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IT-MOFs and their derived nanomaterials: a strategic approach towards stupendous photocatalysis. This mini-review elucidates the crystal fabrication strategy, and emerging photocatalytic applications of IT-MOFs.

Design and facile fabrication of a magnetically separable hetero-structure photocatalyst as well as an adsorbent having dual green benefits towards energy conversion and pollutant remediation are quite indispensable in the current scenario. In this regard, a composite of citrate capped Fe3O4 and UiO-66-NH2 has been designed to remediate Cr (VI) by adsorption and harvest photons from visible light for clean energy (H2) conversion. The material was prepared by the union of citrate capped Fe3O4 (CCM) and versatile aqueous stable Zr-based MOF (UiO-66-NH2) through in-situ solvothermal method. The composite of CCM with MOF (MU-2) was studied through sophisticated analysis techniques; PXRD, FT-IR, BET, UV–Visible DRS, PL, TG, HRTEM and XPS etc. to reveal the inherent characteristics of the material. BET surface analysis revealed high specific surface area (572.13 m2 g−1) of MU-2 in comparison to its pristine MOF. Furthermore, the dual function composite MU-2′s VSM studies showed that its magnetic saturation is 3.07 emu g−1 that is suitable for magnetic separation after desired reaction from aqueous media. The Cr (VI) sorption studies revealed that the composite adsorbent (MU-2) showed maximum monolayer adsorption capacity (Qm) of 743 mg g−1 which followed pseudo second order kinetics. Moreover, the sorption thermodynamics revealed that the process was spontaneous and endothermic in nature. In addition to it, the synthesized composite material displayed enhanced activity towards photocatalytic H2 evolution with a maximum evolution rate of 417 µmole h−1 with an apparent conversion efficiency (ACE) of 3.12 %. Typically, MU-2 displays high adsorptions of Cr (VI) as well as some extent of Cr (VI) reduction owning to its populous active sites and free carboxylate groups respectively. Moreover, the synergistic effect of CCM and UNH in the composite resulted in Z scheme mediated charge transfer mechanism that showed enhanced H2 photo-evolution rates. Hence, MU-2 can be readily utilized as magnetically retrievable dual function composite for Cr (VI) adsorption and photocatalytic H2 evolution.

In the existing eco-crisis, designing and engineering an efficient as well as water stable photocatalyst for energy conversion and pollutant abatement remains crucial. In this regard, a mixed linker type zirconium metal organic framework (Zr-MOF) with terepthalic acid based ditopic linkers were utilized to design a single component photocatalyst through single step solvothermal method to utilize photons from visible light illumination towards hydrogen energy (H

Metal organic framework (MOF) based semiconductor composites enhance the synergistic physio-chemical properties of pristine semiconducting materials. In general, MOFs are perceived as an attractive candidate for constructing new composite materials because of their facile synthesis, tuneable porosity, high surface area, populous active sites and surface functional groups. As such, many researchers have infused pure MOFs with other classes of materials such as supplementary MOFs, carbonaceous materials, oxides, metal NPs, quantum dots, polymers etc. to fabricate distinctive constructs with synergetic properties. Considering the accelerating development occurring in the field of 3D reticulated hybrid materials towards photocatalysis, it is quite essential to summarize and explore their vast possibilities. In this regard, we aim at performing an analysis of metal oxide integrated MOFs (MO@MOF) towards photocatalytic applications. Many researchers have been tempted to improve the functionalities of pristine MOFs by composite formation with metal oxides (such as UiO-66@WO3, Bi2O3@HKUST-1, ZnO@ZIF-8, Fe3O4@MIL-100 (Fe) etc.) and have reported its applications towards diverse areas of photo-catalysis. In this context, we have presented a holistic summarization focusing on the rational design, fabrication strategy, characterization aspects and underlying mechanistic charge dynamics of photocatalytic applications with metal oxide integrated metal organic frameworks.

