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Photocatalytic conversion of CO2 to added‐value fuels or chemicals is a promising technology for the effective utilization of the disturbing greenhouse gas, but its economic benefit is limited either by low efficiency due to the difficulty of water oxidation or by the employment of expensive sacrificial reagents. To overcome this dilemma, herein, an effective strategy is reported for the resourceful utilization of CO2 by creating an eco‐friendly bifunctional photocatalyst to achieve CO2 photoreduction concurrent with methanol photooxidation to the uniform product of formic acid for the first time. The bifunctional photocatalyst is elaborately constructed by in situ encapsulating lead‐free double perovskite (Cs2AgBiBr6, abbreviated as CABB) nanocrystals into the pores of Fe‐based metal−organic framework (MIL‐101(Fe)). The tight contact between CABB and MIL‐101(Fe) in the resultant CABB/MIL‐101(Fe) composite facilitates the efficient spatial separation of photogenerated carriers, which leads to the division of reduction and oxidation functional units. CABB/MIL‐101(Fe) composites can unify the redox products into formic acid, reaching an impressive formation yield of 1375 μmol g−1 h−1 with a high selectivity of 97.8%. This work provides a viable strategy for the efficient photosynthesis of formic acid, promoting the cost‐effective utilization of CO2. [ABSTRACT FROM AUTHOR]

Activation and catalytic transformation of C–H bonds under mild conditions has long been a great challenge for the chemical industry. Herein, we report a halide-perovskite-based photocatalyst composed of manganese-doped CsPbBr3 decorated on BiVO4 for the efficient and selective transformation of nonpolar CH4 to oxygenates using air as an oxidant. At room temperature and atmospheric pressure, the yield and selectivity of oxygen-containing hydrocarbons (CH3OH and HCHO) from photocatalytic CH4 oxidation are as high as 533.5 μmol g−1 h−1 and 94.8%, respectively. Moreover, transient intermediate capture and isotope labeling experiments demonstrate that the oxygen sources of products for this heterojunction are mainly from O2, which contrasts with that from water in pristine BiVO4, owing to the difference in the pathway of O2 reduction induced by the increased thermodynamic driving force. This work provides an effective strategy for the design and development of a cost-effective catalyst system for CH4 conversion in a mild manner. [ABSTRACT FROM AUTHOR]

The well‐known toxicity of lead‐halide‐perovskite (LHP) nanocrystals limits their commercial applications in photocatalysis. Herein, an in situ controlled growth strategy is reported for lead‐free perovskite nanocrystals (Cs3Bi2I9) on the surface of ultrathin Bi2WO6 nanosheets through co‐sharing Bi atoms, to generate a direct Z‐scheme heterojunction of Cs3Bi2I9/Bi2WO6. Co‐sharing of the Bi atom can enable intimate contact and strong electron coupling between Cs3Bi2I9 and Bi2WO6, which can effectively promote the interfacial charge transfer between Cs3Bi2I9 and Bi2WO6 complying with a Z‐scheme pathway. The resulting efficient charge transfer and well‐preserved redox ability of Cs3Bi2I9/Bi2WO6 heterojunction endow it with a significant improvement of photocatalytic activity for the conversion of CO2‐to‐CO integrated with water oxidation, exhibiting a fourfold increase compared with pure Cs3Bi2I9 nanocrystals. This study paves a new avenue for the construction of efficient Z‐scheme heterojunction based on lead‐free halide perovskite, which should stimulate further passion on the development of high performance of lead‐free halide perovskite materials for photocatalytic application. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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/Cs4PbBr6 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. [ABSTRACT FROM AUTHOR]

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 CsPbBr 3 nanocrystals based on a facile microwave synthesis method, and employ it as a photocatalyst for CO 2 reduction. Under the protection of GDY, the CsPbBr 3 -based photocatalyst delivers significantly improved stability in a photocatalytic system containing water concomitant with enhanced CO 2 uptake capacity. The favorable energy offset and close contact between CsPbBr 3 and GDY trigger swift photogenerated electron transfer from CsPbBr 3 to doping metal sites in GDY, boosting a remarkable improvement in the photocatalytic performance for CO 2 reduction. Without adding traditional sacrificial reductants, the cobalt-doped photocatalyst achieves a high yield of 27.7 μmol g -1 h -1 for photocatalytic CO 2 conversion to CO based on water as a desirable electron source, which is about 8 times higher than that of pristine CsPbBr 3 nanocrystals.

A halide perovskite based photocatalyst has been demonstrated for the first time to simultaneously achieve efficient photocatalytic CO 2 reduction and methanol oxidation, exhibiting an exciting yield of 1835 μmol g -1 for photocatalytic CO 2 -to-CO conversion. Moreover, almost stoichiometric value-added formic acid can be produced from methanol oxidation.

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 CO 2 reduction owing to the lack of intrinsic catalytic sites and insufficient charge separation. Herein, we functionalized CsPbBr 3 nanocrystals with graphitic carbon nitride, containing titanium-oxide species (TiO-CN) to develop an efficient composite catalyst system for photocatalytic CO 2 reduction using water as the electron source. Compared to its congener with pristine CsPbBr 3 , the introduction of TiO-CN could not only increase the number of active sites, but also led to a swift interfacial charge separation between CsPbBr 3 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 CO 2 to CO with water as the sacrificial reductant. Over 3-fold and 6-fold higher activities than those of pristine CsPbBr 3 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., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)