Real-time monitoring of ammonia (NH3) is essential for environmental safety, industrial process control, and biomedical diagnostics; however, achieving high sensitivity, fast response, and long-term stability in chemiresistive sensors remains challenging. In this study, a microstructural engineering strategy is demonstrated for ZnO thin films deposited via the successive ionic layer adsorption and reaction (SILAR) technique, where controlled variation of precursor solution volume (25–100 mL) enables systematic tuning of crystallinity, defect density, and grain connectivity. Structural analysis reveals that increasing the precursor volume enhances crystallite size (≈14.5–19.3 nm), reduces dislocation density and microstrain, and produces dense, well-connected grain architectures. Consequently, the optimized ZnO thin film exhibits reliable NH3 sensing at room temperature over a concentration range of 50–250 ppm, with fast response times of 3.6–7.5 s and recovery times of 6.6–14.6 s. The sensor demonstrates good selectivity toward NH3 over CO, CO2, H2, and SO2, stable operation under relative humidity of 35–70%, and excellent long-term stability with negligible degradation over 50 days. Steady-state photoluminescence shows characteristic defect-related emissions at ∼465 nm and ∼508 nm, while time-resolved measurements reveal biexponential decay with comparable lifetimes across all samples, indicating similar recombination pathways. The enhanced sensing performance is attributed to the combined effects of surface chemisorbed oxygen species and reduced grain-boundary resistance, enabling efficient electron percolation and reversible surface redox reactions. These results establish controlled microstructural engineering of undoped ZnO thin films as a simple and scalable route to high-performance NH3 gas sensors.

Herein, a hydrazone-linked covalent organic framework (TFPB-OD) was constructed using 1,3,5-tris(4-formylphenyl)benzene (TFPB) and oxalyldihydrazide (OD) monomeric units. Co(II) was embedded via post-synthetic modification, yielding a well-coordinated, nitrogen- and oxygen-rich porous framework, Co(II)-TFPB-OD, for the synthesis of an active Lewis acidic center-containing heterogeneous catalyst. Both metal-containing and metal-free hydrazone-linked COFs were thoroughly characterised using different characterization techniques, such as FT-IR spectroscopy, PXRD, BET surface area analysis, XPS, TGA, SEM, and TEM, to establish a comparative study. These techniques confirmed the successful formation of a crystalline, micro-porous Co(II)-TFPB-OD COF with Co(II) distributed uniformly with a surface area of around 212.65 m2 g-1. This metal COF was used as a catalyst for the formation of cyclic carbonate from oxiranes via thermal CO2 fixation and oxazolidinone via three-component cyclization between oxiranes, amines and CO2. Both reactions were carried out under solvent-free conditions using atmospheric CO2 pressure. For cyclic carbonate, a substrate yield of up to 96% was achievable, and for oxazolidinone, the yield varied up to 82%. The catalyst exhibited excellent recyclability up to 5 consecutive cycles, and the reused COF was characterized again via PXRD, SEM, BET surface area analysis, FT-IR spectroscopy, and XPS to confirm the recyclability and stability of the hydrazone-linked COF.

The quest for high-performance, cost-effective photodetectors has driven the exploration of doped semiconductor thin films with tunable optoelectronic properties. In this study, Fe-doped CdS thin films with varying Fe concentrations (0 %, 2 %, 4 %, and 6 %) were synthesized via spray pyrolysis to investigate the impact of Fe doping on their structural, optical, dielectric, and photodetection properties. X-ray diffraction spectra confirmed the retention of the hexagonal wurtzite structure, with reduced crystallite size and increased lattice strain upon Fedoping. Raman spectroscopy revealed enhanced LO phonon modes and lattice distortion, while scanning electron microscopy and EDX mapping confirmed Fe-induced morphological changes and uniform dopant distribution. UV-Vis absorption studies demonstrated bandgap narrowing from 2.42 eV to 2.33 eV (at 4 wt% Fe), improving visible-light absorption, while photoluminescence analysis indicated suppressed carrier recombination at optimal doping. Dielectric measurements showed enhanced polarization stability and reduced energy dissipation, confirming improved charge transport. Photodetector investigations revealed that 4 wt% Fe-doped CdS exhibited the best performance, with high responsivity (0.34 A/W), detectivity (2.9 x 1011 Jones), EQE (110 %), and fast response/recovery times (1.7 s/0.5 s). Long-term stability tests over 100 days confirmed consistent photodetector performance. These results establish 4 wt% Fe-doped CdS thin films as promising candidates for visible-light photodetectors, offering a balance of sensitivity, stability, and scalability for optoelectronic applications.