In current scenario photocatalytic water splitting towards H2 evolution by heterogeneous photocatalysis is an emerging science for accepting the future global energy crisis in modern life. In this regard we have synthesized and modified Zr-based MOF i.e. UiO-66, UiO-66-NH2 and Au/UiO-66-NH2 by hydrothermal method and tested its efficiency towards H2 evolution. The synthesized photocatalyst were well characterized by XRD, FTIR, UV–Vis and Electrochemical analysis to determine their structural and electro chemical properties. The analysis result confirms the successful synthesis of these photocatalyst and reveals the enhanced photo catalytic efficiency of Au/UiO-66-NH2. The rate of H2 evolution was observed in the order Au/UiO-66-NH2 > UiO-66-NH2 > UiO-66. This can be attributed to the strong LSPR effect of noble metal Au and the enhanced visible light absorption capacity of linker due to the presence of –NH2 group. The Au nanoparticles acts as an electron collector from the conduction band of photo excited UiO-66-NH2 and hence inhibits the first recombination of electron-hole pairs. The photogenerated electrons accumulated on Au surface readily facilitate H2 production by reduction of H2O molecule. The maximum H2 evolution observed for Au/UiO-66-NH2 was 387 µmol/h. The observed photocatalytic performance of H2 evolution will provide an advantageous blue print for the fabrication of noble metals on MOF surface towards the future photocatalytic applications.

Harnessing the energy of photons by photocatalytic semiconducting materials is a topic of paramount interest in the present era because of its sustainable eco-friendly impact. The harnessed energy by photocatalyst is intricately employed for a plethora of photocatalytic applications, such as pollutant remediation, energy conversion, organic transformations and many more. Hence, the global research community has focused their interest on the design and development of cost-effective and actively efficient photocatalytic semiconductors crafted to the needs of a desired photocatalytic process. In this regard, the stimulation of a broad range of characterization techniques becomes an imperative necessity to reveal various physico-chemical properties of the semiconductor photocatalyst. This review aims to summarize the sophisticated characterisation techniques that are used to analyse various organic, inorganic and hybrid type photocatalysts by qualitative and quantitative methods. In detail, this review is centred on the techniques utilised to contemplate, as well as correlate the physical structure, topography, chemical state, elemental composition, electrochemical properties and band structures of a wide range of photocatalysts. The discussion of each characterization method consists of a concise fundamental explanation, followed by proper exemplification intended to disseminate to materials chemists, predominantly individuals who are near the beginning of their careers focused on the development of competent photocatalysts.

Hydrogen evolution from water splitting by means of a photocatalytic approach is an ideal future energy source and free of fossil reserves, in contrary photocatalytic O2 evolution remains a bottleneck due to high over potential and low efficiency. For reasonable use of solar light, photocatalysts must be sufficiently stable and efficient toward harvesting of sunlight from both theoretical and practical viewpoints. In this regard, here we have prepared MoS2-modified UiO-66-NH2 MOF through a facile hydrothermal technique and evaluated its efficiency toward photocatalytic H2 and O2 evolution by water splitting in the presence of sacrificial agents. A couple of similar type of analyses have been studied previously; however, this analysis represents a diverse scientific approach on the basis of interfacial contact toward reveal the actual potential of nanoflakes MoS2 as well as UiO-66-NH2. In this regard the as-synthesized photocatalyst was well-characterized by XRD, FTIR, UV-vis diffuse reflectance spectra, FESEM, HRTEM, XPS, and BET analysis techniques, which provide sufficient evidence toward successful synthesis of the pristine materials and efficacious anchorage of MoS2 on the active surface of UiO-66-NH2 by the ionic interaction between Zr-O and S/Mo. Among the synthesized photocatalysts (3 wt %) MoS2/UiO-66-NH2 shows the optimum outcome toward H2 and O2 evolution, i.e., 512.9 μmol/h (4.37 times greater than bare UiO-66-NH2) and 263.6 μmol/h (4.25 and 11.32 times greater than bare UiO-66-NH2 and MoS2, respectively). The superior performance obtained by the composite is due to the synergistic effect of pristine UiO-66-NH2 and MoS2 which proceeds through a type-II interband alignment for the facile channelization of excitons. This investigation will bestow a beneficial blue-print to construct challenging photocatalysts and to find out the paramount performance toward photocatalytic water redox reaction.

