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Elemental phosphorus in its various allotropes has received tremendous research attention recently due to its intriguing electronic and structural properties. Notably, the application of nanostructured materials to overcome the inherent flaws in bulk materials is promising. However, many challenges need to be addressed before its widespread implementation. Thus, a specific tenet to design novel and robust nanomaterials is a decisive factor in the desired outcome, and the most daunting task before realizing this is solving the Schrödinger equation. First principle density functional theory (DFT) calculations have emerged as an insightful and accurate design tool to investigate the structural, electronic, and possible synthesis scenarios of yet undiscovered materials at atomic levels. In this review, the basic principles and the importance of DFT are discussed, followed by a summary of recent advances in the first principle study of elemental phosphorus‐based nanomaterials. Elemental phosphorus‐based nanomaterials and their allotropes have attracted growing interest in the renewable energy community due to their modulable product selectivity. However, the understanding of the physical phenomena of allotropic modification is still lacking. Therefore, the aim is to motivate experimental researchers to conduct DFT studies and experiments to comprehend relevant engineered nanomaterials better. Finally, the challenges and potential future research directions for further theoretical and computational development of phosphorus‐based nanomaterials are outlined. [ABSTRACT FROM AUTHOR]

The coupling of photoredox reactions utilizing both photogenerated electrons and holes has garnered significant attention for producing high-energy-density fuels and value-added products at the same time. In this work, all-in-one porous ultrathin ZnIn2S4 nanosheets were developed via a facile one-pot solvothermal method by carefully tuning the concentration of trisodium citrate in the synthesis medium. With the appropriate amount of trisodium citrate, the morphology structure of ZnIn2S4 can be modulated into 4–6 nm ultrathin layered sheets with noticeable nanopores of 10–70 nm, which exposes more active sites for the redox activity. The resultant cocatalyst-free ZnIn2S4 system was successfully employed in the photocatalytic H2 evolution coupled with benzyl alcohol oxidation to produce H2 fuel and benzaldehyde in the absence of sacrificial agents. The porous ZnIn2S4 nanosheets with ameliorated light absorption and enhanced redox capability achieved an optimal hydrogen yield of 22.2 mmol g−1 under 4 h simulated sunlight irradiation (AM 1.5), double that of its pristine form, resulting in an apparent quantum efficiency (AQE) value of 5.41% at 380 nm and a solar-to-hydrogen (STH) value of 0.204%. Interestingly, a highly selective (96%) benzaldehyde production of 0.33 mmol h−1 was observed concurrently with simultaneous benzyl alcohol conversion. In situ electron paramagnetic resonance (EPR) reveals that the high-selectivity benzaldehyde formation is attributed to the carbon-centered (Cα) radical-induced pathway with the direct involvement of the photogenerated holes in the C–H bond activation. Overall, this study highlights the importance of the morphology–activity relationship, providing valuable insights for the development of superior all-in-one ultrathin photocatalysts toward ameliorated dual-redox photocatalytic reactions. [ABSTRACT FROM AUTHOR]

Engineering an efficient semiconductor to sustainably produce green hydrogen via solar-driven water splitting is one of the cutting-edge strategies for carbon-neutral energy ecosystem. Herein, a superhydrophilic green hollow ZnIn2S4 (gZIS) was fabricated to realize unassisted photocatalytic overall water splitting. The hollow hierarchical framework benefits exposure of intrinsically active facets and activates inert basal planes. The superhydrophilic nature of gZIS promotes intense surface water molecule interactions. The presence of vacancies within gZIS facilitates photon energy utilization and charge transfer. Systematic theoretical computations signify the defect-induced charge redistribution of gZIS enhancing water activation and reducing surface kinetic barriers. Ultimately, the gZIS could drive photocatalytic pure water splitting by retaining close-to-unity stability for a full daytime reaction with performance comparable to other complex sulfide-based materials. This work reports a self-activated, single-component cocatalyst-free gZIS with great exploration value, potentially providing a state-of-the-art design and innovative aperture for efficient solar-driven hydrogen production to achieve carbon-neutrality. A superhydrophilic green hollow ZnIn2S4 was fabricated to realize unassisted photocatalytic overall water splitting. This work could provide an innovative aperture for efficient solar-driven green hydrogen production to achieve carbon neutrality. [ABSTRACT FROM AUTHOR]

