The exploration of efficient electrocatalysts is the central issue for boosting the overall efficiency of water splitting. Herein, pertinently creating active sites and improving conductivity for ...metal–organic frameworks (MOFs) is proposed to tailor electrocatalytic properties for overall water splitting. An Ni(II)‐MOF nanosheet array is presented as an ideal material model and a facile alkali‐etched strategy is developed to break its NiO bonds accompanied with the introduction of extra‐framework K cations, which contribute to creating highly active open metal sites and largely improving the electrical conductivity. As a result, the assembled defect‐Ni‐MOF||defect‐Ni‐MOF electrolyte cell delivers a lower and stable voltage of 1.50 V at 10 mA cm−2 in alkaline medium for overall water splitting, comparable to the combination of iridium and platinum as benchmark catalysts.
The introduction of defects into metal–organic framework (MOF) by alkali‐etching treatment to create rich active sites and tailor electrical conductivity is proposed. The resultant defect‐rich Ni(II)‐MOF nanosheet array exhibits excellent electrocatalytic overall water splitting performance, comparable to the noble metal‐based benchmark catalysts.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Despite numerous inherent merits of metal–organic frameworks (MOFs), structural fragility has imposed great restrictions on their wider involvement in many applications, such as in catalysis. Herein, ...a strategy for enhancing stability and enabling functionality in a labile Zr(IV)‐MOF has been proposed by in situ porphyrin substitution. A size‐ and geometry‐matched robust linear porphyrin ligand 4,4′‐(porphyrin‐5,15‐diyl)dibenzolate (DCPP2−) is selected to replace the 4,4′‐(1,3,6,8‐tetraoxobenzolmn3,8phenanthroline‐2,7(1H,3H,6H,8H)‐diyl)dibenzoate (NDIDB2−) ligand in the synthesis of BUT‐109(Zr), affording BUT‐110 with varied porphyrin contents. Compared to BUT‐109(Zr), the chemical stability of BUT‐110 series is greatly improved. Metalloporphyrin incorporation endows BUT‐110 MOFs with high catalytic activity in the photoreduction of CO2, in the absence of photosensitizers. By tuning the metal species and porphyrin contents in BUT‐110, the resulting BUT‐110‐50%‐Co is demonstrated to be a good photocatalyst for selective CO2‐to‐CO reduction, via balancing the chemical stability, photocatalytic efficiency, and synthetic cost. This work highlights the advantages of in situ ligand substitution for MOF modification, by which uniform distribution and high content of the incoming ligand are accessible in the resulting MOFs. More importantly, it provides a promising approach to convert unstable MOFs, which mainly constitute the vast MOF database but have always been neglected, into robust functional materials.
The in situ porphyrin substitution strategy is developed for modifying labile interpenetrated BUT‐109(Zr), affording BUT‐110 with enhanced chemical stability and photocatalytic activity. By tuning the species and contents of metalloporphyrin in BUT‐110, some of the BUT‐110 MOFs may serve as potential photocatalysts for selective CO2‐to‐CO reduction, in the absence of photosensitizer.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Exploring novel multifunctional rare earth materials is very important because these materials have fundamental interests, such as new structural facts and connecting modes, as well as potential ...technological applications, including optics, magnetic properties, sorption, and catalytic behaviors. Especially, employing these nanomaterials for sensing or catalytic reactions is still very challenging. Herein, a new superstable, anionic terbium‐metal–organic‐framework, H2N(CH3)2Tb(cppa)2(H2O)2, (China Three Gorges University (CTGU‐1), H2cppa = 5‐(4‐carboxyphenyl)picolinic acid), is successfully prepared, which can be used as a turn‐on, highly‐sensitive fluorescent sensor to detect Eu3+ and Dy3+, with a detection limitation of 5 × 10−8 and 1 × 10−4m in dimethylformamide, respectively. This result represents the first example of lanthanide‐metal–organic‐frameworks (Ln‐MOF) that can be employed as a discriminative fluorescent probe to recognize Eu3+ and Dy3+. In addition, through ion exchanging at room temperature, Ag(I) can be readily reduced in situ and embedded in the anionic framework, which leads to the formation of nanometal‐particle@Ln‐MOF composite with uniform size and distribution. The as‐prepared Ag@CTGU‐1 shows remarkable catalytic performance to reduce 4‐nitrophenol, with a reduction rate constant κ as large as 2.57 × 10−2 s−1; almost the highest value among all reported noble‐metal‐nanoparticle@MOF composites.
A new porous, anionic Tb‐metal–organic‐framework, China Three Gorges University (CTGU‐1), can serve as a turn‐on sensor for detection of Eu3+ and Dy3+, with different detection limits. Additionally, spontaneous in situ reduction and immobilization of ion‐exchanged Ag(I) to Ag nanoparticles in the anionic framework result in an Ag@CTGU‐1 composite, which can remarkably catalyze the reduction of 4‐nitrophenol.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Designing efficient multifunctional electrocatalysts for water and urea splitting to produce green hydrogen presents a significant yet worthwhile challenge. Herein, the morphology and electronic ...structure of cobalt metaphosphate (Co2P4O12) by vanadium (V) doping, resulting in improved electrocatalytic activity and stability for hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and urea oxidation reaction (UOR) are simultaneously regulated. Theory calculations show that V‐doped Co2P4O12 (V‐Co2P4O12) can boost the kinetics of catalytic reactions by optimizing the d‐band center of Co atoms and the binding strength of intermediates, as well as enhancing the density of states. Moreover, the doping of V into Co2P4O12 crystalline structure benefits the formation of a thicker amorphous layer during the catalytic process, which could enhance its alkaline corrosion resistance and stability. Additionally, the multilevel nanostructures of V‐Co2P4O12 provide rich active sites for catalytic reactions. As a result, a two‐electrode electrolyzer assembled by V‐doped Co2P4O12 delivers low voltages for overall water and urea splitting. The superior performance suggests that the proposed V‐doping strategy is a promising way to regulate electrocatalytic activity for catering to green electrocatalytic applications.
