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A CO2 bridged photocatalytic interface between a nickel metal–organic framework and ruthenium pyridine for high-efficiency photoreduction of diluted CO2.

Precise synthesis of polyoxometalates (POMs) is important for the fundamental understanding of the relationship between the structure and function of each building motif. However, it is a great challenge to realize the atomic-level tailoring of specific sites in POMs without altering the major framework. Herein, we report the first case of Ce-mediated molecular tailoring on the unprecedented gigantic {Mo132}, which has a closed structural motif involving a never seen {Mo110} decamer. Such capped wheel {Mo132} undergoes a rare quasi-isomerism with known {Mo132} ball displaying different optical behaviors. Experiencing an ‘Inner-On-Outer’ binding process with the substituent of {Mo2} reactive sites in {Mo132}, the site-specific Ce ions drive the dissociation of {Mo2*} clipping sites and finally give rise to a predictable half-closed product {Ce11Mo96}. By virtue of the tailor-made open cavity, the {Ce11Mo96} achieves high proton conduction, nearly two orders of magnitude than that of {Mo132}. This work offers a significant step toward the controllable assembly of POM clusters through a Ce-mediated molecular tailoring process for desirable properties.

This highlight focuses on the strategies to improve the photocatalytic reduction of low-concentration CO2 by MOF materials, including the modification of MOF skeletons and the preparation of MOF composites or MOF derivatives. It will provide insights into the rational design of heterogeneous catalysts to achieve efficient reduction of low-concentration CO2.

A POMOF with [W10O32]4− and mononuclear cobalt clusters as connecting nodes, which can be used as a photocatalyst to reduce low concentrations of CO2 in flue gas to generate syngas.

Photocatalytic carbon dioxide reduction (CO2RR) is considered to be a promising sustainable and clean approach to solve environmental issues. Polyoxometalates (POMs), with advantages in fast, reversible, and stepwise multiple-electron transfer without changing their structures, have been promising catalysts in various redox reactions. However, their performance is often restricted by poor thermal or chemical stability. In this work, two transition-metal-modified vanadoborate clusters, [Co(en)2]6[V12B18O54(OH)6]·17H2O (V12B18-Co) and [Ni(en)2]6[V12B18O54(OH)6]·17H2O (V12B18-Ni), are reported for photocatalytic CO2 reduction. V12B18-Co and V12B18-Ni can preserve their structures to 200 and 250 °C, respectively, and remain stable in polar organic solvents and a wide range of pH solutions. Under visible-light irradiation, CO2 can be converted into syngas and HCOO- with V12B18-Co or V12B18-Ni as catalysts. The total amount of gaseous products and liquid products for V12B18-Co is up to 9.5 and 0.168 mmol g-1 h-1. Comparing with V12B18-Co, the yield of CO for V12B18-Ni declines by 1.8-fold, while that of HCOO- increases by 35%. The AQY of V12B18-Co and V12B18-Ni is 1.1% and 0.93%, respectively. These values are higher than most of the reported POM materials under similar conditions. The density functional theory (DFT) calculations illuminate the active site of CO2RR and the reduction mechanism. This work provides new insights into the design of stable, high-performance, and low-cost photocatalysts for CO2 reduction.

A TPE-based fluorescent porous covalent organic polymer (COP-3) was designed and synthesized. The COP-3 exhibits excellent performance in sensing Fe3+ with high anti-interference, recyclability and a low limit of detection (LOD) of 0.191 μM (10.696 ppb), which is much lower than those of the reported metal-free porous polymers.

Systematic design and self-assembly of metal-organic polyhedra with predictable configuration has been a long-standing challenge in crystal engineering due to the difficulty of finding suitable building units. Herein, we are focused on a concave polyoxovanadate cluster [V6O6(OCH3)9(SO4)4]5- that can be generated in situ under the exact reaction conditions. Based on this cluster, a potential trivalent molecular building block [V6O6(OCH3)9(SO4)(CO2)3]2- can be obtained by the bridging-ligand-substitution strategy that possesses appropriate angle information for the design of molecular cubes. Utilizing the face-directed assembly of the trivalent molecular building block and a diverse set of tetratopic carboxylate linkers, a series of metal-organic cubes VMOC-1 to VMOC-5 with the same topology but different functionalities and dimensions are designed and constructed. The inclusion study made with VMOC-3 as an example has shown that they are potential molecular receptors and can selectively capture size-matching polycyclic aromatic hydrocarbon guest molecules.