The persistent presence of organic dyes and antibiotic residues in wastewater poses a critical environmental challenge, driving the need for sustainable photocatalytic solutions under solar irradiation. In this study, plasmon-enhanced Au-decorated ZnO nanosheets (Au@ZnO) were rationally designed with engineered Schottky junctions at the metal-semiconductor interface for visible-light-driven degradation of methylene blue (MB), Congo red (CR), and tetracycline (TC). The 2D ZnO nanosheets, synthesized via hydrothermal methods and in situ decorated with Au nanoparticles, offer an enlarged surface area and uniform Au dispersion, ensuring strong interfacial contact. X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) confirmed lattice expansion and homogeneous Au dispersion, while X-ray photoelectron spectroscopy (XPS) revealed strong electronic coupling and the presence of oxygen vacancies and metallic Au-0. Optical studies (UV-Vis DRS) revealed an extended absorption edge and enhanced visible-light response due to localized surface plasmon resonance (LSPR). The formation of a Schottky junction at the Au-ZnO interface was validated by Mott-Schottky plots, and electrochemical impedance spectroscopy (EIS), all indicating improved charge separation and transport. Under natural sunlight, the optimized 2.00 wt% Au@ZnO catalyst achieved up to similar to 98 % and 91 % degradation of MB and TC, respectively, within 80 min, exhibiting pseudo-first-order kinetics and superior stability across multiple cycles. Radical scavenging experiments confirmed the involvement of hydroxyl radicals (center dot OH), as key active species. This work highlights a synergistic interplay of 2D morphology, LSPR-driven light harvesting, and Schottky barrier-assisted charge separation, providing a robust strategy for solar-powered environmental remediation.

Pr-doped ZnO nanoparticles were synthesized and systematically investigated for the photocatalytic degradation of methylene blue (MB) under natural sunlight. Structural and spectroscopic analyses confirmed successful Pr3+ incorporation without secondary phases, with lattice distortion and oxygen vacancy formation enhancing surface reactivity. Notably, Pr doping induced a moderate bandgap widening due to the Burstein-Moss effect; however, this was offset by improved charge carrier dynamics, as evidenced by photoluminescence quenching and reduced charge transfer resistance in EIS analysis. Among the compositions, 5 wt% Pr-ZnO exhibited the highest photocatalytic activity, achieving 91.6% MB degradation and a 3.6-fold increase in reaction rate over undoped ZnO. Scavenger experiments identified hydroxyl and superoxide radicals as dominant species, while optimization studies confirmed 20 mg/L catalyst loading and 10 ppm dye concentration as optimal. The catalyst retained over 82% efficiency after four reuse cycles with preserved crystallinity. This work provides new insight into how rareearth doping can simultaneously modulate the electronic structure and interfacial charge behavior of ZnO, offering a robust design strategy for visible-light-driven photocatalysts in environmental applications.

