This study investigates the synergistic potential of a novel heterojunction photocatalyst for methyl orange degradation. The photocatalyst comprises iron tungstate (FeWO 4 ) and graphitic carbon nitride (g-C 3 N 4 ), engineered to exploit the distinct properties of each component for enhanced photocatalytic activity. The research systematically evaluates the performance of the synthesized FeWO 4 /g-C 3 N 4 composite in degrading methyl orange, with an emphasis on optimizing catalytic efficiency. The photocatalyst was characterized using advanced techniques, including Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) to elucidate its structural and morphological properties. Key parameters such as loading concentrations were optimized to assess their influence on the photodegradation efficiency. Among tested compositions, 1.0 wt% FeWO 4 /g-C 3 N 4 achieved the highest degradation efficiency of MO at 78.04% within 180 minutes under UV irradiation. The heterojunction structure promoted effective charge separation, and further enhanced visible-light response. These results demonstrate the catalyst’s potential for sustainable water purification applications.

Abstract Driven by rising global energy demand and environmental concerns over fossil fuels, photocatalytic water splitting for solar-driven hydrogen production has gained prominence. Herein, we propose a novel GeC/B 2 SSe van der Waals (vdW) heterostructure. Employing the quantum ESPRESSO code based on density functional theory (DFT), combined with the HSE06 hybrid functional and DFT-D3 van der Waals correction, we conduct a comprehensive evaluation of its structural, electronic, optical, and transport properties, alongside its strain-tunable photocatalytic behaviour. The heterostructure exhibits only 3.75% lattice mismatch and is stabilized by weak vdW interactions, ensuring energetic, dynamic, and thermodynamic stability at room temperature. It is an indirect bandgap semiconductor (2.64 eV) with a Type-II band alignment, enabling spatial charge separation. A built-in interfacial electric field (2.47 eV) further suppresses electron–hole recombination. The band edges straddle the water redox potentials across the entire pH range of 1–14, fulfilling the thermodynamic criteria for universal overall water splitting. The system shows strong visible-light absorption with a peak absorption coefficient of 1.04 × 10 5 cm −1 at 3.03 eV and ultrahigh hole mobility (69276.91 cm 2 V −1 s −1 along the armchair direction), with mobility asymmetry between carriers reducing recombination. Under biaxial strain (–6% to +6%), the redox alignment is preserved, and tensile strains (+4% to +6%) notably enhance light absorption. These results establish GeC/B 2 SSe as a highly promising photocatalyst for solar hydrogen generation, offering a solid theoretical basis for future experimental development.

Semiconductor-based photo-redox catalysis offers a sustainable route for green organic synthesis, yet efficient C(sp3)-H bond oxidation remains challenging due to slow charge separation and limited surface reactivity. Here, we report a CsPCN (cesium doped polymeric carbon nitride)-Cs3Bi2Br9 heterojunction that promotes efficient charge separation while retaining strong hole oxidation capability of Cs3Bi2Br9 and superior oxygen and reactant activation ability of CsPCN. In situ experimental and theoretical studies confirm the photoelectron transfer pathway from Cs3Bi2Br9 to CsPCN driven by the interfacial electric field, empowering efficient spatial charge separation and high affinity and activation capability toward oxygen and reactants. As a result, the heterojunction exhibits efficient C(sp3)-H bond oxidation performance and broad substrate applicability under visible-light irradiation, achieving a conversion rate of ethylbenzene to acetophenone up to 8420 µmol g-1 h-1, 4.3 times higher than blank Cs3Bi2Br9 (1950 µmol g-1 h-1). This work demonstrates a rational heterostructure design strategy to couple charge separation with surface reactant activation for efficient lead-free perovskite based photocatalytic C(sp3)-H functionalization.