For high reactivity but poor stability of homogeneous metal complexes in CO2 photoreduction, development of durable systems is still a big challenge. Herein, pentanuclear Co(II) complex [Co5(btz)6(NO3)4(H2O)4] (1, btz = benzotriazolate) is explored for converting CO2 to syngas which shows high stability and reactivity in both pure and diluted CO2. Compared with mononuclear structure, multinuclear complex exhibits 212-fold enhancement in reactivity, up to ~2748 TONs, with wide adjustability of H2/CO ratio from 16:1 to 2:1. This reactivity could be maintained over 200 h which is an order of magnitude higher than the durability of mononuclear complex and exceeds most reported homogeneous molecular catalysts. High reactivity is also achieved in extreme low CO2 content (5%). Structural analysis and density functional theory (DFT) calculations support that multinuclear structure and the low energy barrier for photocatalytic intermediate may account for the durable and efficient performance of complex 1. The multinuclear strategy is also adopted to nickel complex. This work probes origin of metal-node-dependent performance for CO2 photoreduction, providing new insights in design of durable and efficient metal complexes for photocatalysis and other applications.

The direct usage of CO

At present, the fixation of CO2 always requires it to be extracted from the atmosphere first, which leads to more energy consumption. Thus, direct photoreduction of low-concentration CO2 to useful chemicals (e.g., syngas) under sunlight is significant from an energy-saving and environmentally friendly perspective. Here, the design and fabrication of a [Ru(bpy)3 ]/[Co20 Mo16 P24 ] composite is demonstrated for visible-light-driven syngas production from diluted CO2 (3-20 %) gas with a high yield of approximately 1000 TONs (turnover number of syngas). This activity is an order of magnitude higher than the reported system with [Ru(bpy)3 ]2+ participation. With evidence from ultrafast transient absorption, GC-MS, 1 H NMR spectroscopy and in situ transient photovoltage tests, a clear and fundamental understanding of the highly efficient photoreduction of CO2 by the [Ru(bpy)3 ]/[Co20 Mo16 P24 ] composite is achieved. Making use of the structure and property designable polyoxometalates towards the photo-fixation of CO2 is a conceptually distinct and commercially interesting strategy for making useful chemicals and environmental protection.

Light irradiation can affect electronic properties of catalysts and the introduction of appropriate light into electrocatalysts may have a significant impact on the electrocatalytic process; however, this has not been fully studied. Herein, we propose a photo-activated process cascaded electrocatalysis for CO2 reduction to produce syngas over a core–shell ZIF-8@Co/C catalyst. Under light irradiation, the onset potential and overpotential of ZIF-8@Co/C positively shift by 40 and 200 mV, and the syngas production is enhanced 5.2-fold at a bias potential of −0.9 V vs. RHE. It is noteworthy that the electric energy efficiency is enhanced by 30%. Deducting syngas generated by electricity, the solar-to-syngas conversion efficiency (joule to joule) is as high as 5.38%, which outperforms reported photoelectrochemical systems. These devices also relatively maintain high efficiency in neutral pH aqueous solution. Dedicated experiments and in situ transient photovoltage studies demonstrate that the cascaded photo-activation of CO2 and H+ in electrocatalysis accounts for the outstanding catalytic performance.

Direct CO2 conversion from flue gas into high-value products is of great significance not only in relieving environmental burden but alleviating the energy crisis by a low-cost and energy-saving avenue, yet few studies in this aspect have been reported. Herein, we report metal-node-dependent catalytic performance for solar-energy-powered CO2 reduction to formate in simulated flue gas by bimetallic Ni/Mg-MOF-74. The yield of HCOO− with Ni0.75Mg0.25-MOF-74 as a catalyst in pure CO2 is 0.64 mmol h−1 gMOF−1 which is higher than that of Ni-MOF-74 (0.29 mmol h−1 gMOF−1) and Ni0.87Mg0.13-MOF-74 (0.54 mmol h−1 gMOF−1), whereas monometallic Mg-MOF-74 is almost inactive, indicating that reactivity relies on metal nodes. In simulated flue gas without water vapor at 20 °C, ∼80% of the reactivity in pure CO2 is retained, with HCOO− generation reaching 0.52 mmol h−1 gMOF−1. This activity is comparable to that of the best MOF catalysts in pure CO2, demonstrating that Ni/Mg-MOF-74 not only overcomes the limitation from CO2 concentration, but also has good resistance to other gas components in flue gas at 20 °C. DFT calculations reveal the high output for HCOO− from two crucial factors: strong CO2 binding affinity of Mg sites, and the synergistic effect of Mg and Ni leading to the stabilization of the key *OCOH intermediate with an appropriate energy barrier. This work paves a new route for double-metal MOFs to enhance the CO2 photoreduction reactivity in flue gas.