Environmental pollution and energy scarcity is a major issue of the current scenario which forbear the progress of developing world. To overcome these problems towards a sustainable future, the utilization of sunlight by means of photocatalysis can be regarded as a best and suitable pathway. To validate this purpose, design and development of efficient heterogeneous photocatalyst for harvesting solar energy should be the major research concern for scientific community. In this regard herein, we have prepared a series of stable and efficient CoTiO3/UiO-66-NH2 p-n junction mediated heterogeneous photocatalyst by hydrothermal method. The functionalised linker of UiO-66-NH2 provided an intimate interfacial contact with CoTiO3 by Co/Ti O N ionic interaction, as proved by HRTEM and XPS analysis. Moreover the inverted V-shaped Mott-Schottky plot confirmed the junction formation in the optimised CoTiO3/UiO-66-NH2 material. In addition, EIS and PL analysis also provides sufficient evidence about the hindrance of active species recombination in composite as a result of p-n hetero junction. LC-MS characterization technique traces the assorted intermediate species produced in the course of photodegradation of Norfloxacin and confirms its complete degradation to corresponding CO2, H2O and NH4+ by the optimised CoTiO3/UiO-66-NH2. The highest photo-catalytic activity obtained towards Norfloxacin degradation is 90.13% and H2 production is 530.87 µmol in 1 h. The enhanced photo-catalytic reaction follows Type-II p-n hetero junction charge transfer mechanism and thus, paves a new way to design MOF based heterojunction photocatalyst for diverse photo catalytic performance.

The present research reports the synthesis of two-dimensional (2D) sheet/flake-like nanostructures of crystalline carbon modified TiO2 (CT), B-TiO2 (B-CT), and S-TiO2 (S-CT) using a facile one-pot synthesis method. The crystallinity and phase purity (anatase) of the prepared nano-photocatalyst were characterised using X-ray diffraction, selected area electron diffraction (SAED) and high-resolution transmission electron microscopy (HRTEM) analysis. Furthermore, the morphological details and elemental content of the sample were studied via scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS), respectively. Additionally, the optoelectronic features of all of the prepared specimens were measured via UV-vis diffuse reflectance spectroscopy (DRS), photoluminescence (PL), impedance and Mott–Schottky studies. After successful characterisation, their photocatalytic performance was tested towards dinitrogen photo-fixation and tetracycline hydrochloride (TCH) degradation under visible light illumination. Moreover, the effective charge separation and greater availability of the active surface area led to the robust photocatalytic activity of the fabricated B-CT compared to the CT and S-CT samples, which correlates well with the PL, impedance and surface area analysis. B-CT displays the highest photocatalytic activity, i.e. 32.38 μmol L−1 (conversion efficiency = 0.076%) of ammonia production, and 95% tetracycline hydrochloride (10 ppm) degradation. Here, we have effectively designed a novel and productive pathway towards the enhancement of the photocatalytic performance of visible photon active TiO2-based materials for energy and environmental sustainability.

A mixed-valency bimetallic Ce/Zr MOF with Ce

UiO-66-NH2 (UNH), a Zr-based metal organic framework was synthesised by solvothermal technique. The formation of UNH was confirmed by XRD and SEM–EDX results. The adsorptive behaviour of UNH towards Cr(VI) was investigated with respect to pH, temperature, contact time and adsorbent dose. Radioanalytical techniques such as PIXE and INAA were employed for determination of adsorbed Cr(VI), which was well validated from Diphenylcarbazide method. Adsorption process was endothermic and followed pseudo second order kinetics. The maximum adsorption capacity was found to be 25.9 mg g−1 at pH 2.0 and adsorbent dose of 1 g L−1 in 3 h.