Abstract We report the influence of the deposition sequence of α-Fe 2 O 3 and TiO 2 layers on the photoelectrochemical (PEC) water-splitting performance of α-Fe 2 O 3 /TiO 2 heterostructured photoanodes. Hematite nanoparticles (NPs), synthesized via a co-precipitation method followed by calcination, together with commercial TiO 2 NPs, were employed to fabricate α-Fe 2 O 3 /TiO 2 photoanodes using a spin-coating approach. Linear sweep voltammetry (LSV) measurements reveal that the heterostructured photoanodes deliver significantly higher photocurrent densities than the corresponding single-layer electrodes, with a strong dependence on the layer deposition sequence. Specifically, at applied potentials below 1.65 V (vs. RHE), the FTO/TiO 2 /α-Fe 2 O 3 photoanode exhibits the highest photocurrent density. In contrast, at potentials above 1.65 V vs RHE, the FTO/α-Fe 2 O 3 /TiO 2 configuration becomes dominant, achieving a photocurrent density of up to 1.16 mA cm -2 at 1.8 V (vs. RHE), which is approximately 2.47, 5.04, and 12.89 times higher than those of the FTO/TiO 2 /α-Fe 2 O 3 heterostructured electrode and the single-layer FTO/α-Fe 2 O 3 and FTO/TiO 2 electrodes, respectively. Combined optical characterization and electrochemical impedance spectroscopy analyses indicate that the distinct PEC behaviors of the heterostructured photoanodes can be rationalized by their band alignment, applied-bias effects, and the role of interfacial trap states in charge separation and recombination processes.

ABSTRACT Covalent organic polymers (COPs) have emerged as promising photocatalysts for efficient solar‐driven conversion of energy into chemicals. However, it remains rare for COPs capable of effectively harvesting long‐wavelength visible to near‐infrared (L‐Vis‐NIR) light ( λ > 600 nm) to achieve these photochemical transformations. Here, two isomeric mesoporous Al‐Salen COP fibers are demonstrated as L‐Vis‐NIR‐responsive photocatalysts for efficient Griffith‐type oxygen activation to produce hydrogen peroxide (H 2 O 2 ). Both COPs achieve a high H 2 O 2 production rate of about 1607 µmol g cat −1 h −1 under irradiation of common domestic LED lights (680–690 nm, 3.18 mW cm −2 ) using 1,2,3,4‐tetrahydroisoquinoline as a sacrificial reagent with a high solar to chemical efficiency of about 5.0%. Their efficient L‐Vis‐NIR‐responsive photocatalytic performance is attributed to their narrow band gaps of about 1.5 eV, efficient charge separation facilitated by integrated electron‐donor (benzene ring) and electron‐acceptor (Al‐Salen Lewis acid site) structures, and a direct Griffith‐type photo‐activation mechanism for oxygen. No significant isomerism effect is observed in their photocatalytic performance, attributed to the similar photoinduced charge carrier behaviors mainly affected by the local Al‐Salen moieties rather than the topological structure. This study highlights isomeric Al‐based COPs as effective platforms for L‐Vis‐NIR photocatalysis and opens avenues for the development of Al‐based COP photocatalysts for diverse chemical transformations.

Abstract A visible-light-active nanohybrid photocatalyst comprising graphitic carbon nitride (g-C3N4) and arc-discharge produced multi-walled carbon nanotubes (MWCNTs) was synthesized via thermal polycondensation of melamine in the presence of varying MWCNT loadings (0.1–1 wt %). The structural, morphological, and optical properties of the resulting nanocomposites were comprehensively characterized using XRD, SEM, TEM, BET, PL, XPS, FTIR, and UV-DRS. The photocatalytic activity was assessed through the degradation of Rhodamine B (RhB) under visible-light irradiation. Among all compositions, the g-C3N4 hybrid containing 0.1 wt % MWCNTs demonstrated the highest photocatalytic efficiency, achieving 97% degradation of RhB within 90 minutes, surpassing that of pristine g-C3N4 (88%). The enhanced performance is attributed to improved photogenerated charge separation and prolonged carrier lifetimes facilitated by the 1D/2D heterojunction architecture, along with the favourable alignment of conduction and valence band edges. These findings highlight the synergistic effect of MWCNT incorporation in optimizing charge dynamics and broadening the visible-light utilization of g-C₃N₄-based photocatalysts.

In the present investigation, ZnO nanoparticles synthesized via a green route using Averrhoa bilimbi (ZnO B0 and B1) and Brassica oleracea (ZnO C0 and C1) extracts demonstrated distinct photocatalytic performance as a function of their structural and defect characteristics. X-ray diffraction and Williamson-Hall (W-H) analyses revealed that ZnO (B1) (synthesized with Averrhoa bilimbi fruit extract and calcined) exhibited a crystallite size of 44.8 nm and a moderate lattice strain of 0.0011, while ZnO (C1) (synthesized using Brassica oleracea var. botrytis leaf extract and calcined) exhibited a larger crystallite size of 58.6 nm and a relatively higher strain of 0.0015. These microstructural variations played a pivotal role in influencing the photocatalytic behavior under solar irradiation, as further supported by EPR and XPS analyses, which revealed a higher concentration of oxygen vacancies and defect states responsible for enhanced charge separation and activity. ZnO (B1) achieved the highest methylene blue (MB) degradation efficiency, attributed to its balanced defect concentration and strain-induced surface activity. In contrast, despite improved crystallinity, ZnO (C1) exhibited reduced activity, likely due to excessive lattice strain and oversaturation of defect sites, which promoted electron-hole recombination. Kinetic analysis based on the Langmuir-Hinshelwood model and thermodynamic evaluation further supported the structure-driven enhanced photocatalytic behavior of ZnO (B1). Overall, this study establishes, for the first time, a systematic correlation between Williamson-Hall microstructural parameters and the photocatalytic kinetic and thermodynamic behavior of green-synthesized ZnO nanoparticles.

