Zirconium terephthalate UiO-66 has aroused great interest in catalysis since it exhibits significant flexibility and compatibility for accommodating a high number of defects as well as exceptional thermal and chemical stability. Until now, many works have focused on the modulations of the Zr₆-oxo clusters in UiO-66 in terms of diverse synthesis, advanced characterizations, and their catalytic applications. To achieve high catalytic efficiency, it is still highly desired for rationally constructing and modulating the Zr₆-oxo clusters with exposed catalytic sites and diverse microenvironments for advanced catalysis. In this review, we provide a comprehensive summary of recent progress on the synthesis of defective UiO-66, qualitative and quantitative characterizations as well as a logical overview of heterogeneous catalytic applications over the past few years. Finally, the outlooks for the research paradigm of defective UiO-66 are discussed.

Photocatalytic methane conversion to high value-added chemicals under mild conditions acts as a promising approach to utilize natural gas and renewable energy. Specifically, aerobic photocatalytic methane conversion that uses molecular oxygen as oxidant has attracted much attention because it is thermodynamic favorable and could generate various reactive oxygen species, resulting in many value-added products like methanol, formaldehyde, ethane, and ethylene. In this review, we classify the aerobic photocatalytic methane conversion into aerobic photocatalytic partial oxidation of methane (APPOM) and aerobic photocatalytic coupling of methane (APCM). We particularly focus on the fundamentals of oxygen activation and methane reaction modes in these conversions. Finally, we provide a brief summary for current challenges and future prospects towards aerobic photocatalytic methane conversion.

As one of the most promising CO₂ utilization techniques, electrochemical CO₂ reduction has recently received considerable attention. Cu is a unique electrocatalyst that can convert CO₂ to value-added multi-carbon chemicals. Nevertheless, Cu catalysts are always limited by the poor selectivity and stability. Here, we report that using copper-tetracyanoquinodimethane (CuTCNQ) derived Cu nanoparticles as efficient electrocatalysts for conversion of CO₂ to ethylene characteristic with high selectivity and stability, showing 56% Faradaic efficiency (FE) to C₂H₄ at −1.3 V vs. reversible hydrogen electrode (RHE). Upon the electrochemical CO₂ reduction, CuTCNQ slowly reconstructs to Cu nanoparticles with abundant grain boundaries and residual Cu⁺ on the surface. Theoretical calculation and operando characterization disclose that both as-formed Cu nanoparticle grain boundaries and residual Cu⁺ endow the catalyst with high selectivity toward ethylene. Furthermore, during the reconstruction of CuTCNQ to Cu nanoparticles, the grain boundaries Cu surface is slowly refreshed by continual addition of Cu atoms, thus inhibiting the surface passivation and guaranteeing the electrocatalytic stability.

Photocatalysis, via conversion of light into valuable chemicals, is an economic and effective way to utilize inexhaustible solar energy for the sustainable development of our human society. Aiming at killing two birds with one stone, metal nanoparticle (MNP)/metal-organic framework (MOF) composites via integration of the individual advantages of MNP and MOF have been becoming a versatile photocatalyst. Moreover, owing to the synergist effect between each component, MNP/MOF composite photocatalysts usually show greatly promoted catalytic activity, selectivity and long-term recyclability. In this review, first of all, the widely adopted synthesis strategies of MNP/MOF composite are introduced comprehensively, and then their recent advances in photocatalysis including photocatalytic hydrogen production, carbon dioxide reduction, organic transformation reactions and photodegradation of pollutants are summarized and highlighted. Finally, challenges and perspectives among MNP/MOF based photocatalysis are also proposed and discussed for advancing further development in this hot research field.

Atomically precise gold (Au) nanoclusters (NCs) as visible light photosensitizers supported on the substrate for photoredox catalysis have attracted considerable attentions. However, efficient control of their photocatalytic activity and long-term stability is still challenging. Herein, we report a coordination-assisted self-assembly strategy in combination with electrostatic interaction to sandwich Au₂₅(Capt)₁₈ (abbreviated as Au₂₅, Capt = captopril) NCs between an inner core and an outer shell made of UiO-66, denoted as UiO-66@Au₂₅@UiO-66. Notably, the sandwich-like nanocomposite displays significantly enhanced catalytic activity along with an excellent stability when used in the selective photocatalytic aerobic oxidation of sulfide to sulfoxide. As comparison, Au₂₅ NCs simply located at the outer surface or insider matrix of UiO-66 (short as Au₂₅/UiO-66 and Au₂₅@UiO-66) show poor stability and low conversion, respectively. This structure regulated difference in the catalytic performances of three nanocomposites is assigned to the varied distribution of active sites (Au NCs) in metal-organic frameworks (MOFs). This work offers the opportunity for application of nanoclusters in catalysis, energy conversion and even biology.

Ultrathin metal-organic framework (MOF) nanosheets are attracting great interest in catalysis due to their unique and intriguing two-dimensional (2D) features. Although many progresses have been achieved, it is still highly desirable to develop novel strategies for controllable synthesis of the well-defined ultrathin MOF nanosheets. Herein we report a polyvinylpyrrolidone (PVP)-assisted route to synthesize the ultrathin Ni-MOF nanosheets characteristic of 1.5 nm in thickness, in which PVP is reacted with 2-aminoterephthalic acid (H₂BDC-NH₂) via formation of C=N bond, followed by coordination with Ni²⁺ ions to form the ultrathin MOF nanosheets. Impressively, when used in the Knoevenagel condensation reactions of propane dinitrile with different aldehydes, ultrathin Ni-MOF nanosheets display the significantly enhanced catalytic activity and good stability in respect with the bulk Ni-MOF, mainly owing to the exposed active sites as well as facile mass transfer and diffusion of substrates and products.

Multifunctional core–shell nanostructures formed by integration of distinct components have received wide attention as promising biological platforms in recent years. In this work, crystalline zeolitic imidazolate framework-8 (ZIF-8), a typical metal-organic framework (MOF), is coated onto single gold nanorod(AuNR) core for successful realization of synergistic photothermal and chemotherapy triggered by near-infrared (NIR) light. Impressively, high doxorubicin hydrochloride (DOX) loading capacity followed by pH and NIR light dual stimuli-responsive DOX release can be easily implemented through formation and breakage of coordination bonds in the system. Moreover, under NIR laser irradiation at 808 nm, these novel AuNR@MOF core–shell nanostructures exhibit effective synergistic chemo-photothermal therapy both in vitro and in vivo, confirmed by cell treatment and tumor ablation via intravenous injection.

The inter-nanocrystal (NC) distance, necking degree, ordering level, and NC surface ligands all affect the electronic and optoelectronic properties of NC solids. Herein, we introduce a unique PbS structure of necking percolative superlattices to exclude the morphological factors and study the effect of ligands on the NC properties. X-ray photoelectron spectroscopy data indicate that 1, 2-ethanedithiol (EDT), oxalic acid, mercaptopropionic acid, and NH₄SCN (SCN) ligands were attached to the surface of NCs by substrate-supported ligand exchange. Field-effect transistors were tested and photodetector measurements were performed to compare these NC solids. An SCN-treated film had the highest mobility and responsivity under high-power intensity irradiation owing to its high carrier density, whereas an EDT-treated film had the lowest mobility, photocurrent, and dark current. These findings introduce new avenues for choosing suitable ligands for NC applications.