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Photocatalytic hydrogen production and pollutant degradation using a heterogeneous photocatalyst remains an alternative route for mitigating the impending pollution and energy crisis. Hence, the development of cost-effective and environmentally friendly semiconducting materials with high solar light captivation nature is imperative. To overcome this challenge, α-MnO2nanorod (NR)-modified MOF UiO-66-NH2(UNH) was prepared via a facile solvothermal method, which is efficient toward H2evolution and oxy-tetracycline hydrochloride (O-TCH) degradation. The field-emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HR-TEM) results of the α-MnO2@UNH (MnU) hybrid reveals its nanorod embedded in MOF matrix, and the X-ray photoelectron spectroscopy (XPS) result confirms the interaction of UNH moiety with α-MnO2NRs. Additionally, the outstanding separation of photogenerated excitons and the charge-transfer efficacy are further validated by photoluminescence (PL), time-resolved photoluminescence (TRPL), electrochemical impedance spectroscopy (EIS), and transient photocurrent analysis, which are the key causes for photoactivity augmentation in the MnU composites. The MnU-2 composite shows a superior O-TCH degradation efficiency of 93.23% and an excellent H2production rate of about 410.6 μmol h–1upon light irradiation. This study provides significant evidence in favor of the suggested mediator-free S-scheme-adapted charge migration path, and it effectively explains the enhanced exciton separation leading to extraordinary catalytic efficiency of the proposed composite.

Hydrogen and oxygen evolution via photocatalytic water splitting remains the quintessential alternative to fossil fuels. Photocatalysts must be sufficiently robust, competent, and productive toward harnessing sunlight in order to utilize the solar spectrum for maximal photocatalytic output. Herein, we have fabricated the MgIn2S4/UiO-66-NH2composite via a facile solvothermal route and have determined its efficacy toward light-induced H2and O2generation reactions through water splitting with the aid of different sacrificial agents. Initially, the formation of pristine and composite materials was ascertained by PXRD, FTIR, etc. Moreover, with the aid of sophisticated morphological characterization techniques (FESEM and HRTEM), the intricate interaction between MgIn2S4and UiO-66-NH2was revealed. Additionally, the XPS studies suggested the effective interaction between the individual components with binding energy shifting suggesting the transfer of electrons from Zr-MOF to MgIn2S4. The PL and electrochemical aspects supported the effective photogenerated charge segregation in the prepared composite leading to superior photocatalytic outputs. Amidst the prepared composites of (3, 5, and 7 wt %) MgIn2S4/UiO-66-NH2, the 5 wt % or UM-2 composite displays optimal H2and O2evolution performances of 493.8 and 258.6 μmol h–1(4-fold greater than for pristine MgIn2S4and UiO-66-NH2), respectively. The nanocomposite’s enhanced performance is indeed a consequence of the coadjuvant interaction among pristine UiO-66-NH2and MgIn2S4components that transpires via the Z-scheme-mediated charge transfer by enabling facile exciton segregation and channelization. Moreover, the composite inherited the remarkable framework stability of parent Zr-MOF, and the MgIn2S4insertion had a negligible impact on the framework integrity. This work will offer a valuable model for developing robust Zr-MOF-based nanocomposite photocatalysts and evaluating their superior performance toward photocatalytic water redox reactions.

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 O2evolution 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-NH2MOF through a facile hydrothermal technique and evaluated its efficiency toward photocatalytic H2and O2evolution 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 MoS2as 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 MoS2on the active surface of UiO-66-NH2by the ionic interaction between Zr–O and S/Mo. Among the synthesized photocatalysts (3 wt %) MoS2/UiO-66-NH2shows the optimum outcome toward H2and O2evolution, 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-NH2and MoS2, respectively). The superior performance obtained by the composite is due to the synergistic effect of pristine UiO-66-NH2and MoS2which 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.

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 H2production 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 H2production. 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 H2evolution.

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 viathe in situnucleation 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 viaXRD, 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.

In an alternative approach to mitigate the impending energy crisis, the photocatalytic production of H2O2and H2via semiconducting materials has currently attracted unprecedented research attention. In this study, NixPynanoparticles modified with a ZIF-8 MOF-derived C/N–ZnO (CNZ)/B-doped g-C3N4(BCN) nanohybrid were fabricated via a facile calcination-phosphidation strategy. Significantly, it was uncovered that NixPyacts as a robust visible-light-responsive cocatalyst that further promotes excitons’ antirecombination that are generated via the Z-scheme-based binary hybrid (CNZ/BCN). Hence, the photocatalyst ZIF-8-derived CNZ/BCN-NixPyexhibited intriguing results when subjected to photocatalytic H2O2production (2873.46 μmol h–1g–1), which is approximately 2-fold higher than binary CNZ/BCN (1:1). Meanwhile, this optimized structure delivers an improved H2evolution rate of 12,723 μmol h–1g–1. The significantly enhanced photocatalytic efficacy of the ternary hybrid was mostly related to the intricate interfacial contact between the Z-scheme heterojunction constructed by CNZ and BCN, which was substantiated by different characterization techniques. Moreover, the artful integration of the NixPycocatalyst into the binary hybrid further promoted the photogenerated charge separation and mobilization of photoexcitons and provides more surface reactive sites for photocatalytic reactions. Besides this, the synergistic effect of oxygen vacancies increases the transmission rate of photoexcitons and restrains the electron–hole recombination process. The enormously enhanced photocatalytic activity and better stability endowed a promising potential for the CNZ/BCN-NixPycomposite towards photocatalytic applications. This research work not only sheds light on the substantial role of the NixPycocatalyst in decreasing the dosages of noble metal cocatalysts for photocatalytic application but also reveals avenues to construct MOF-derived ternary heterostructures for photocatalytic energy conversion applications.