We prepare a novel COF for CO2 photoreduction with 99.9% CO selectivity in aqueous solution without a cocatalyst. DFT shows that the preferential adsorption of H+ on the COF results in increased CO2 adsorption energy providing an anchoring site of CO2, and with the cooperation of an ethylene group, CO2 reduction is triggered.

Three nanosized zirconium-based molecular capsules (Zr-MCs) constructed from trinuclear zirconocene building blocks and linear carboxylate ligands, namely, {[Cp3Zr3(μ3-O)(μ2-OH)3]2(BDC)3}·Cl2(DMA)(H2O) (Zr-MC-1), {[Cp3Zr3(μ3-O)(μ2-OH)3]2(SDC)3}·Cl2(DMF)2.5 (Zr-MC-2), and {[Cp3Zr3(μ3-O)(μ2-OH)3]2(ADA)3}·Cl2(DMF)2 (Zr-MC-3) (H2BDC = 1,4-benzenedicarboxylic acid; H2SDC = 4,4-stilbenedicarboxylic acid; H2ADA = azobenzene-4,4-dicarboxylic acid), have been synthesized under solvothermal conditions and characterized by single-crystal X-ray diffraction, elemental analysis, powder X-ray diffraction, IR spectroscopy, and thermogravimetric analysis. Additionally, Zr-MC-2 can serve as a promising selective sensor for Fe3+. Meanwhile, the absorption ability of Zr-MC-1 and Zr-MC-3 toward iodine was investigated.

A novel porous triazine-based metal-organic framework, ([Cd (Ligand)]∙2DMF) (1) with strong luminescence, has been constructed via multi-carboxyl ligand 5,5′,5''-((1,3,5-triazine-2,4,6-triyl)tris(azanediyl))tris(3-methylbenzoic acid) under solvothermal conditions. Structural analysis revealed that MOF1 has a three-dimensional (3D) framework which is crystallized in the monoclinic system bearingC2/c space group. The high chemical and thermal stability of synthesized MOF1 has been predicted by powder X-ray diffraction and thermogravimetric analysis techniques. Higher selectivity and sensitivity of MOF1 towards Cu2+ions is remarkable with an adsorption capacity of 90.5 mg/g compared with Mg2+, Mn2+, Ni2+, Co2+, Zn2+, Fe2+ and Cr3+ ions. Results reveal that strong emission of MOF1 can be quenched effectively by a trace amount of copper (3 ppm) and nitrobenzene (0.6 ppm), even in the vapor phase. The extraordinary solvatochromic phenomenon of MOF1 is observed by incorporating acetonitrile guest molecules due to host-guest interactions provided by the carboxyl groups of ligand and imino triazine backbone. Thus, owing to the highly selective and sensitive quenching effect in fluorescence and solvatochromic behavior, MOF1 can be used as a potential sensor for Cu2+, NB, and acetonitrile.

The synthesis of ultra-stable chiral porous organic cages (POCs) and their controllable chiral self-sorting at the molecular and supramolecular level is still a daunting challenge. Herein, we report the design and synthesis of a serial of axially chiral porous aromatic cages (1-S and 1-R) with exceptional chemical stability. The theoretical and experimental studies on chiral self-sorting reveal that the exclusive self-recognition on cage formation is an enthalpy-driven process while the chiral narcissistic and social self-sorting on supramolecular assembly of racemic cages can be precisely regulated by π–π and C–H…π interactions from different solvents. Moreover, the crystallinity of 1 can be preserved under various harsh conditions including boiling water, and high-concentrated acid and alkali solutions. Further investigations on chiral sensing show that 1 possesses high enantioselectivity toward axially chiral aromatic racemates.

