocrystals.

Ultrathin and Small-Size Graphene Oxide as an Electron Mediator for Perovskite-Based Z-Scheme System to Significantly Enhance Photocatalytic CO2 Reduction.

The judicious design of efficient electron mediators to accelerate the interfacial charge transfer in a Z-scheme system is one of the viable strategies to improve the performance of photocatalysts for artificial photosynthesis. Herein, ultrathin and small-size graphene oxide (USGO) nanosheets are constructed and employed as the electron mediator to elaborately exploit an efficient CsPbBr3 -based all-solid-state Z-scheme system in combination with α-Fe2 O3 for visible-light-driven CO2 reduction with water as the electron source. CsPbBr3 and α-Fe2 O3 can be closely anchored on USGO nanosheets, owing to the existence of interfacial strong chemical bonding behaviors, which can significantly accelerate the photogenerated carrier transfer between CsPbBr3 and α-Fe2 O3 . The resultant improved charge separation efficiency endows the Z-scheme system exhibiting a record-high electron consumption rate of 147.6 µmol g-1 h-1 for photocatalytic CO2 -to-CO conversion concomitant with stoichiometric O2 from water oxidation, which is over 19 and 12 times higher than that of pristine CsPbBr3 nanocrystals and the mixture of CsPbBr3 and α-Fe2 O3 , respectively. This work provides a novel and effective strategy for improving the catalytic activity of halide-perovskite-based photocatalysts, promoting their practical applications in the field of artificial photosynthesis.

A halide perovskite as a catalyst to simultaneously achieve efficient photocatalytic CO2 reduction and methanol oxidation.

A halide perovskite based photocatalyst has been demonstrated for the first time to simultaneously achieve efficient photocatalytic CO2 reduction and methanol oxidation, exhibiting an exciting yield of 1835 µmol g-1 for photocatalytic CO2-to-CO conversion. Moreover, almost stoichiometric value-added formic acid can be produced from methanol oxidation.

Water-Tolerant Lead Halide Perovskite Nanocrystals as Efficient Photocatalysts for Visible-Light-Driven CO2 Reduction in Pure Water.

Lead halide perovskite (LHP) nanocrystals have recently been actively investigated for photocatalysis, owing to their inexpensive fabrication and excellent optoelectronic properties. However, LHP nanocrystals have not been used for artificial photosynthesis in aqueous solution, owing to their high sensitivity to water. In this study, water-tolerant cobalt-doped CsPbBr3 /Cs4 PbBr6 nanocrystals have been prepared with the protection of hexafluorobutyl methacrylate. The resultant materials are employed as efficient photocatalysts for visible-light-driven CO2 reduction in pure water. The perovskite nanocrystals with 2 % cobalt doping afford an impressive overall yield of 247 µmol g-1 for photocatalytic CO2 conversion into CO and CH4 , using water as an electron source. This study represents a significant step for practical artificial photosynthesis by using LHP nanocrystals as photocatalysts in aqueous solution.

Engineering a CsPbBr3-based nanocomposite for efficient photocatalytic CO2 reduction: improved charge separation concomitant with increased activity sites.

Metal-halide perovskite nanocrystals have emerged as one of the promising photocatalysts in the photocatalysis field owing to their low-cost and excellent optoelectronic properties. However, this type of nanocrystals generally displays low activity in photocatalytic CO2 reduction owing to the lack of intrinsic catalytic sites and insufficient charge separation. Herein, we functionalized CsPbBr3 nanocrystals with graphitic carbon nitride, containing titanium-oxide species (TiO-CN) to develop an efficient composite catalyst system for photocatalytic CO2 reduction using water as the electron source. Compared to its congener with pristine CsPbBr3, the introduction of TiO-CN could not only increase the number of active sites, but also led to a swift interfacial charge separation between CsPbBr3 and TiO-CN due to their favorable energy-offsets and strong chemical bonding behaviors, which endowed this composite system with an obviously enhanced photocatalytic activity in the reduction of CO2 to CO with water as the sacrificial reductant. Over 3-fold and 6-fold higher activities than those of pristine CsPbBr3 nanocrystals and TiO-CN nanosheets, respectively, were observed under visible light irradiation. Our study provides an effective strategy for improving the photocatalytic activity of metal-halide perovskite nanocrystals, thus promoting their photocatalytic application in the field of artificial photosynthesis.