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Three photosensitive tert- butylcalix[n]arene (TBC[n], n = 4, 6, 8)-protected titanium-oxo clusters (TOCs), formulated as [Ti 4 (μ 3 -O) 2 (TBC[4]) 2 (O i Pr) 4 (DEF) 2 ]·DEF ( 1 , TBC[4]-Ti 4 , DEF = N , N -diethylformamide), [Ti 4 (μ 4 -O)TBC[6](OCH 3 ) 9 ]·H 2 O ( 2 , TBC[6]-Ti 4 ), and [Ti 4 (μ 3 -O) 2 (O i Pr) 4 TBC[8](DEF) 2 ]·DEF ( 3 , TBC[8]-Ti 4 ), were successfully synthesized and characterized. Because of the generation of charge transfer from TBC[n] to the TiO core, the three TBC[n]-decorated TOCs show a broadened visible-light absorption and narrowed optical band gap based on the UV-visible spectra and density functional theory calculations. The corresponding photosensitive electrodes prepared using these three TOCs exhibit stable photocurrent responses. Furthermore, their photocatalytic performances for hydrogen evolution and methylene blue degradation were evaluated, and all of the materials display excellent photocatalytic activity and stability. The calixarene-Ti coordination is therefore an effective strategy to enlarge the visible-light absorption band of Ti-O materials and improve their photoelectric/photocatalytic performances.

Nonlinear-optical (NLO) crystals, which can regulate the laser wavelength through a cascading second-harmonic-generation technique, have been widely utilized in the field of optoelectronics. In this work, we grew the NLO borate crystal Rb 3 YB 6 O 12 (RYBO) using the spontaneous crystallization method. RYBO crystallizes in a chiral trigonal space group of R 32 with a new type of structural arrangement built from Y-O short chains and B 5 O 10 groups. It is significantly different from the known structure of chemical analogues Rb 3 REB 6 O 12 (RE = Nd, Eu) not only in the halved unit cell parameter but also in the Y-O connection manner. The NLO response of RYBO is about 0.8KDP, 8-fold larger than that of KB 5 O 8 ·4H 2 O with the same B 5 O 10 groups because of the coexistence of two NLO-active units of the distorted YO 6 octahedra and B 5 O 10 anions. Thanks to the short ultraviolet (UV) cutoff, RYBO may have potential NLO applications in the UV and even deep-UV spectral regions.

Ti-based layered double hydroxides (LDHs) have enormous potential in photocatalysis, electrocatalysis, and photoelectrocatalysis. However, Ti-based LDHs are rarely reported because of the difficulties of the preparation process, in which the Ti precursors are more prone to hydrolysis into titanium hydroxide. In this work, toward robust, efficient, and earth-abundant electrocatalysts for water oxidation in alkaline environments, we have engineered Ti-doped Ni(OH) 2 nanosheet arrays on carbon cloth [Ti-Ni(OH) 2 /CC] with a facile solvothermal and surfactant-free method. The experimental tests show that the activity of Ti-Ni(OH) 2 -1/CC (∼12.5 atom % Ti substitution) is optimal among these materials. In addition, the activity is correlated with the Ti substitution ratio and reversed with higher Ti doping level (≥25 atom % Ti substitution). Therein, η 10 of Ti-Ni(OH) 2 -1/CC is as low as 196 mV, and it is still maintained at 210 mV after a long-term chronopotentiometry (CP) test at a constant current density of 10 mA cm -2 for 32 h, demonstrating superior activity and long-term durability. Density functional theory calculations further reveal that dilute Ti substitution produces extra active sites and promotes more optimal OH* adsorption to the surface of the electrocatalyst.

Up to now, orchestrating the coexistence of Eu 2+ and Eu 3+ activators in a single host lattice has been an extremely difficult task, especially for the appearance of the characteristic emission of Eu 2+ and Eu 3+ in order to generate white light. Nevertheless, here we demonstrate a new Eu 2+ /Eu 3+ coactivated SrAl 3 BO 7 nanocrystalline phosphor with abundant and excellent multichannel luminescence properties. A series of Eu 2+ /Eu 3+ coactivated SrAl 3 BO 7 nanocrystalline phosphors were prepared through a Pechini-type sol-gel method followed by a reduction process. With excitation of UV/NUV light, the prepared SrAl 3 BO 7 :Eu 2+ ,Eu 3+ phosphors show not only the characteristic f-f transitions of Eu 3+ ion ( 5 D J → 7 F J,J' , J, J' = 0-3), but also the 5d → 4f transitions of Eu 2+ ion with comparable intensity from 400 to 700 nm in the whole visible spectral region. The luminescence color of the SrAl 3 BO 7 :Eu 2+ ,Eu 3+ phosphor can be tuned from blue, blue-green, white, and orange to orange-red by changing the excitation wavelength, the overall doping concentration of europium ions (Eu 2+ , Eu 3+ ), and the relative ratio of Eu 2+ to Eu 3+ ions to some extent. A single-phase white-light emission has been realized in SrAl 3 BO 7 :Eu 2+ ,Eu 3+ phosphor. The obtained SrAl 3 BO 7 :Eu 2+ ,Eu 3+ phosphor has potential application in the area of NUV white-light-emitting diodes.