Photocatalytic carbon dioxide reduction (CO

The rational design and construction of multifunctional electrocatalysts with high activity, low cost, and outstanding stability are highly desirable for the development of renewable energy but are still a big challenge. Bimetallic catalysts are a kind of promising candidates, like the hybrids of Co and VN nanoparticles (Co/VN). However, the inevitable aggregation during the preparation and electrochemical process lowers their reactivity and durability. Herein, small Co/VN nanoparticles (4-8 nm) embedded in porous graphitic carbon layers (Co/VN NPs@C) were obtained through the pyrolysis of metal-organic frameworks (MOFs). The synergistic effect of in situ generated Co and VN NPs together with fast electron transfer from graphitic carbon layers renders this catalyst to possess excellent trifunctional performance. More attractively, Co/VN NPs@C as both the anode and the cathode shows a low voltage of 1.58 V when the current density is up to 10 mA cm-2, exceeding most electrocatalysts based on non-noble metals. The rechargeable Zn-air batteries constructed by Co/VN NPs@C deliver high round-trip efficiency together with a peak power density of 130 mW cm-2, a specific capacity of 757 mAh g-1, and desirable stability, outperforming the traditional Zn-air batteries based on the Pt/C and RuO2 pair. This work opens a promising avenue toward constructing highly effective multifunctional electrocatalysts by designing small-sized nanoparticles with various active sites derived from MOFs.

The mercury ions in waste water have threatened public health and environmental protection. In this sense, novel materials with outstanding performances for removal of Hg

Inspired by the structures of virus capsids, chemists have long pursued the synthesis of their artificial molecular counterparts through self–assembly. Building nanoscale hierarchical structures to simulate double-shell virus capsids is believed to be a daunting challenge in supramolecular chemistry. Here, we report a double-shell cage wherein two independent metal–organic polyhedra featuring Platonic and Archimedean solids are nested together. The inner (3.2 nm) and outer (3.3 nm) shells do not follow the traditional “small vs. large” pattern, but are basically of the same size. Furthermore, the assembly of the inner and outer shells is based on supramolecular recognition, a behavior analogous to the assembly principle found in double-shell viruses. These two unique nested characteristics provide a new model for Matryoshka–type assemblies. The inner cage can be isolated individually and proves to be a potential molecular receptor to selectively trap guest molecules., Supramolecular constructs that mimic complex biological assemblies are synthetically challenging. Here, the authors present a double-shell cage wherein two independent metal-organic polyhedra are nested together in a manner analogous to that found in double-shell virus capsids.

We prepare a novel COF for CO2 photoreduction with 99.9% CO selectivity in aqueous solution without a cocatalyst. DFT shows that the preferential adsorption of H+ on the COF results in increased CO2 adsorption energy providing an anchoring site of CO2, and with the cooperation of an ethylene group, CO2 reduction is triggered.

Metal-organic polyhedra (MOPs) are promising candidates for many potential applications; however, their use as photocatalysts for hydrogen production has yet to be developed. Herein, the photocatalytic performance of a water-stable Zr-MOP, ZrT-1-NH2 , was evaluated, for the first time, through photocatalytic hydrogen evolution under visible-light irradiation. ZrT-1-NH2 shows clearly enhanced photocatalytic activity (510.42 μmol g-1 h-1 ) for hydrogen production, in comparison with that of other homogeneous crystalline materials. If platinum nanoparticles were introduced into the photocatalytic system, the hydrogen production efficiency of ZrT-1-NH2 could be further improved. For ZrT-1-NH2 , the conspicuous improvement in photocatalysis can be attributed to efficient electron-hole separation, targeted electron transfer, and excellent recombination suppression. Furthermore, ZrT-1-NH2 shows excellent stability during photocatalytic hydrogen evolution over five continuous runs. This work illustrates that MOP-based photocatalysts hold promise for broad applications in the domain of clean energy.

The photoreduction of carbon dioxide (CO2) into a valuable energy gas (CO and H2) is an efficient approach to address the fossil fuel crisis and mitigate the global warming effect. The development of effective photocatalysts for CO2 reduction is still desirable and challenging. Herein, two novel polyoxometalate-based hybrids with multinuclear cobalt clusters, [Co2.67(SiW12O40)(H2O)4(Htrz)4]·Cl1.33 (Htrz = 1,2,4-triazole) (1) with a binuclear cobalt cluster and [Co3(SiW12O40)(H2O)3(Htrz)6Cl]·Cl·6H2O (2) with a trinuclear cobalt cluster, were synthesized under hydrothermal conditions. Both of them were characterized by single-crystal X-ray diffractions, PXRD, IR, TG and UV–vis spectra. Compound 1 exhibited a 3D structure with 4-connected [SiW12O40] and 3-connected [Co2(Htrz)3(H2O)3] secondary building units (SBUs). The 1D chain of compound 2 was constructed from [SiW12O40] and [Co3(Htrz)6(H2O)3Cl] SBUs. Furthermore, the photoreduction of CO2 under visible light by the two cobalt-based POMs was investigated using [Ru(bpy)3]Cl2·6H2O as a photosensitizer. The CO yields of compounds 1 and 2 were 15 705 and 18 501 μmol g−1 for the CO2 photocatalytic reduction under three hour irradiation at 293 K, respectively. The difference in the photocatalytic performance of 1 and 2 was explained by comparing the energy of the valence band, band gaps and conduction band. The results showed that the photocatalysts incorporated with multinuclear Co clusters could effectively improve photocatalytic activities, thus providing a valuable view to design high performance and cost-acceptable molecular catalysts for CO2 photoreduction.

