Tripyridine‐Derivative‐Derived Semiconducting Iodo‐Argentate/Cuprate Hybrids with Excellent Visible‐Light‐Induced Photocatalytic Performance

Abstract

Through regulating the pH values, a series of iodo‐argentate/cuprate hybrids, [Me3(4‐TPT)]4[Ag6I18] (1, Me3(4‐TPT)=N,N′,N′′‐trimethyl‐2,4,6‐tris(4‐pyridyl)‐1,3,5‐triazine), [Me3(4‐TPT)][M5I8] (M=Ag/2, Cu/2 a), [Me3(3‐TPT)][M5I8] (Me3(3‐TPT)=N,N′,N′′‐trimethyl‐2,4,6‐tris(3‐pyridyl)‐1,3,5‐triazine, M=Ag/3, Cu/4), which exhibit adjustable structural variations with different dimensional structures, have been obtained under solvothermal conditions. They are directed by two types of in situ N‐alkylation TPT‐derivatives (Me3(4‐TPT) for 1/2/2 a and Me3(3‐TPT) for 3/4) and represent the isolated units (1), 1D polymeric chain (4), 2D layered structures (2/2 a, 3) based on diverse metal iodide clusters. These compounds possess reducing band gaps as compared with the bulk β‐AgI and CuI and belong to potential semiconductor materials. Iodocuprates feature highly efficient photocatalytic activity in the sunlight‐induced degradation of organic dyes. The detailed study on the possible photocatalytic mechanism, including radical trapping tests and theoretical calculations, reveals that the N‐alkylation TPT moieties contribute to the narrow semiconducting behavior and effectively inhibit the recombination of photogenerated electron‐hole pairs, which result in an excellent visible‐light‐induced photocatalytic performance.

A 3D Iodoplumbate Semiconducting Open Framework with Visible‐light‐induced Photocatalytic Performance

“…Recently, our research focusing on the systematic exploration of halometallates using the conjugated polypyridine derivatives as SDAs has made some progress . These previous study indicated that N ‐alkylation conjugated polypyridine cations as SDAs and electron acceptors can effectively decrease the band gap and accordingly increase the absorption of the visible light of the resultant materials.…”

“…Notably, the N ‐alkylation reaction of bpanth and CH 3 OH can also be further verified by the characteristic absorption peaks of −CH 3 group in IR spectra (Figure S3). The absorption bands around 2914 and 1390 cm −1 are directly related to the stretching vibrations and in‐plane bending vibration of C−H bond of −CH 3 unit, respectively, indicating that bpanth has been methylated and further directing the resultant materials …”

“…[42,43] Recently,o ur research focusingo nt he systematic exploration of halometallates using the conjugated polypyridine derivatives as SDAs has made some progress. [44][45][46][47] These previous study indicated that N-alkylation conjugated polypyridinec ations as SDAs ande lectron acceptors can effectively decrease the band gap and accordingly increaset he absorption of the visible light of the resultant materials. For example, the tripyridine-derivatives derived iodoargentates and iodocuprates, [Me 3 (4-TPT)][M 5 I 8 ], [Me 3 (3-TPT)][M 5 I 8 ]( M= Ag, Cu;4 -TPT = 2,4,6tris(4-pyridyl)-1,3,5-triazine,3 -TPT = 2,4,6-tris(3-pyridyl)-1,3,5-triazine), possess narrow band gaps of 1.05-2.19 eV ande xhibit excellent photodegradation activity.H ence, to further investigate the impact of different conjugated organic cations on the crystal structure and band structure on halometallates, we select the conjugated bpanth (bpanth = 9,10-bis(4-pyridyl)anthracene) as cation templates,t hrough the in situ N-alkylation synthesis, achieving a3 Di norganic-organic hybrid iodoplumbate, [Me 2 (bpanth)][Pb 4 I 10 ]( 1), which possessess mall band gap and exhibits efficient photocatalytic performance in visiblelight induced degradation.Compound 1 is synthesized by an in situ solvothermalr eaction.…”

“…The absorption bands around2 914 and 1390 cm À1 are directly relatedt ot he stretching vibrations andi n-plane bending vibration of CÀHb ond of ÀCH 3 unit, respectively,i ndicating that bpanth has been methylated and further directing the resultantmaterials. [46] Solid-state UV/Vis absorption spectrumw as calculated from the diffuse reflectance data by using the Kubelka-Munk function ( Figure 2). [50] An arrow band gap energy of 2.06 eV is observedb ye xtrapolation of the linear portion of the absorption edge, which suggests 1 being ah ybrid semiconducting material.…”

“…[16,43,[52][53][54][55][56][57] The AO and BQ have more obviousi nfluence on the photocatalytic activity,w hich indicating that h + and O 2 C À are the main active speciesint he photodegradation process (Figure 3c).Compound 1,a sw ell as the reportedh ybrid halometallates containing conjugatedo rganic cations, such as [N-ethyl-4-cyanopyridinium][Ag 2 I 3 ], [9] [N-benzylpyridinium] 2 [Cu 6 I 8 ], [58] [(Me) 2 -2,2'-bipy][Cu 8 I 10 ], [55] [Ni(2,2'-bipy)(THF) 2 (H 2 O) 2 ](Ag 10 I 12 )·2DMF (THF = tetrahydrofuran, DMF = N,N'-dimethylformamide, 2,2'bipy = 2,2'-bipyridine), [59] and [Pb 5 Cu 2 I 16 ][(Me) 2 (4-TPT)] 2 (4-TPT = 2,4,6-tris(4-pyridyl)-1,3,5-triazine), [45] possess narrow band gaps of 1.35-2.74 eV.R eportedly, on the basis of electronic band structuralc alculation, the conductionb ands of most conjugated organic cations directed halometallates are primarily occupied by the conjugatedo rganic moieties, while the valence bandsa re mainly made up by anionic inorganic networks. [46,55] The contribution of conjugated organic moieties to conduction bands decreasing the energy position and leading to the small band gaps. Therefore, it is speculated that the [Me 2 (bpanth)] 2 + moietiesg reatly contribute to the conduction band, decreasing the energy position and resulting in an arrow band gap, accordingly increasing visible-light absorption and making 1 a good visible-light driven photocatalyst.Additionally,t oc onfirm the thermostability of the solid samples, the TG study was performed ( Figure S5).…”