Anchoring heterometallic cluster on P-doped carbon nitride for efficient photocatalytic nitrogen fixation in water and air ambient

Light-driven nitrogen fixation to produce ammonia is a green and economical technology of nitrogen reduction but is still quite challenging, especially in an air atmosphere without any sacrificial reagents.Herein, we demonstrate efficient photocatalytic nitrogen fixation using water and air directly by loading lanthanide–transition metal(4f–3d) cluster NdCo_(3) on two-dimensional P-doped graphitic carbon nitrides(PCN) material surface. Benefiting from the increase in the number of nitrogen vacancies(NVs) and highly matched band gap structure and excellent hole trapping ability of clusters, the NdCo_(3)/PCN photocatalyst exhibits efficient nitrogen reduction activity with 371(in air) and 825 μmol h^(-1)g^(-1)(in pure nitrogen)without any sacrificial reagents. The introduction of potassium sulfate inhibits hydrogen production and promotes nitrogen reduction activation. This work suggests that anchoring precisely structured clusters on 2D materials may enhance photocatalytic nitrogen reduction under normal temperature and pressure.

Molecular solid solution of lanthanide-titanium-oxo clusters with enhanced photocatalytic hydrogen evolution

Molecular solid solutions of metal clusters containing different metal centers with well-defined structures can accurately regulate the HOMO-LUMO gap,but are rarely available.Herein,a series of colorless lanthanide-titanium-oxo clusters Ln_(2)Ti_4(μ_(2)-O)_(2)(μ_(3)-O)_4(Piv)_(10)(THF)_(2)(Ln_(2)Ti_4,Ln = Eu,Gd,Tb,and Ce,HPiv = pivalic acid) were synthesized by the reaction of pivalic acid with Ln(Ac)_(3) and titanium isopropoxide.The light yellow crystal of cluster solid solutions Eu_(2)Ti_(4-x)Cd_(x),containing a mixture of Eu_(2)Ti_4 and Eu_(2)Ti_(3)Cd,was obtained by in situ doping Cd^(2+) and S^(2–).Eu_(2)Ti_(3.92)Cd_(0.08) displays efficient photocatalytic hydrogen evolution activity without a co-catalyst,which is up to 2.6 times that of Eu_(2)Ti_4.Femtosecond time-resolved transient absorption spectroscopy and spin-polarized density functional calculations showed that the enhanced photocatalytic performance of Eu_(2)Ti_(4-x)Cd_(x) can be attributed to the narrower HOMO-LUMO gap and lower LUMO position than that of Eu_(2)Ti_4.This studyprovides an in situ doping method to realize the simple preparation of cluster solid solution.

Lanthanide-oxo clusters for efficient catalytic reduction of carboxamides

The reduction of carboxamides into high value-added amines is a very interesting but great challenging topic.Herein we demonstrate that polynuclear lanthanide-oxo clusters Ln16(Ln=Eu and Gd)can be used as efficient catalyst to reduce primary and secondary carboxamides to amines with excellent yield of 71%-98%and broad substrates scope.The methodology can extend to the gram-scale synthesis of phenethylamine drug with 93%yield.Based on the isolation and characterization of catalytic intermediates,a catalytic mechanism involving multipath reaction is proposed.This work provides efficient lanthanide cluster catalysts for the reduction of carboxamides to amines.

Synthesis,Structure and Magnetic Behavior of a Novel Series of Trinuclear Windwheel Complexes

A new family of trinuclear windwheel complexes with molecular formula [M^(II)_(3)(tpa)_(3)(μ-ttc)](ClO_(4))_(3)·n(sol) (ttc = 1,3,5-triazine-2,4,6-trithiol;tpa = tris(2-pyridylmethyl)amine;M = Mn,n = 2,sol = CH_(3)CN,1;M = Co,n = 1,sol = CH_(3)CN,2;M = Ni,n = 0,3) were synthesized and characterized.Single-crystal X-ray diffraction revealed that three metal centers in 1—3 are connected by ttc bridge,forming a regular triangular MII3 core.Each metal center is bonded by chelating S,N atoms from ttc and by N atoms from tpa.Magnetic studies showed that 1—3 displayed antiferromagnetic behavior and further gave the easy-axis anisotropy (D = −0.77 cm^(−1) for 1 and −8.13 cm^(−1) for 2) and easy-plane anisotropy (D = 5.08 cm^(−1) for 3).Moreover,2 exhibited field-induced slow magnetic relaxation behavior and their effective energy barriers were roughly evaluated Ueff = 6.9 K.

