Anisotropic phenanthroline-based ruthenium polymers grafted on a titanium metal-organic framework for efficient photocatalytic hydrogen evolution

Abstract

Conjugated polymers and titanium-based metal-organic framework (Ti-MOF) photocatalysts have demonstrated promising features for visible-light-driven hydrogen production. We report herein a strategy of anisotropic phenanthroline-based ruthenium polymers (PPDARs) over Ti-MOF, a tunable platform for efficient visible-light-driven photocatalytic hydrogen evolution reaction (HER). Several analytical methods including X-ray absorption spectroscopy (XAS) revealed the judicious integration of the surface-active polymer over the Ti-MOF reinforcing the catalytic activity over the broad chemical space. PPDAR-4 polyacrylate achitecture led to a substantial increase in the H2 evolution rate of 2438 µmolg−1h−1 (AQY: 5.33%) compared to pristine Ti-MOF (238 µmol g−1 h−1). The separation of photogenerated charge carriers at the PPDAR-4/Ti-MOF interface was confirmed by the optical and electrochemical investigations. The experimental, as well as theoretical data, revealed their physical and chemical properties which are positively correlated with the H2 generation rate. This offers a new avenue in creating polymer-based MOF robust photocatalysts for sustainable energy.

Charge Transfer-Regulated Bimetallic ZnCd-ZIF-8/Graphene Oxide Hybrid Nanostructures for Solar Hydrogen Generation

“…The photophysical and optical properties of the synthesized photocatalysts have been measured through diffuse reflectance spectra confirming the presence of ZIF-8 over GO as shown in Figure a, along with the absorbance of ZnCd-ZIF-8 and GO. The doping of ZIF-8 over GO is mostly observed over the absorption bands of 285 and 375 nm, which leads to an increase in the intensity and shift in the absorption region which is mostly due to the electronic transitions through π–π interactions . The Kubelka–Munk plot of ZnCd-ZIF-8, GO is shown in Figure b and Figure S3a as 4.70 and 2.2 eV which has the absorption over the visible region.…”

“…The doping of ZIF-8 over GO is mostly observed over the absorption bands of 285 and 375 nm, which leads to an increase in the intensity and shift in the absorption region which is mostly due to the electronic transitions through π−π interactions. 39 The Kubelka−Munk plot of ZnCd-ZIF-8, GO is shown in Figure 3b and Figure S3a as 4.70 and 2.2 eV which has the absorption over the visible region. ZnCd-ZIF-8 with a bandgap of 4.70 eV shows only absorption spectra over the UV region; the shift in the absorption range toward the redshift has been observed over GO/ZnCd-ZIF-8(10) leading to absorption in the visible region with a bandgap of 3.7 eV (Figure S3b).…”

Modulated Ultrathin NiCo-LDH Nanosheet-Decorated Zr3+-Rich Defective NH2–UiO-66 Nanostructure for Efficient Photocatalytic Hydrogen Evolution

“…The asymmetrical stretching vibration of the reduced peak, ν as (C�O), at ∼1665 cm −1 , ν as (COO − ) at ∼1446 cm −1 , and ν as (C−O) at ∼1256 cm −1 (Figure 1b) is clearly evident for silver-catalyzed decarboxylation reaction to confirm the formation of defective NH 2 − UiO-66 maintaining the structural integrity. 22,23,48 In addition, the characteristic bands associated with both LDHs and MOFs are illustrated in the FTIR spectrum of NiCo-LDH@NH 2 − UiO-66 and NiCo-LDH@NH 2 −UiO-66-D composites (Figure S1). Moreover, atomic force microscopy (AFM) analyzes the thickness of NiCo-LDH nanosheets in order to confirm their ultrathin features.…”

“…Recent reports outlined the amination of the terephthalic acid linker in UiO-66 to tailor the band gap, allowing visible light photocatalysis by red shifting from UV radiation. , One of the prime obstacles for photocatalytic hydrogen evolution reaction (HER) applications are enhancing the reactivity of MOFs. In this context, introducing cocatalysts and forming heterojunctions are two common strategies for improving the photocatalytic response of NH 2 –UiO-66. , Exploitation of electrical interaction effects at the heterojunctions is an excellent strategy to adjust the engagement between catalysts and to modulate their optoelectronic properties for the improvement of photocatalytic performance. , Furthermore, few studies have focused on modifying the MOF base by introducing defect engineering for photocatalytic performance. − The defect insertion into the MOF base is often accompanied by electron localization, lattice distortion, and bond breaking and reformation, all of which may supplement the number of active sites and modify the local environment. − It is anticipated that a superior MOF base with more active sites and faster electronic pathways would contribute significantly in the enhancement of the HER performance; hence, developing MOF derivatives in regard to photocatalysis is farsighted. Furthermore, the strong redox potential which is negatively charged over Zr 4+ showed less photocatalytic activity in the NH 2 –UiO-66 framework, and the formation of Zr 3+ species in the NH 2 –UiO-66 framework indicates the electron transfer from the linkage moiety to the Zr–O cluster on the electronic structure of the MOF to improve the photocatalytic activity. , …”

Conducting 1D nanostructures from light-stimulated copper-metalated porphyrin–dibenzothiophene

“…30,31 Metal porphyrin and phenanthroline complexes have been well-reported for their intrinsic, intense and efficient light absorption capacity. [32][33][34] However, detailed investigation is indispensable to generate efficient porphyrin-based redoxactive systems for future commercialization. Recently, we have reported light-stimulated freebase and metalated thianthreneappended porphyrin derivatives, revealing that both derivatives exhibit a charge transfer phenomenon.…”