Countries like Saudi Arabia receive abundant sunshine with exceptionally high solar irradiance. High temperatures in desert regions and the sunray angle dependence of solar modules are some of the key challenges of conventional solar cells. Dye-sensitized solar cells present a compelling alternative with the simple cell design and use of non-toxic materials without angle dependence, but their performance hinges on the solid redox mediators used for dye regeneration. These mediators must have an electrical conductivity (σ25°C) of more than 10-4 S cm-1 with an activation energy of less than 0.3 eV for device application. Our work focused on novel solid Co(II/III) redox mediators using cobalt complexes and LiClO4 in different matrices: pure PEO (an abbreviation for poly(ethylene oxide) with its redox mediator as M1), a [PEO-SN] blend (M2A and M2B with ethylene oxide to lithium ions molar ratio of 112.9 and 225.8, respectively), and pure SN (an abbreviation for succinonitrile with its redox mediator as M3). Impedance spectroscopy was the key technique, showing M1 and M2 behave like a mediator explainable with an (R1-C)-type circuit, while M3 is explainable with an (R1 - [R2‖C])-type circuit. M3 achieved the highest value of σ25°C with 2 × 10-3 S cm-1, while M1 had the lowest σ25°C, 3 × 10-5 S cm-1. M2 achieved an optimal balance with σ25°C of 4 × 10-4 S cm-1 (M2A) and 1.5 × 10-4 S cm-1 (M2B). M2 exhibited a remarkably low pseudo-activation energy of 0.042 eV and a Vogel-Tammann-Fulcher behavior ideal for consistent performance across temperatures. In contrast, M1 and M3 showed higher Arrhenius-type activation energies (>0.74 eV) in their solid states. These results correlated with those of the XRD, FT-IR spectroscopy, XPS, SEM, DSC, and TGA analyses. Ultimately, the [PEO-SN] blend emerges as a robust matrix, enabling the combination of high conductivity and low activation energy needed for a durable device in harsh environments.

An imidazole-linked covalent organic polymer (COP) was synthesized using a combination of 2,4,6-triformylphluroglucinol and 3,3 '-diaminobenzidine (TPDB). To enhance the photocatalytic activity of the synthesized COF, rhodium was grafted as Rh(iii) for post-synthetic modification (PSM). The structural and photophysical properties of the synthesized Rh(iii)-embedded covalent organic polymer (Rh(iii)@TPDB) and TPDB COP were explored using different characterization techniques (PXRD, BET, XPS, EIS, etc.). With a band gap of 1.58 eV, Rh(iii)@TPDB shows exceptional photo activity. The efficiency of Rh(iii)@TPDB was established for both photocatalytic CO2 fixation and CO2 reduction. The N-formylation of amines via photocatalytic CO2 fixation under mild conditions was performed, and a maximum isolated yield of 89% was achieved in a reaction span of 12 h. In the course of the photoreduction of CO2 using water as a solvent and Rh(iii)@TPDB as the photocatalyst for 4 h under visible light, HCOOH (1625 mmol gcat-1 h-1) and CH3OH (267 mmol gcat-1 h-1) were formed at a significant production rate. The catalyst was heterogeneous in nature. The heterogenicity of the Rh(iii)@TPDB catalyst was evaluated via a leaching test. The Rh(iii)@TPDB catalyst was recycled for up to five cycles without an appreciable loss of activity. The structural integrity and stability of the recycled catalyst were examined using different characterization techniques (FT-IR, SEM, TEM etc.).

Sensitive and selective detection of ammonia (NH3) at room temperature remains a key challenge for environmental monitoring. ZnO thin-film chemiresistive sensors were fabricated via Successive Ionic Layer Adsorption and Reaction (SILAR) using a reaction-time engineering approach (10-40 s). Structural analysis confirmed hexagonal ZnO with a dominant (002) orientation, while reaction time modulated crystallite size, microstrain, and defect density. The optimized 30 s film exhibited a favorable combination of crystallinity, accessible granular morphology, and defect-assisted carrier dynamics, supported by reduced photoluminescence (PL) intensity and shorter carrier lifetime (tau avg approximate to 1.80 ns), indicating improved non-radiative charge transfer. The sensor demonstrated reliable, concentration-dependent NH3 detection (50-250 ppm), with rapid response and recovery times of 5.7 s and 15.1 s, respectively, at 250 ppm, along with excellent selectivity over interfering gases. Stable operation under varying humidity conditions and reliable repeatability over 50 days were observed. These results establish reaction-time engineering as a simple, scalable, and dopant-free strategy for high-performance ZnObased environmental sensors.