CsPbBr3 is widely used in solar cells and LEDs for its excellent photoelectric properties that are also attractive for CO2 photoreduction, but it is less used in the photocatalytic reduction of CO2 mainly owing to its limited charge separation efficiency. To alleviate this issue, herein, all-inorganic orthorhombic CsPbBr3 was combined with graphitic carbon nitride (g-C3N4) and the resultant composite (CsPbBr3@g-C3N4) showed enhanced activity in CO2 photoreduction. Under the irradiation of AM1.5 filter for 12 h, CO2 was converted into CH4 and CO with high selectivity to methane (91%) and the total amount of gaseous products up to ∼300 μmol g-1. This reactivity is 6-fold and 4-fold higher than that of pure g-C3N4 and CsPbBr3, respectively. CsPbBr3@g-C3N4 also shows excellent catalytic activity at low concentrations of CO2. Studies of energy band level and steady-state and transient photoluminescence spectroscopy indicated that the incorporation of CsPbBr3 and g-C3N4 increases charge separation, which may result in sharply enhanced catalytic efficiency. This study has provided opportunities for the combination of CsPbBr3 and other semiconductor catalysts for the photocatalytic reduction of CO2.

Development of efficient, selective and low-cost photocatalysts, ideally constructed from Earth-abundant elements, is still a big challenge for CO2 photoreduction. Herein, adopting mixed halides strategy, the activity of all-inorganic perovskites toward CO2 reduction is enhanced sharply under simulated sunlight without photosensitizer, meanwhile maintaining high selectivity of CO and CH4 production. Via regulating ratio of Br and Cl, the yield of CO and CH4 changes obviously and the optimized catalyst is CsPb(Br0.5/Cl0.5)3 with a total yield of CO and CH4 up to 875 μmol/g (selectivity of 99%) which outperforms any other reported halide perovskites and is 4.5 and 9.1 folds higher than that of CsPbBr3 and CsPbCl3 under the same condition. The efficient charge separation and moderate stability in mixed-halide perovskites may account for the excellent performance in CO2 reduction. This study may provide a new strategy in design of high performance and low-cost halide perovskite materials for photocatalysis.

In this study, a triazine-based nanoporous metal–organic framework (MOF1) using the tricarboxyl ligand 5,5′,5′′-((1,3,5-triazine-2,4,6-triyl)tris(azanediyl))tris(2-methylbenzoic acid) was solvothermally synthesized. High thermal and chemical stability of MOF1 was established by thermogravimetric and powder X-ray diffraction analysis. Owing to its porous structure with potential nitrogen chelating sites, MOF1 could selectively adsorb the Cu2+ ions over the Mn2+, Ni2+, Co2+, and Zn2+ ions, and the chromatographic separation of the Co2+ ion was achieved from a mixed solution containing Co2+ and Cu2+. Moreover, MOF1 could selectively adsorb and separate cationic dyes on the basis of ionic selectivity rather than size selectivity. Furthermore, the nanoporous MOF1 was used as a host to encapsulate luminescent species, and it displayed a characteristic luminescent color (green for Tb3+ and red for Eu3+); moreover, we tuned the luminescence properties of the MOF1 to achieve white light emission with good color quality.

A newly prepared tetraphenylethylene-based (TPE-based) covalent organic polymer (COP) named COP-1 exhibits high selectivity for sensing Fe3+ and the limit of detection (LOD) for Fe3+ is 0.42 μM, which is lower than the reported metal-free porous polymers. Furthermore, a WLED is fabricated and the CIE coordinates are (0.32, 0.33), very close to pure white light. The COP-1 shows potential applications in biosensors of Fe3+ and preparation of WLEDs.