The morphology and electronic structure of the Co2P4O12 catalyst are simultaneously regulated by V doping, which endows the catalyst with enhanced hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and urea oxidation reaction (UOR) performance. Thanks to the excellent trifunctional catalytic performance, the assembled two‐electrode electrolyzers enable efficient overall water and urea splitting at low overpotentials.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
The selective adsorption/separation of C2 hydrocarbons has been realized in a “flexible-robust” MOF, Zn2(Atz)2Ox. Owing to the distinctive guest-dependent multistep adsorption behaviors and suitable ...guest–framework interactions, this MOF shows outstanding separation performance for C2H2/C2H4 mixtures in a wide range of temperature confirmed by a column breakthrough experiment.
Constructing stable palladium(II)-based metal–organic frameworks (MOFs) would unlock more opportunities for MOF chemistry, particularly toward applications in catalysis. However, their availability ...is limited by synthetic challenges due to the inertness of the Pd–ligand coordination bond, as well as the strong tendency of the Pd(II) source to be reduced under typical solvothermal conditions. Under the guidance of reticular chemistry, herein, we present the first example of an azolate Pd-MOF, BUT-33(Pd), obtained via a deuterated solvent-assisted metal metathesis. BUT-33(Pd) retains the underlying sodalite network and mesoporosity of the template BUT-33(Ni) and shows excellent chemical stability (resistance to an 8 M NaOH aqueous solution). With rich Pd(II) sites in the atomically precise distribution, it also demonstrates good performances as a heterogeneous Pd(II) catalyst in a wide application scope, including Suzuki/Heck coupling reactions and photocatalytic CO2 reduction to CH4. This work highlights a feasible approach to reticularly construct noble metal based MOFs via metal metathesis, in which various merits, including high chemical stability, large pores, and tunable functions, have been integrated for addressing challenging tasks.
Full text
Available for:
IJS, KILJ, NUK, PNG, UL, UM
The development of ethane (C2H6)‐selective adsorbents for ethylene (C2H4) purification, although challenging, is of prime industrial importance. Pillared‐layer metal‐organic frameworks (MOFs) possess ...facilely tunable pore structure and functionality, which means they have excellent potential for high‐performance C2H6/C2H4 separation applications. Herein, we report a family of isostructural pillared‐layer MOFs with various metal centers M and co‐ligands L, M2(D‐cam)4L2 (denoted M‐cam‐L; M = Cu, Co, Ni; L = pyz, apyz, dabco), with a variety of pore surface properties. All of the M‐cam‐L materials exhibit preferential adsorption for C2H6 over C2H4. In particular, Ni‐cam‐pyz exhibits the highest C2H6 capture capacity (68.75 cm3 g−1 at 1 bar and 298 K), Cu‐cam‐dabco possesses the greatest C2H6/C2H4 adsorption selectivity (2.3), and the lowest isosteric heat of adsorption is demonstrated for Cu‐cam‐pyz (20.1 kJ mol−1). Dynamic column breakthrough experiments also confirmed the excellent separation performance of M‐cam‐pyz and M‐cam‐dabco materials. The synthesis route of the M‐cam‐L materials is easily scaled‐up under laboratory conditions, and hence this class of MOFs is promising for practical C2H4 purification.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Two new three-dimensional (3D) multinodal Cd(II)–organic frameworks, Cd3(dccpa)(bipy)0.5(H2O)4·5H2O (1) and (CH3)2NH22Cd11(dccpa)4(DMF)4(H2O)8·4H2O (2) (H6dccpa = 3,4-di(3,5-dicarboxyl ...phenyl) phthalic acid, bipy = 4,4′-bipyridine), have been prepared and fully characterized. Compound 1 possesses a 3D neutral framework with a new (6,6,7)-connected topology based on a single trinuclear cluster, while 2 features a 3D anionic framework with a new (5,6,6,10)-connected topology containing mixed trinuclear and pentanuclear clusters. Remarkably, 1 and 2 show promising photocatalytic activities toward the degradation of rhodamine B and methyl blue, which suggests that different kinds of cluster units may exert different impacts on the decomposition of organic dyes.
Full text
Available for:
IJS, KILJ, NUK, PNG, UL, UM
Enhancing electrocatalytic water splitting performance by modulating the intrinsic electronic structure is of great importance. Here, porous bimetallic oxide and chalcogenide nanosheets grown on ...carbon paper denoted as NiCo
2
X
4
/CP (X = O, S, and Se) are prepared to demonstrate how the anion components affect the electronic structures and thereby disclose the correlation between their intermediates interaction and catalytic activities. The experimental characterization and theoretical calculation demonstrate that Se and S substitution can promote the ratio of Co
3+
/Co
2+
and thereby modulate the electronic structure accompanied with the upshift of d band centers, which not only enhance the inner conductivity but also regulate the interaction between the catalyst surface and intermediates, especially for the adsorption of absorbed H and hydroperoxy intermediates towards respective hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). As a result, a full alkaline electrolyzer using NiCo
2
Se
4
/CP and NiCo
2
S
4
/CP as cathode and anode delivers a low voltage of 1.51 V at 10 mA·cm
−2
, which is comparable even superior to most transition metal-based electrolyzers.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