Controlling thin film growth parameters is critical for tailoring the functional properties of metal oxide semiconductors. This study investigate the influence of adsorption time during the successive ionic layer adsorption and reaction (SILAR) process on the structural, optical, photophysical, and ammonia (NH3) gas sensing properties of zinc oxide (ZnO) thin films. Precursor immersion time was systematically varied (5-20 s) to engineer microstructure and enhance device performance. Structural analysis via X-ray diffraction (XRD) and Raman spectroscopy showed that increasing adsorption time promotes crystallinity, enlarges crystallite size (from 16.56 to 27.88 nm), and reduces microstrain and defect density. Field-emission scanning electron microscopy (FESEM) revealed a morphological evolution from granular clusters to vertically aligned nanorods, increasing active surface area. Optical absorption spectra demonstrated a redshift in the band edge and a narrowing of the optical bandgap from 3.10 to 2.50 eV due to sub-bandgap defect states. Steady-state and time-resolved fluorescence spectra indicate enhanced radiative recombination and shorter carrier lifetimes, with the 20 s sample showing a lifetime of 548 ps. Notably, the 15 s film achieved outstanding NH3 sensing performance, with rapid response (5.7 s), fast recovery (10.1 s), high selectivity, and humidity tolerance over 50 days. This work demonstrates that adsorption time in SILAR cycles can be systematically tuned to control ZnO film morphology, defect states, and photophysical dynamics. The optimized 15 s condition delivers record-high NH3 response (5270 at 50 ppm) with long-term stability, establishing adsorption time as a simple yet powerful parameter for reproducible, highperformance ZnO gas sensors.

Since spintronic devices can operate at far higher speeds, with less power consumption, and with unlimited durability, it is a developing subject that might eventually replace traditional electronics. Double perovskites have strong spin polarization ferromagnetism, which makes them ideal materials for spintronics. Density Functional Theory has been used in the current study to examine the structural, optoelectronic, magnetic, and thermoelectric characteristics of K2CuCrCl6 and K2CuCrBr6. PBE-sol is used to compute exchange correlation potential, and mBJ potential is used to measure bandgap accurately. The two materials demonstrate a cubic structure and thermodynamic stability, as demonstrated by their respective volume optimization and negative formation energy values. Materials that are ferromagnetic can be identified by their exchange constant values and spin-based energy-volume optimization. It has been noted that the primary contribution in net magnetic moment resulting from exchange splitting and the source for ferromagnetism is the 3-d states of Cr. Additionally, studies of band structure and density-of-states reveal that materials are semiconducting, having indirect bandgap values of 1.3 eV and 1.2 eV for K2CuCrCl6 and K2CuCrBr6, respectively, and substantial ultraviolet absorption in the optical spectra of the materials. In conclusion, the study of thermoelectric characteristics involves the assessment of thermal and electrical conductivities, Seebeck coefficient, power factor, and figure of merit (ZT). K2CuCrCl6 and K2CuCrBr6 both exhibit a high ZT, with values of 0.77 and 0.71, respectively. The findings of electronic and magnetic characteristics of K(2)CuCrZ(6) (Z = Cl, Br) reveal that these investigated materials hold significant potential for applications in advanced technologies like spintronic and optoelectronic devices in which their stability and tunable magnetic behavior could be leveraged to develop versatile and more efficient components.