Atom-centered electric multipole moments can be extremely useful in chemistry, as they enable the systematic mapping of a complex electrostatic problem to a simpler model. However, since they do not correspond to physical observables, there is no unique way to define them. In this study, we present an extension of the dynamically generated RESP charges (D-RESP) method, referred to as xDRESP, where atom-centered multipoles are computed from mixed quantum mechanics/molecular mechanics molecular dynamics simulations. We compare the ability of xDRESP charges to reproduce the electrostatic potential, as well as molecular multipoles, against the performance of fixed point-charge models commonly used in force fields. Moreover, we highlight cases where xDRESP atomic multipoles can provide valuable information about chemical systems, such as indicating when polarization plays a significant role, and chemical reactions in which xDRESP atomic multipoles can be used as an on-the-fly analysis tool to track changes in electron density.

The efficient conversion of light into chemical energy in water is often hindered by the poor solubility and self-aggregation of the photosensitizers, such as fullerenes, which limit their applicability. Here, we report a self-assembled Pd8 water-soluble molecular barrel MB that encapsulates and enables effective solubilization of fullerenes in water, overcoming these limitations to form a homogeneous supramolecular catalytic system in water. The host-guest complex (C70)2@MB exhibited a significantly enhanced photosensitization ability, effectively catalysing both the aerobic oxidative dehydrogenation of tetrahydroquinolines to quinolines and sulfide oxidation to sulfoxides with high selectivity. To our knowledge, this system represents the first C70-catalysed aerobic oxidative dehydrogenation of tetrahydroquinoline to the corresponding quinolines. Importantly, (C70)2@MB exhibits ∼12-fold improvement in photocurrent response relative to free C70, suggesting superior charge separation and transfer within the confined environment of MB. Furthermore, NMR titrations and computational studies revealed the MB's rectangular cavity co-binds substrates at the longer MB edges, alongside the encapsulated fullerenes. The combined effects of solubilization, aggregation prevention, enhanced charge separation, and substrate co-binding together contribute to the enhanced photosensitization ability of C70 upon encapsulation within MB in an aqueous solution. MB thus, functions as an enzyme-like molecular reactor harnessing fullerene photochemistry for light-driven transformations in water.

Herein, defect engineering strategies were applied to enhance the photocatalytic activity of squarate-based MOFs (IEF-11) for green hydrogen generation via water splitting. The textural properties of pristine IEF-11(Ti) were significantly improved using microwave (MW)-assisted synthesis, leading to a four-fold increase in surface area (350 m2 g-1) due to the formation of mesopores associated with defect aggregation, primarily arising from linker vacancies (24%). Vanadium doping (0-100%) progressively reduced the optical band gap (2.44-1.87 eV), shifting absorption toward the visible region. The IEF-11 series was evaluated as photocatalysts for the hydrogen evolution reaction under simulated sunlight irradiation, revealing a volcano-type trend correlating activity with V content. Doped with 11% V, the MW-synthesized IEF-11(Ti0.89V0.11)_MW solid exhibited the highest activity (1053 vs. 536 μmol g-1 h-1 H2 for IEF-11(Ti)), attributed to optimized band alignment, enhanced charge separation, and structural robustness. It also showed activity in photocatalytic overall water splitting (83 μmol g-1 h-1 H2, 30% higher than the undoped IEF-11(Ti)). Theoretical calculations further confirmed band gap narrowing and the generation of new electronic states upon V-doping, facilitating charge transfer and reducing electron-hole recombination. These findings highlight the relevance of inducing artificial porosity and V-doping of IEF-11(Ti) to prepare efficient MOF-based photocatalysts. Importantly, this work not only reports the first V-squarate frameworks but also represents one of the first systematic studies addressing the effect of metal doping in MOFs for photocatalytic water splitting, achieving competitive efficiencies operating in the absence of cocatalysts.