A system containing polyoxometalate ([Co-POM]

A rational synthetic strategy to construct two supramolecular isomers based on polyoxovanadate organic polyhedra with tetrahedral symmetries is presented. VMOP-α, a low-temperature product, has an extremely large cell volume (470 842 A3 ), which is one of the top three for well-defined MOPs. The corner-to-corner packing of tetrahedra leads to a quite low density of 0.174 g cm-3 with 1D channels (ca. 5.4 nm). The effective pore volume is up to 93.6 % of cell volume, nearly the largest found in MOPs. For the high-temperature outcome, VMOP-β, the cell volume is only 15 513 A3 . The packing mode of tetrahedra is corner-to-face, giving rise to a high-density architecture (1.324 g cm-3 ; channel 0.8 nm). Supramolecular structural transformation between VMOP-α and VMOP-β can be reversibly achieved by temperature-induced solvent-mediated transformation. These findings give a good opportunity for understanding 3D supramolecular aggregation and crystal growth based on large molecular tectonics.

As the main component of syngas, reducing CO2 to CO with high selectivity through photocatalysis could provide a sustainable way to alleviate energy shortage issues. Developing a photocatalytic system with low cost and high performance that is environmentally friendly is the ultimate goal towards CO2 photoreduction. Herein, an efficient and economic three-component heterojunction photocatalyst is designed and fabricated for converting CO2 to CO in the absence of organic sacrificial agents. The heterojunction is made of Cu2-x S nanotubes coated with a carbon layer (C-Cu2-x S) and g-C3 N4 . By using the classical MOF material HKUST-1 as a precursor, hollow tubular-like metal sulfides (C-Cu2-x S) with carbon coating were synthesized and further loaded on g-C3 N4 , forming a three-component heterojunction C-Cu2-x S@g-C3 N4 . The carbon coat in C-Cu2-x S@g-C3 N4 acts as an electron reservoir, which facilitates electron-hole pair separation. The optimized C-Cu2-x S@g-C3 N4 acted as a photocatalyst in CO2 reduction with a high reactivity of 1062.6 μmol g-1 and selectivity of 97 %. Compared with bare g-C3 N4 (158.4 μmol g-1 ) and C-Cu2-x S, the reactivity is nearly 7 and 23-fold enhanced and this CO generation rate is higher than most of the reported Cu2 S or g-C3 N4 composites under similar conditions. The prominent activity may result from enhanced light adsorption and effective charge separation. This work might open up an alternative method for the design and fabrication of high-performance and low-cost photocatalysts for efficiently and durably converting CO2 to CO with high selectivity.

A novel porous coordination polymer compound [Cd0.5(tpy)]∙0.75H2O was prepared by hydrothermal synthesis, which exhibits excellent chemical stability under various organic solvents and aqueous solution with different pH values range from 3 to 13. Benefiting from guest water molecules existing in the crystal structure, this compound shows water-mediated proton (H+) ion-conducting with conductivity of 6.03 × 10−6 S·cm−1 under 97% relative humidity at 95 °C. The calculated thermal activation energy (1.09 eV) and strong dependency on the humidity indicates a vehicle mechanism in the proton conduction process.

Luminescent organogold(III) complex AuIII with highly emissive triplet excited state was encapsulated in two metal-organic frameworks (MOFs) with different pore sizes and structures (MOF1 and ZJU-28). Compared with the AuIII complex in solution, the resultant composites AuIII @MOF1 and AuIII @ZJU-28 exhibit enhanced emission intensity, lifetime, and quantum yield. Under irradiation, AuIII @MOFs are efficient, selective, and recyclable catalysts for light-induced aerobic C-N bond formation. When used as a heterogeneous catalyst for oxidizing secondary amines to the corresponding imines, AuIII @ZJU-28 achieved high TONs of 876-1548, which are about 2.8-3.5 times higher than that of the homogenous AuIII complex. In addition, different selectivities in oxidizing mixed substrates is realized by means of different host MOFs, and thus encapsulating the AuIII complex in an appropriate MOF allowed the desired product to be obtained. Inherent shortcomings of homogeneous catalysts in cyclic use are also overcome by using composite catalysts, and high conversion of the AuIII @ZJU-28 catalyst was still observed after ten cycles.