Herein we have described the preparation and UV photodetection properties of Antimony (Sb) doped Indium Sulfide (In2S3) thin films. The nebulizer spray pyrolysis method was used to deposit the undoped and Sb-doped In2S3 thin films onto glass substrates at 350 degrees C. The X-ray diffraction (XRD) analysis verified that all deposited films exhibited the cubic phase beta-In2S3 structure, with the highest crystallinity observed in the 3 wt% Sb-doped film. The morphological analysis showed densely packed, relatively larger grains in the 3 wt% Sb-doped In2S3 thin film. From UV-Vis investigation, it was observed that Sb doping enhanced optical absorption. The key parameters of the photodetectors were determined by Current-Voltage and Current-Time measurements. Among the fabricated photodetectors, the 3 wt% Sb-doped In2S3 thin film exhibited remarkable performance, with calculated Responsivity (R) of 1.020 A/W, Detectivity (D*) of 32.5 x 1010 Jones, and External Quantum Efficiency (EQE) of 346 %. The photo-response investigation provided rise and fall times of 0.43 s and 0.26 s respectively, for the 3 wt% Sb-doped sample. Additionally, the stability test demonstrates the durability, reliability and suitability of the photodetectors for long-term applications. The remarkable enhancement in photodetector properties achieved through Sb doping highlights the exceptional quality and potential of the 3 wt % Sb-doped In2S3 thin films, setting a new standard for performance in advanced UV detection applications.

A novel hierarchical NiCo2O4/MoS2@rGO composite was synthesized to improve the electrochemical properties of supercapacitors. The nanocomposite combines the enhance capacity of NiCo2O4, the excellent ion storage capability of MoS2, and the conductive support of rGO, addressing challenges related to energy density, cycle life performance. The NiCo2O4/MoS2@rGO nanocomposite exhibits an impressive specific capacitance of 1696 F g−1 at 1 A g−1, and the resulting asymmetric supercapacitor (NiCo2O4/MoS2@rGO//AC) demonstrates an increased energy density of 56.45 Wh kg−1 and a power density of 750 W kg−1. Moreover, the composite retains 95.2

This study uses jet nebulizer spray pyrolysis for photodiode applications to prepare PbS films with varying Yttrium (Y) doping concentrations (0, 1, 3, and 5 wt%). XRD results reveal that Y-doped PbS films have a cubic structure, with grain size increasing as Y concentration rises, signifying successful Y incorporation into the PbS lattices. FESEM analysis shows the thin films have a triangular, nanostructured, crack-free surface. XPS confirms the presence of PbS, and Y. At the same time, optical studies indicate improved performance with Y doping, with the 3 % Y-doped film demonstrating outstanding photosensitivity (2895.21 %) and response of 208.33 mA/W, highlighting its potential for optoelectronic applications.

This work studies the development of windows of harmonious instability in negative refractive material. After taking into account the fundamental need to monitor instability, such as self-phase modulation and group velocity spreading, we first examine the effects on the gain spectrum of fourth and third-order dispersals, cubic-quintic nonlinearity, higher-order nonlinear dispersions, self-steepening, and detuning parameter. Furthermore, in metamaterials with the aforementioned nonlinear effects, we investigate the influence of an adjustable nonlinear saturation effect over the modulational instability. Tunable modulation instability (MI) gain spectrum formation results from the tunable material parameters made possible by the engineering freedom offered by metamaterials. As a structure is operated at high incident power, generally exceeding the medium's saturation inception, the SNL becomes a robust case. The nonlinear saturation window with negative index material can also produce adjustable instability gain spectrum formation. More methods for forming solitons and ultrashort pulses with desired parameters can be achieved with this tunable gain spectrum. The numerical approach validates the analytical prediction that came from the linear stability study.

The potential of spinel chalcogen compounds in thermoelectric and optoelectronic applications has attracted a lot of attention in recent years. Here, we use the DFT-based WIEN2k algorithm to conduct a thorough investigation of the electronic, magnetic, structural, mechanical, optical, and transport responses for HgGd2(S/Se)4 spinels. Using energy versus volume graphs and Delta Hf calculations, the ground state for thermodynamic stability and crystal structure of the material are determined. Our analysis, which includes the Poisson and Pugh ratios, indicates that the composition under study is ductile. The TB-mBJ method is used to examine band gaps, which reveals compounds under investigation as a semiconductor having direct band properties. In particular, the computed band gap values for HgGd2S4 and HgGd2Se4 are 2.2 and 1.8 eV, respectively. Furthermore, examination of the optical characteristics and transport response highlights potential of abovementioned compounds for various optoelectronic and thermoelectric uses. However, from a broader perspective, our calculations indicate that the band gap of the materials are suitable for UV irradiation.