Synthesis,structures and photoluminescence of uranyl polyoxometalate clusters based on trilacunary[TeW_(9)O_(33)]^(8-)

Synthesis of uranyl polyoxometalate clusters attract more attention but remain great challenging.Herein,two uranyl polyoxometalate inorganic clusters of{Na_(6)(NH_(4))_(19)[(TeW_(9)O_(33))_(4)[TeO_(2)(OH)](UO_(2))4(H_(2)O)_(2)]·50H_(2)O}n(1,Te-U_(4))and(NH_(4))18{Na@[(TeW_(9)O_(32)OH)(TeW_(9)O_(33))_(2)[TeO(OH)][W_(3)O_(12)(μ_(3)-OH)](UO_(2))_(6)(μ_(2)-OH)_(2)H_(2)O]}·75H_(2)O(2,Te-U6)were prepared using trilacunary[α-B-TeW_(9)O_(33)]8-as inorganic ligands.Structural analysis showed that compound 1 is a one-dimensional chain structure formed by tetrameric aggregates of[(α-B-TeW_(9)O_(33))_(4)(TeO_(2)(OH))(UO_(2))_(4)(H_(2)O)2]25-as nodes and Na+ions as linkers.The anionic tetrameric aggregates in 1 is made of two sandwich-type dimers of[(TeW_(9)O_(33))_(2)(UO_(2))_(2)H_(2)O]12-bridged by a[TeO_(2)(OH)]-unit.Compound 2 is a triangular trimeric architecture templated by Na+ion.The solid-state luminescence emission spectra of compounds 1 and 2 show the characteristic peaks of uranyl ions.Compound 1 with one-dimensional chain structure exhibited a higher photoluminescence quantum yields(PLQY)than that of 2,due to the more rigidity of 1 reducing the nonradiative transitions.

Encapsulating a Ni（Ⅱ） molecular catalyst in photoactive metal–organic framework for highly efficient photoreduction of CO2

Photocatalytic reduction of CO2 to CO is a promising strategy for reducing atmospheric CO2 levels and storing solar radiation as chemical energy.Here,we demonstrate that a molecular catalyst[NiⅡ(bpet)(H2O)2]successfully encapsulated into a highly robust and visible-light responsive metal–organic framework(Ru-UiO-67)to fabricate composite catalysts for photocatalytic CO2 reduction.The composite Ni@Ru-UiO-67 photocatalysts show efficient visible-light-driven CO2 reduction to CO with a TON of 581 and a selectivity of 99% after 20-h illumination,because of the facile electron transfer from Ru-photosensitizer to Ni(Ⅱ)active sites in Ni@Ru-UiO-67 system.The mechanistic insights into photoreduction of CO2 have been studied based on thermodynamical,electrochemical,and spectroscopic investigation,together with density functional theory(DFT)calculations.This work shows that encapsulating molecular catalyst into photoactive MOF highlights opportunities for designing efficient,stable and recyclable photocatalysts.

2020 roadmap on pore materials for energy and environmental applications

Porous materials have attracted great attention in energy and environment applications,such as metal organic frameworks(MOFs),metal aerogels,carbon aerogels,porous metal oxides.These materials could be also hybridized with other materials into functional composites with superior properties.The high specific area of porous materials offer them the advantage as hosts to conduct catalytic and electrochemical reactions.On one hand,catalytic reactions include photocatalytic,p ho toe lectrocatalytic and electrocatalytic reactions over some gases.On the other hand,they can be used as electrodes in various batteries,such as alkaline metal ion batteries and electrochemical capacitors.So far,both catalysis and batteries are extremely attractive topics.There are also many obstacles to overcome in the exploration of these porous materials.The research related to porous materials for energy and environment applications is at extremely active stage,and this has motivated us to contribute with a roadmap on ’porous materials for energy and environment applications’.

Enhanced proton conductivity of Mo_(154)-based porous inorganic framework

The construction of inorganic porous frameworks from discrete polyoxometalate(POM)units is a major research challenge.Herein,a three-dimensional(3D)all-inorganic porous structure{Mo_(154)}_n that consists of classic Mo_(154)rings connected by Mo–O–Mo covalent bonds was synthesized.Interestingly,the proton conductivity of the 3D-{Mo_(154)}_n framework is 1.1×10^(-2)S cm^(-1)at 22℃and 100%relative humidity(RH),which is one of the highest proton conductivities reported thus far for POM-based conductive materials.Compared to the discrete{Mo_(154)}cluster and 1D-{Mo_(154)}_n,the enhanced conductivity of 3D-{Mo_(154)}_n suggests that assembling POM-based all-inorganic porous frameworks is a promising method for designing proton-conductive materials.