Herein, we reported a pair of di-nuclear europium enantiomers [Eu2(PO4)6(R-/S-HL)6(MeOH)4]•2MeOH (R-complex(1a) and S-complex(1b)) constructed from chiral ligands (R)-/(S)-(+)-1,1′-binaphthyl-2,2′-diyl hydrogenphosphate (R-/S-HL) and europium (III) nitrate by solvothermal method. The structure of the complexes was characterized by single-crystal X-ray diffraction, powder X-ray diffraction and Fourier transform infrared spectroscopy. It was found that R-complex(1a) and S-complex(1b) were chiral enantiomers with a zero-dimensional chiral cluster structure. The circular dichroism studies further revealed the chiral properties of R-complex(1a) and S-complex(1b). Moreover, fluorescence sensing tests demonstrated that R-complex(1a) and S-complex(1b) possessed high enantioselectivity for axially chiral BINOL racemates.

To explore cost-efficient, highly active and robust bifunctional electrocatalysts for overall water splitting, both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), is of much significance for renewable-energy systems but remains challenging as well. Herein, we report two multicomponent heterostructures as efficient bifunctional electrocatalysts, Co2P/Mo2C/Mo3Co3C and Ni/Ni2P/Mo2C nanoparticles encapsulated in porous graphene shells (termed Co2P/Mo2C/Mo3Co3C@C and Ni/Ni2P/Mo2C@C). Two bimetallic MOFs (CoMo-MOF and NiMo-MOF) with ordered heterogeneity were used as precursors to synthesize Co2P/Mo2C/Mo3Co3C@C and Ni/Ni2P/Mo2C@Cvia a facile and versatile two-step method and a direct carbonization process followed by phosphorization. The resultant catalysts manifest superior HER performance with low overpotentials of 154 and 183 mV delivering a current density of 10 mA cm−2 in acidic media. More importantly, both Co2P/Mo2C/Mo3Co3C@C and Ni/Ni2P/Mo2C@C exhibit favorable HER and OER activity under alkaline conditions. Remarkably, Co2P/Mo2C/Mo3Co3C@C affords overpotentials of 182 mV and 362 mV at 10 mA cm−2 for the HER and OER. Moreover, the two catalysts present good stability in both acidic and basic electrolytes. The synergistic effect of the multicomponent electrochemically active species and the uniform distribution, mesoporous structures and carbon coating are beneficial for the charge transfer during the catalytic process, which results in excellent performance, comparable to many reported nonprecious electrocatalysts. Furthermore, Co2P/Mo2C/Mo3Co3C@C catalysts were exploited as both the anode and cathode in a home-made electrolyser with alkaline electrolyte, which can afford 10 mA cm−2 at a cell voltage of 1.74 V.

Pincer platinum(II) complexes are well documented to exhibit weak intermolecular interactions in the solid state and 77 K glassy solutions, leading to emissive triplet metal–metal-to-ligand charge transfer (3MMLCT) excited states that often vanish in dilute solutions. In this work, metal–organic framework (MOF) materials are introduced to provide a “solid solution” environment for easy access to 3MMLCT excited states of pincer platinum(II) complexes. Phosphorescent composites PtII@MOFs (1–4) with matrix-dependent monomers and oligomer emission properties were obtained. These PtII@MOFs are efficient catalysts for photoinduced dehydrogenation reactions.

The photoreduction of CO2 to CO offers a promising sustainable and clean approach for a global new energy program. Coupling this reductive process with a matched water photo-oxidation pathway is an attractive avenue to accelerate the half-reaction of CO2 reduction. Herein, we propose a three-component photocatalyst design strategy for reducing CO2 to CO coupled with water oxidation via a two-electron/two-step pathway. Employing polyoxotitanium ([Ti17O24(OPri)20]) as a titanium source, ultrasmall TiO2−x nanoparticles coated with ultrathin carbon layers (C-TiO2−x) were fabricated and loaded on to a g-C3N4 matrix through chemical bonding (C-TiO2−x@g-C3N4) for the first time. The optimized C-TiO2−x@g-C3N4 photocatalyst showed a very high activity of 12.30 mmol g−1 (204.96 mmol gTiO2−1) CO generation within 60 h visible-light irradiation, which represents the highest CO production rate to date among the reported TiO2-based materials under similar conditions. The excellent adsorption capability of C-TiO2−x@g-C3N4 for photons, H+ protons, and CO2 molecules together with efficient charge separation and the two-electron/two-step oxidative pathway lead to the high reactivity.