The abolition of environmental pollutants and production of hydrogen (H2) from water using a heterogeneous photocatalyst is a demanding science of the current scenario to solve the increasing environmental pollution and worldwide energy catastrophe in modern life. To validate this purpose, the design of low-cost and durable semiconductor-based photocatalysts with great light absorption capacity becomes the most challenging issue for researchers. Regarding this, herein the phosphotungstic acid (HPW)-anchored Zr6O4(OH)4(BDC)6 (UiO-66) metal-organic framework (MOF), i.e., HPW@UiO-66, has been prepared by a hydrothermal method and is efficient, stable, and capable of harvesting solar energy toward the degradation of tetracycline hydrochloride (TCH) and H2 production in the presence of a sacrificial donor. The ionic interaction between HPW and UiO-66 plays a key role toward the photostability and charge-transfer mechanism of the composite and is well characterized with X-ray diffraction, UV diffuse-reflectance spectroscopy, Fourier transform infrared, and X-ray photoelectron spectroscopy. A total of 30 wt % HPW@UiO-66 shows a maximum degradation of about 87.24% of a 20 ppm TCH solution in 60 min of solar-light irradiation and about 353.89 μmol/h of H2 production. The conduction- and valence-band potentials are well characterized with Mott-Schottky measurement and a delay charge recombination process through electrochemical impedance spectroscopy. The proposed mediator-free Z-scheme-oriented electron-hole migration route is well supported by photoluminescence, and the scavenger test well explains the better charge-carrier separation and high catalytic performance of the prepared composite. This research will bestow an advantageous blueprint to fabricate novel and challenging photocatalysts toward the photocatalytic treatment of environmental pollutants and H2 evolution.

Visible light harvesting by heterogeneous photocatalysts and their applications in organic transformation reactions for the synthesis of target molecules are quite demanding science in the current scenario. In this regard, herein, a novel metal (Au/Pd)-functionalized metal organic framework (UiO-66-NH2) was synthesized to carry out the Suzuki–Miyaura coupling (SMC) reaction under visible light irradiation at ambient conditions. In order to justify the claim regarding the formation of alloys, crystallinity, morphology, particle size, proper separation of excitons, elemental content and their environment, various sensitive characterization techniques such as XRD, XPS, HRTEM, BET surface area and UV-vis analysis were employed. A mechanistic approach by means of experimental investigations revealed that the strong LSPR effect of Au facilitated the transfer of electrons to the Pd surface to make the surface negatively charged and suitable for the activation of aryl halides. The formed electropositive Au nanoparticles were converted to Au0 by accepting the photo-induced electrons from pristine UiO-66-NH2 and made available only holes at VB for the activation of phenylboronic acid. Among all the synthesized photocatalysts (1 : 2), Au/Pd@UiO-66-NH2 showed the highest activity (>99%) with TOF = 426 h−1 in an EtOH/H2O medium towards the SMC reaction, and the highest activity of this catalyst was supported by the electron gas model, LSPR effect (UV-vis) and active species separation (PL) analysis. The bimetallic noble nanoparticle-anchored UiO-66-NH2 not only expands the synthesis scope of C–C coupling by the SMC reaction under ambient conditions but will also inspire the further exploration of the activation of various reactants towards a wide range of organic transformation reactions.

