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In the field of recycling CO2, the photocatalytic CO2reduction reaction (CO2RR) is a typical example, and researchers have designed a variety of photocatalysts to improve the conversion rate of CO2over the years. In this paper, two metal–oxygen clusters are designed and formulated as [Co3Zn(OH)6(SO4)]·4H2O (1) and [Ni3Zn(OH)6(SO4)]·4H2O (2). As for compound 1, the main structure is composed of {CoO6} octahedra connected by edge-sharing to form a two-dimensional layer, on which {ZnO4} and {SO4} tetrahedra are supported. More interestingly, compound 1has outstanding photocatalytic activity, which is mainly attributed to the open-framework structure and the cobalt ions as active sites. Upon catalysis for eight hours, its maximum CO generation rate is 9982.13 μmol g–1h–1, with a selectivity of 81.8%. Additionally, compound 1takes on weak antiferromagnetic coupling due to Co(II) ions.

The self-assembly of the high-nuclearity Ln-exclusive nanoclusters is challenging but of significance due to its aesthetically pleasing architectures and far-reaching latent applications in magnetic cooling technologies. Herein, two novel high-nuclearity lanthanide nanoclusters were successfully synthesized under solvothermal conditions, formulated as {[Gd18(IN)20(HCOO)8(μ6-O)(μ3-OH)24(H2O)4]·4H2O}nand {[Eu18(IN)16(HCOO)8(CH3COO)4(μ6-O)(μ3-OH)24(H2O)4]·5H2O}n(abbreviated as Gd18and Eu18, HIN = isonicotinic acid). Both of them possess novel and exquisite windmill-shaped cationic cores in the family of high-nuclearity Ln-exclusive nanoclusters. Remarkably, the adjacent second building units are interconnected into a three-dimensional (3D) metal–organic framework by IN–ligands. As expected, the abundant existence of GdIIIions endows Gd18with a favorable magnetic entropy change at 2.0 K for ΔH= 7.0 T (−ΔSmmax= 40.0 J kg–1K–1), and Eu18displays the typical luminescence of EuIIIions.

Sulfur oxides from the combustion of petrol and excessive emissions of carbon dioxide (CO2) are currently the main causes of environmental pollution. Considerable interest has been paid to solving the challenge, and catalytic reactions seem to be the desired choice. Due to the high density of Lewis acid active sites, polyoxometalates are considered to be the ideal choice for these catalytic reactions. Herein, two captivating polyoxometalate-based metal–organic complexes, formulated as [Co(H2O)2DABT]2[CrMo6(OH)5O19] ({Co-CrMo6}) and [Zn(H2O)2DABT]2[CrMo6(OH)5O19] ({Zn-CrMo6}) (DABT = 3,3′-diamino-5,5′-bis(1H-1,2,4-triazole)) were successfully obtained under hydrothermal conditions. The structural analysis demonstrates that {Co-CrMo6}and {Zn-CrMo6}are isostructural with two different transition metal (Co/Zn) ions based on quadridentate Anderson-type [CrMo6(OH)5O19]4–polyanions. A fan-shaped unit of {Co-CrMo6}/{Zn-CrMo6}is linked to generate a one-dimensional (1D) ladder-like structure. Intriguingly, benefitting from rich Co centers with a suitable energy band structure, {Co-CrMo6}displays better photocatalytic activity than {Zn-CrMo6}for converting CO2into CO, endowing the CO formation of 1935.3 μmol g–1h–1with high selectivity. Meanwhile, {Co-CrMo6}also exhibits a satisfactory removal rate of 99% for oxidizing dibenzothiophene at 50 °C, which suggests that {Co-CrMo6}may be utilized as a potential dual functional material with immense prospects in photocatalytic CO2reduction and sulfur oxidation for the first time.

Producing ammonia (NH3) by electrocatalytic N2fixation is a promising and environmentally friendly strategy, in comparison to the Haber–Bosch process with high consumption of energy and CO2emissions. Because of the extremely high bond energy, it is indispensable to explore valid catalysts to activate the triple bond. In this paper, Cr-doped CeO2nanorods are developed to serve as non-noble-metal electrocatalysts for an electrocatalytic N2reduction reaction. Introducing Cr into the catalyst leads to an increase of the oxygen vacancies. In a 0.1 M Na2SO4solution, the Cr0.1CeO2nanorods achieve a high Faradaic efficiency (3.84%) and a large NH3yield (16.82 μg h–1mgcat.–1) at −0.7 V versus reversible hydrogen electrode. The Cr0.1CeO2nanorods also exhibit high stability during the reaction.

Electrochemical reduction is an eco-friendly alternative for energy-saving artificial N2fixation. The development of this process requires efficient N2reduction reaction (NRR) electrocatalysts to overcome the challenge with N2activation. We show that a Cr2O3nanoparticle-reduced graphene oxide hybrid (Cr2O3-rGO) is as an outstanding catalyst for electrochemical N2-to-NH3conversion under ambient conditions. In 0.1 M HCl, Cr2O3-rGO achieves a high NH3yield of 33.3 μg h–1mg–1cat.at −0.7 V vs RHE and a high Faradaic efficiency of 7.33% at −0.6 V vs RHE, with excellent selectivity for NH3synthesis and stability. Density functional theory calculations were executed to gain further insight into the mechanisms.

Electrochemical reduction has been regarded as a sustainable strategy to tackle energy-intensive operations by the Haber–Bosch process achieving catalytic conversion of N2to NH3under mild conditions. However, the challenge of N2electroconversion emphasizes the requirement of efficient electrocatalysts. In this paper, we report the development of porous bromide-derived Ag film (BD-Ag/AF) as an efficient electrocatalyst for N2reduction reaction. During electrochemical test, Br–anions are released and adsorbed onto the surfaces of the electrode, suppressing hydrogen evolution reaction. Such BD-Ag/AF shows a high Faradaic efficiency of 7.36% at −0.6 V vs reversible hydrogen electrode in 0.1 M Na2SO4, which is higher than that (0.38%) of porous Ag film without Br–anions. Moreover, it exhibits excellent long-term electrochemical durability.

The self-assembly of the lanthanide metal–organic frameworks presents a formidable challenge but profound significance. Compared with the metal–organic frameworks based on 4f–3d ions, the chemistry of 4f–3p metal–organic frameworks has not been fully explored so far. In this study, two lanthanide–aluminum-based clusters [Ln6Al(IN)10(μ3–OH)5(μ3-O)3(H2O)8]·xH2O (x= 2, Ln = Gd, abbreviated as Gd6Al; x= 2.5, Ln = Eu, abbreviated as Eu6Al; HIN = isonicotinic acid) have been meticulously designed and obtained by hydrothermal reaction at low pH. The crystallographic study revealed that both Gd6Aland Eu6Alclusters exhibit an unprecedented sandwiched metal–organic framework holding a highly ordered honeycomb network. To our knowledge, it is the first case of Ln–Al-based cluster-organic frameworks. Furthermore, magnetic investigation of Gd6Almanifests a decent magnetic entropy change of −ΔSmmax= 28.8 J kg–1K–1at 2 K for ΔH= 7.0 T. Significantly, the introduction of AlIIIions into the lanthanide metal–organic frameworks displays excellent solid-state luminescent capability with a lifetime of 371.6 μs and quantum yield of 6.64%. The construction and investigation of these two Ln–Al clusters represent great progress in the 4f–3p metal–organic framework.