ABSTRACT Covalent organic frameworks (COFs) have been recognized as versatile platforms for photocatalytic CO 2 reduction reactions (CO 2 PRR), owing to their inherent merits of tunable photo‐responsiveness, structural flexibility, high porosity and molecular precision. However, the adsorption and activation of CO 2 within pristine COFs remain challenging due to the lack of strong binding and catalytic sites. To address this, extensive efforts have been dedicated to incorporating active metal centers into COFs, to enhance charge separation, CO 2 adsorption, and redox processes. Despite these advances, a comprehensive analysis correlating metal incorporated strategies with photocatalytic performance remains lacking. This review timely fills this gap by linking the structural and functional properties of metal‐embedded COF with CO 2 PRR activities. We first outline the structural features and design principles of COFs, then highlight representative metal incorporation approaches and the resulting structure–function relationships. Finally, perspectives are presented on the opportunities and challenges of advancing metal‐modified COFs for solar‐driven CO 2 conversion with high performance and on‐demand selectivity. This review will also offer critical insights into intelligent COFs design and inspire future developments in photocatalytic carbon dioxide capture and upgrading.

Among viable approaches to address the current energy crisis, photocatalytic water splitting to produce hydrogen (H2) stands out as a promising strategy for converting solar energy into storable chemical energy. In this study, FeCoNiCuPt high-entropy alloy particles (HEA) are loaded onto protonated g-C3N4 nanosheets (HCN NSs) to construct HEA/HCN composites through an electrostatic self-assembly method. Protonation treatment enriches the surface of g-C3N4 nanosheets with abundant active sites and enhances their interfacial charge separation capability. The optimal HEA/HCN composite exhibits a remarkable hydrogen evolution rate of 1672 µmol·h-1·g-1, representing a 98.35-fold enhancement compared to pristine HCN. The apparent quantum efficiency of HEA/HCN composite reaches 3.23% at λ = 370nm. Experimental characterizations reveal that the 2D ultrathin protonated g-C3N4 nanosheets possess a substantial specific surface area and shortened charge transfer distance, facilitating rapid migration of photoexcited electrons. The incorporation of HEA cocatalysts not only introduces additional active sites but also establishes Schottky junctions at the HEA/HCN interface. The synergistic effect effectively accelerates electron transport and suppresses the recombination of photogenerated carriers, thereby significantly enhancing the photocatalytic H2 production performance. This work provides new insights into the future application of high-entropy alloys as novel cocatalysts in photocatalysis.

Interfacial charge modulation in porphyrin-based COF/C3N5 S-scheme heterojunction for efficient metal-free peroxymonosulfate photoactivation.

Spectroscopic study of methylene blue hosted in bile salt self-assemblies.

Crystal-facet-dependent piezo-phototronic effect steering reaction pathway switching for efficient H2O2 production from pure water.

Beyond charge separation: Unraveling the synergy of piezoelectric polarization and structure engineering in carbon nitride for thermodynamically boosted H2O2 production

ABSTRACT To address key challenges in photocatalytic CO 2 reduction for syngas production—including low catalyst activity, difficult product ratio control, and poor photogenerated charge separation efficiency, a one‐step molten salt strategy was utilized to synthesize Cu + ‐doped In 2 S 3 , which achieves photocatalytic CO 2 reduction to syngas with yields of CO:H 2 ≈ 1:1. The introduced Cu + ions create sulfur vacancies, synergistically boosting CO 2 adsorption, charge separation, and light‐harvesting. Importantly, density functional theory (DFT) calculations confirm that Cu + doping effectively reduces the formation energy barrier of the key * CO intermediate, providing a thermodynamic driving force for the selective reduction of CO 2 to CO. This effectively promotes CO 2 adsorption and activation while thermodynamically lowering the energy barrier for the CO 2 reduction reaction. This study elucidates the synergistic enhancement mechanism between Cu + and sulfur vacancies and provides a feasible strategy for developing solar‐driven photocatalysts for CO 2 reduction.

Integrated machine learning and density functional theory to design C₃N₅ piezo-catalysts toward precise control of selective reactive oxygen species and efficient water purification.

Covalent interface engineering regulation of Sillen-Auivillius perovskite for boosting antibiotic photodegradation.

Interfacial engineering induced robust S-scheme heterojunction in Bi2Sn2O7/BiOBr for highly efficient sacrificial-agent-free CO2 photoreduction.