As is well known, carbon dioxide (CO2) reduction reaction (CO2 RR) by photocatalytic technology is a means with great promise to alleviate the crises on the global energy and the environmental fronts. It is critical to design and construct photocatalysts with high performance as catalysts are the core of the photocatalytic process. Recently, polyoxometalates (POMs) have aroused wide research interest as CO 2 photoreduction-related catalysts because they possess tunable compositions, thermal stability, redox reaction and tailorable light-absorption capabilities. This review has discussed the recent progress of POMs and POM-based photocatalysts for CO 2 reduction focusing on the roles of POMs as photocatalysts, cocatalysts, photocatalytic hosts (photosensitizers), and multi-electron donors in systems of CO2 photoreduction, which can provide important guides for the design of high-efficiency photocatalysts. In the end, based on summarizing the previous work, we make a prospect to the future research direction, key challenges, and possible solutions in this field.

A novel metal-organic framework (MOF) with a π-conjugated porous condition is reported to sensor fused aromatic hydrocarbons molecules. This MOF assembled by N-heterocyclic multi-carboxyl ligands and Cd ions shows hexagonal hydrophobic channels along [100] and [010] directions with size 18.4 × 15.5 A2. Under the excitation of 338 nm, this MOF emits blue light peaking at 397 nm. Under immersing this MOF in the solutions containing aromatic hydrocarbon, including naphthalene, anthracene and phenanthrene within different time, the luminescent intensity of MOF enhanced different degree upon encapsulating aromatic hydrocarbons guest molecules. Therefore, this material shows favourable property of recognition for aromatic hydrocarbons molecules via solid-state photoluminescence.

Developing a photocatalysis system for converting CO2 to valuable fuels or chemicals is a promising strategy to address global warming and fossil fuel consumption. Exploring photocatalysts with high-performance and low-cost has been two ultimate goals toward photoreduction of CO2. Herein, noble-metal-free polyoxometalates (Co4) with oxidative ability was first introduced into g-C3N4 resulted in inexpensive hybrid materials (Co4@g-C3N4) with staggered band alignment. The staggered composited materials show a higher activity of CO2 reduction than bare g-C3N4. An optimized Co4@g-C3N4 hybrid sample exhibited a high yield (107 μmol g–1 h–1) under visible-light irradiation (λ ≥ 420 nm), meanwhile maintaining high selectivity for CO production (94%). After 10 h of irradiation, the production of CO reached 896 μmol g–1. Mechanistic studies revealed the introduction of Co4 not only facilitate the charge transfer of g-C3N4 but greatly increased the surface catalytic oxidative ability. This work creatively combined ...

We synthesized a novel MOF with an sqc1575 topology as an ideal host matrix that exhibits luminescence energy transfer with polycyclic aromatic hydrocarbons (PAHs). What's more, the PAHs@MOF composites display an interesting quenching behavior in the presence of the electron donor triethanolamine (TEOA). We report for the first time that the well-defined porosity of a luminescent MOF enables it to serve as a host matrix for encapsulating chromophoric PAH molecules to modulate luminescence properties, and further exploit its reductive quenching properties by using a photocatalytic sacrificial electron donor.

Halide perovskites have been employed as photocatalysts for CO

Covalent organic polymers (COPs) received much attention due to their application in diverse fields, especially in sensing. A highly efficient fluorescence sensor in selective detection of Fe3+ions is necessary to develop. In this work, we successfully synthesized a new covalent organic polymers named COP-TP, with the excellent performance in selective detection of Fe3+ions, the quenching mechanism mainly due to the energy transfer process. The above results show COP-TP has the possibility to be a new candidate in selective detection as Fe3+ions sensor.

A newly prepared tetraphenylethylene-based (TPE-based) covalent organic polymer (COP) named COP-1 exhibits high selectivity for sensing Fe3+ and the limit of detection (LOD) for Fe3+ is 0.42 μM, which is lower than the reported metal-free porous polymers. Furthermore, a WLED is fabricated and the CIE coordinates are (0.32, 0.33), very close to pure white light. The COP-1 shows potential applications in biosensors of Fe3+ and preparation of WLEDs.

Newfangled frangipani-like [MV5O6(μ3-O)5(SO4)(COO)5] (M = Nb/W) polyanions served as 5-connected molecular building blocks (MBBs) that simultaneously assembled with 4-connected [V5O9Cl] MBBs and tricarboxylate ligands (H3BTC) to form two new polyoxovanadate-based metal–organic polyhedra {[MV5O6(μ3-O)5(SO4)]4[V5O9Cl]4(BTC)12} with undiscovered “near-miss Johnson solid” geometry. Moreover, the variable-temperature magnetic susceptibilities were investigated.