A challenging but very important task is the development of efficient and cost effective non-noble metal based bifunctional electrocatalysts with excellent kinetics for overall water splitting. Improving the catalyst’s electronic structure, optimizing intermediate adsorption, and enhancing charge transfer kinetics are crucial for enhancing reaction efficiency. In this study, we prepared three-dimensional structured V-doped CoP grown in situ on MXene by one-step hydrothermal and controlled phosphorylation (defined as V-CoP/MXene@NF). The V doping not only optimises the electronic conductivity, but also creates a strong synergistic effect between the MXene and V-CoP components, enriching the active sites of the catalysts. The V-CoP/MXene@NF electrocatalyst can achieve a current density of 10 mA·cm−2 in 1.0 M KOH solution, with overpotentials of 78 and 223 mV for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER), respectively. For overall water splitting, we used the catalyst as an anode and cathode assembly in an electrolytic cell, which could drive a current density of 10 mA·cm−2 with an overpotential of only 1.56 V and excellent durability. This work provides new ideas for designing novel MXene-based non-noble metal bifunctional electrocatalysts.

The photocatalytic ability of bare ZnO is less sufficient owing to a weak separation rate of electron-hole and weak exploitation of solar energy. In this context, mesoporous ZnO nanosheets were constructed through a hydro-thermal approach utilizing hexadecyltrimethylammonium bromide (HTAB) as a template. Then, CuAl2O4 NPs at different concentrations were grown in-situ onto mesoporous ZnO nanosheets to build mesoporous CuAl2O4/ZnO photocatalysts. XRD and TEM indicated the formation of the spinel cubic CuAl2O4 (10 nm) with uniform distribution on the hexagonal structure of ZnO sheets. The synthesized CuAl2O4/ZnO nanocomposites were assessed for tetracycline (TC) photodegradation under visible illumination. The optimal p-n heterojunction 12%CuAl2O4/ ZnO photocatalyst revealed excellent photocatalytic efficiency of 100 % after 90 min for TC degradation. The 12%CuAl2O4/ZnO nanocomposites showed the optimum rate constant of 0.0739 min-1, which was about 49.75 folds larger than that of bare ZnO (0.0015 min-1). The superior photocatalytic activity of CuAl2O4/ZnO nano-composite was interpreted by its excellent harvest of visible light, synergistic effects, mesopores structure characteristics, effective separation of photocarriers, larger surface area, smaller particle size, proper bandgap energy, and larger pore volume. The stability and reusability of the photocatalyst showed superior photocatalytic ability (94 %) during five consecutive cycles. This work provides the design novel of p-n heterojunction-based photocatalyst to be a valuable reference for photocatalytic degradation systems.

Constructing nonprecious metal electrocatalysts with good hydrogen evolution activity is crucial for the hydrogen evolution reaction (HER) in acidic media. The synergistic optimization of the water dissociation and hydrogen desorption steps presents a challenge for the HER. Here, we have synthesized phosphorus‐doped tungsten trioxide with oxygen vacancies(O V ) (P‐WO 3‐x ) using a simple but effective hydrothermal reaction followed by calcination annealing. Interestingly, the P‐WO 3‐x material exhibits unique characteristics that set it apart from conventional tungsten oxide‐based electrocatalysts. The introduction of O V and phosphorus doping creates an optimal structure that significantly improves the electronic properties and the catalytic sites. The O V enhance the material's ability to adsorb and activate water molecules, while phosphorus doping further modifies the electronic structure, facilitating more efficient hydrogen desorption. Meanwhile, the catalyst demonstrates a favorable urchin‐like morphology with excellent supportability. Remarkably, the P‐WO 3‐x electrocatalyst demonstrates excellent HER performance and excellent durability. We indicate that P‐WO 3‐x exhibits a small overpotential (122.68 mV at −10 mA cm −2 ), a low Tafel slope (74.97 mV dec −1 ), and excellent durability over 12 hours. This work presents a significant advance for the development of tungsten oxide‐based electrocatalysts with anion doping and O V for HER in acidic media.

