NH₂-UiO-66 Metal–Organic Framework Nanoparticles for Hydroxide Ion Conductive Photoswitches

Abstract

Stimuli-responsive conductive MOF nanoporous materials have been considered to have great potential for photoelectric conversion, information processing, bioelectronics, and smart devices. However, lightregulating hydroxide ion conduction of MOFs is rarely reported. Herein, a reversible optical switch on hydroxide ion conduction has been achieved based on the intrinsic localized photothermal heating of NH 2 -UiO-66 nanoparticles. The amino group on the organic ligand of NH 2 -UiO-66 can build a hydrogen-bond network with water molecules to promote hydroxide ion transport in the nanochannel and cause an absorption band in the visible light region. Irradiated by visible light, NH 2 -UiO-66 nanoparticles can absorb light and convert it into heat, resulting in partial removal of water molecules in the nanopores and destroying the hydroxide ion transport path. Then, the hydroxide ion conductivity decreased by 2 orders of magnitude. When turning off the light, the hydroxide ion conductivity can restore quickly. This work will promote the development of remotely controlled hydroxide ion conductive smart devices.

Coupling effects between metal–organic framework derivatives and oxygen-deficient TiO2 nanotubes: identified charge-transfer processes and photoelectric synergistic effect

“…The EIS Nyquist plots showed that the charge-transfer resistance of the Ar-ZrO 2 /Ti 2 O 3 -TNTs decreased after self-assembly, which was highly dependent on the Ar-ZrO 2 loading in the Ti 2 O 3 -TNTs. 41 The minimal impedance arc of Ar-ZrO 2 /Ti 2 O 3 -TNTs confirmed the better conductivity and interfacial chargetransport properties, which were consistent with the I-t curve results. A crucial aspect of the effectiveness of photoelectric catalysis is the photogenerated carrier-separation properties.…”

“…Apparently, the semicircular structure of Ar-ZrO 2 /Ti 2 O 3 -TNTs was suppressed, indicating that the strong interfacial interaction between Ar-ZrO 2 and Ti 2 O 3 -TNTs immensely enhanced the conductivity of the photoelectrode. The EIS Nyquist plots showed that the charge-transfer resistance of the Ar-ZrO 2 /Ti 2 O 3 -TNTs decreased after self-assembly, which was highly dependent on the Ar-ZrO 2 loading in the Ti 2 O 3 -TNTs 41. The minimal impedance arc of Ar-ZrO 2 /Ti 2 O 3 -TNTs confirmed the better conductivity and interfacial chargetransport properties, which were consistent with the I-t curve results.…”

Unravelling the Multiple Synergies in MOF/CMP Supramolecular Heterojunction for Enhanced Artificial Photosynthesis

“…[ 24 ] The peak at 772 cm −1 for both NU and 40NU@FNBZ corresponds to the wagging vibration of the NH bond in primary aromatic amine. [ 25 ] The solid‐state 13 C‐CP/MAS NMR ( 13 C cross polarization magic angle spinning nuclear magnetic resonance) spectra confirm the structure of NU (Figure S1, Supporting Information) and FNBZ (Figure S2, Supporting Information), while 40NU@FNBZ displays the combined carbon characteristic peaks of both (Figure 1b). Moreover, a new peak at 145.5 ppm (Figure 1b inset) on 40NU@FNBZ corresponds to C1 on benzothiadiazole after the replacement of fluorine by the amino group (Figure S3, Supporting Information).…”

Hydroxide ion-conducting metal–organic frameworks for anion-exchange membrane applications

“…Although these values are generally low, e.g. 2.3 × 10 −9 S cm −1 in the case of the fairly hydrophobic ZIF-8, 38 other representatives have higher conductivities, including NH 2 -UiO-66(Zr) with a remarkable performance of 2 × 10 −3 S cm −1 in dark conditions, 107 when the formation of a hydrogen-bonded network of water molecules facilitated by the amino groups is unhindered. An interesting and somewhat contradictory effect was observed for the [Ni 8 (OH) 4 (H 2 O) 2 (BDP_X) 6 ] (H 2 BDP_X = 1,4-bis(pyrazol-4-yl)benzene-4-X, X = H, OH, NH 2 ) metal–organic frameworks.…”