Exploiting the advantageous science of layered architectures, herein graphene oxide (GO) and a ZnCr-layered double hydroxide (LDH) have been united together and further modified by Au–Pd noble metal nanoparticles (NPs) to design a highly efficient novel GO/LDH@AuPd hybrid photocatalyst. The synthesis of this hybrid composite was carried out via the in situ nucleation of the ZnCr LDH over the surface of GO sheets, subsequently followed by the photo-deposition of bimetallic alloyed NPs and the reduction of graphene oxide (GO) to reduced graphene oxide (RGO) under light illumination. The successful formation of a GO/LDH@AuPd hybrid material was evidenced via XRD, UV-vis spectroscopy, TEM and XPS analysis. Here XPS techniques were employed to assess the electronic contribution of LDH towards the electron density on the noble metal through the GO surface during the photoreduction process. TEM images confirmed that bimetallic NPs are well dispersed on the LDH as well as over the GO surface. Moreover, the significant quenching of the PL intensity and the smaller arc radius of EIS measurements of an active AuPd alloyed sample demonstrate effective charge separation leading to superb photocatalytic activity. Here, an energy saving and green synthesis method was adopted by utilizing (i) visible-light active Zn–Cr-LDH nanoplates, (ii) SPR-effective gold NPs, (iii) the channelling features of GO, (iv) the charge heterogeneity of the AuPd alloy and (v) the efficiency of palladium towards the C–C coupling reaction, which made the catalyst more powerful in terms of enhancing the photocatalytic Suzuki coupling reaction compared to various chemical agents at high temperatures. The existence of Au enhances the abilities of Pd synergistically together with GO/LDH in the presence of visible light, boosting Suzuki coupling reactions. The Suzuki coupling product yield, i.e., biphenyl, is around 99.5% over the GO/LDH@AuPd composite, which is about 1.9 times higher than a single metal loaded GO/LDH composite. The enhanced catalytic activity resulted from the electron transfer pathways of LDH → Au → Pd and LDH → RGO → Au → Pd in the hybrid nanoarchitecture. We believe that this novel approach can lead to stable heterogeneous photocatalysts for other reactions with high activities.

Design and facile fabrication of a magnetically separable hetero-structure photocatalyst as well as an adsorbent having dual green benefits towards energy conversion and pollutant remediation are quite indispensable in the current scenario. In this regard, a composite of citrate capped Fe

The present research reports the synthesis of two-dimensional (2D) sheet/flake-like nanostructures of crystalline carbon modified TiO

Environmental pollution and energy scarcity is a major issue of the current scenario which forbear the progress of developing world. To overcome these problems towards a sustainable future, the utilization of sunlight by means of photocatalysis can be regarded as a best and suitable pathway. To validate this purpose, design and development of efficient heterogeneous photocatalyst for harvesting solar energy should be the major research concern for scientific community. In this regard herein, we have prepared a series of stable and efficient CoTiO

Photocatalytic organic transformations driven by functionalised metal organic frameworks (MOFs) are a green perspective for fine chemical synthesis. In the class of highly porous materials, MOFs are unparalleled in their degree of tunability and structural diversity and range of physical and chemical properties such as large surface area, permanent porosity, large void volumes, and framework flexibility, because of which they can act as a sustainable alternative for inorganic semiconductors. MOFs are the latest class of ordered porous solids being intensively studied as a novel class of hybrid organic–inorganic materials as nanophotocatalysts in the field of chemistry, materials science, chemical engineering, etc. Although the photocatalytic application of MOFs is still in the early stages compared with their other applications such as gas storage, separation, and heterogeneous catalysis, the currently available results have revealed that functionalised MOFs are very active as photocatalysts. The present review aims to discuss the various synthetic methods, post-synthetic modifications, MOF catalysed organic reactions and proposed mechanistic pathways for photoinduced organic transformations.

The abolition of environmental pollutants and production of hydrogen (H

Architecting a selective as well as high yielding catalyst has always been a challenge. Porous coordination polymers (PCPs) or popularly perceived as metal organic frameworks (MOF) are well endowed with tunable porosity, high specific surface area and easy functionalization as they are being constructed with plethora of possibilities; varying linker geometry, connectivity and functional groups along with inorganic secondary building unit (SBUs) having diverse topologies; making MOFs an extremely versatile inorganic–organic hybrid complexes for various emerging applications. Yet conventional MOF based materials are deficit in obtaining desired functionality and selectivity in a single crystal entity, hence to circumvent this setback, Inter-MOF Hybrid (IMOFH) compounds are explored for introducing advanced functionality in a single MOF crystal and this review intends to highlight the recent advances on IMOFH core–shell type architectures as an emerging class of hierarchical and multi-functional hybrid. In addition to it this review epitomizes a holistic exploration of rational design involving lattice choices, synthetic routes including forefront applications like; heterogeneous catalysis, adsorption and photocatalysis by IMOFH core–shell materials.