Photocatalytic reduction of CO2 has garnered significant attention as a sustainable and clean process for producing fuels and chemicals. Various heterojunction-based photocatalysts are explored to effectively reduce CO2 to valuable chemicals. In this study, porous ZnO sheets are fabricated through a hydrothermal process using polyvinylpyrrolidone as a pore builder. Moreover, Li2MnO3 NPs were incorporated into the ZnO nanosheet via the impregnation method with varying Li2MnO3 contents (5-20 %). Li2MnO3 NPs are uniformly dispersed on the porous ZnO sheets, which enhances the photocatalytic performance. The resulting Li2MnO3/ZnO photocatalyst demonstrates an improved CO2 photocatalytic reduction to CH3OH under visible illumination. The 15 % Li2MnO3/ZnO photocatalyst achieves a maximum formation rate of CH3OH at approximately 156.04 mu mol g-1h-1, which is 15.85 times greater than that of bare ZnO. Furthermore, the photocatalytic ability after five cycles of reactions remains remarkably stable due to its exceptional stability during CO2 reduction. The enhanced photocatalytic performance of the Li2MnO3/ZnO photocatalyst is attributed to the modification of the bandgap structure, strong visible light response, improved CO2 adsorption, high electronic reduction capability, and effective charge transport capacity. This work contributes to the novel design of highly effective S-scheme mechanisms for the photoreduction of CO2.

The potential applications of covalent organic frameworks (COFs) in the field of photocatalysis are constrained by the fast recombination rate of the photoinduced carriers and their limited visible light absorption capacity. Design of Z-scheme heteroframework utilizing COFs is believed to be an innovative and effective approach to assist the charge separation efficacy and improve the photocatalytic activity of the materials. Herein, the imine-based 2D COF (referred to as TP-TAPM COF) and TiO2 were effectively coupled together by covalent bonding using a simple solvothermal approach to construct a novel heterojunction TiO2/TP-TAPM photocatalyst. The resulting TiO2/TP-TAPM heterostructure was well characterized by a sequence of experimentations to investigate the compositional, structural, and morphological characteristics. Interestingly, the as-synthesized hybrid photocatalyst was applied for the first time to efficiently reduce CO2 to CH3OH as well as N-2 to NH3 under visible light illumination at ambient reaction conditions without the need of specific organic scavengers and cocatalysts. Using the TiO2/TP-TAPM hybrid photocatalyst (8 mg), a substantially higher yield of methanol was produced with a formation rate of 281.25 mmol g(cat)(-1) h(-1) after 4 h of visible light irradiation. Whereas, the generation rate of NH4+ was found to be 747 mu mol L-1 h(-1) after irradiation for 5 h using 5 mg of as-synthesized heterojunction photocatalyst. The development of a covalent interaction in the 2D-2D heterojunction between COF and TiO2, mostly as a result of their close interfacial contact, can be attributed to the greatly improved photocatalytic efficiency. Hence, the constructed 2D-2D-layered structure offers a high contact area, which substantially facilitates the separation and transportation of photogenerated charge carriers, boosts light absorption, and enhances photocatalytic activity. This work sheds light on the development of a promising approach for the artful integration of organic materials (COFs) with inorganic semiconductors into a single hybrid with a 2D-2D interface as effective photocatalysts for CO2 reduction as well as N-2 fixation, holding significant implications for extensions to other material systems.