Sunlight‐driven CO2 conversion into value‐added fuels emerges as an avant‐garde strategy to mitigate the imminent energy scarcity and global warming. Nevertheless, sluggish charge kinetics and rapid carrier recombination are deemed as the foremost bottlenecks of efficient CO2 photoreduction. In this contribution, the aforementioned shortcomings are addressed by assembling a homo–hetero architecture comprising oxygen‐defective ultrathin BiVO4 (BiVO4–Ov) and red/black phosphorus (RP/BP) homojunction with a built‐in nanoscale dual Z‐scheme electronic configuration. The development of BiVO4–Ov@RP/BP confers two electron relaying channels, that is, one from the RP/BP homojunction and another from the BiVO4–Ov/RP heterojunction, which warrant the efficient separation of electron–hole pairs. Besides, the ultrathin 2D and oxygen vacant nature of BiVO4–Ov exposes more active sites and renders electron trapping for efficient utilization of photogenerated charges. Amalgamating the desirable properties, the meticulously developed dual Z‐scheme homo–heterojunction system on the basis of surface defect‐engineered ultrathin BiVO4–Ov nanosheets integrated with RP/BP offers a new avenue for the exploration, design, and fabrication of new generation photocatalysts with exceptional photocatalytic activities. In particular, the BiVO4–Ov@RP/BP system demonstrates a remarkably high CH4 yield of 14.52 μmol g−1 after 6 h of visible light illumination, which resembles a leading‐edge photocatalytic performance among the existing BiVO4‐ and P‐based semiconductors. [ABSTRACT FROM AUTHOR]

Photocatalytic conversion of carbon dioxide (CO2) into value‐added fuels is a vastly promising anthropogenic chemical carbon cycle to combat the greenhouse effect while meeting the ever‐increasing energy demand. Recently, lead‐based halide perovskites have demonstrated great potential in various applications including photochemical reduction of CO2. However, in view of lead toxicity, the exploration of a lead‐free alternative is crucial for long term application. Herein, a series of lead‐free mixed halide perovskites Cs3Sb2ClxBr9−x (0 ≤ x ≤ 9) is prepared via a facile antisolvent recrystallization technique, where the incorporation of a secondary halide enhances the charge transfer and separation while allowing precise tuning of bandgap between 2.59 and 2.90 eV. Theoretical calculations further reveal that the formation of mixed Cl/Br halides engenders favorable charge redistribution due to lower octahedral distortion, which in turn strengthens CO2 adsorption and activation. Under visible light illumination, the optimal dual halide perovskite, Cs3Sb2Cl4Br5 manifests substantial twofold and fourfold enhancements of CH4 yield over the single halide perovskite, Cs3Sb2Br9 and Cs3Sb2Cl9, respectively. In brief, this study provides a compelling demonstration of lead‐free mixed halide perovskites for photocatalytic CO2 reduction, and it is anticipated to drive further application of perovskite‐based photocatalysts toward a diverse range of artificial photoredox reactions. [ABSTRACT FROM AUTHOR]

The rational engineering of photocatalytic active sites on an atomic scale with regulated H adsorption energy and accelerated reaction kinetics has been pivotal to realize photocatalytic H2 evolution reactions (HERs) without sacrificial reagents. Although hydrogen evolution from pure water splitting is at the forefront of solar H2 research, photocatalytic seawater splitting is more in line with the notion of sustainable development owing to the limited resources of freshwater. Herein, we report for the first time an H adsorption kinetics-oriented design of two-dimensional (2D) hexagonal ZnIn2S4 (ZIS) atomic layers via heteroatom P doping (ZIS-P) for the modulation of intrinsic S active sites to achieve sacrificial agent-free photocatalytic HERs using both pure water and seawater. Atomic insights from density functional theory (DFT) calculations reveal that non-metal P dopants with different valence electrons and electronegativity than substituted S3 atoms in ZIS give rise to the formation of a new hybridized level with a moderately filled state near the valence band maximum (VBM) and impart redistribution of electron density within the coordination, hence triggering the activation of neighboring S2 atoms. Thus, ZIS-P with tailored S2 atomic sites and fine-tuned electronic structure endows a diminishment in H adsorption–desorption barriers and enables energetically favorable HERs. In particular, the optimal ZIS-P sample demonstrated visible light-driven photocatalytic water splitting without any sacrificial reagents, resulting in H2 evolution rates of 1.68 μmol h−1 (pure water) and 1.54 μmol h−1 (simulated seawater), respectively. This work presents an approach to engineer the inert active sites, thus alleviating the strength of H adsorption free energy and enhance the HER kinetics. [ABSTRACT FROM AUTHOR]

Effective photocatalytic polyethylene degradation by TiO2 is hindered by the sluggish kinetics of alkyl hydroperoxide decomposition. Introduction of oxygen vacancies onto TiO2 destabilizes the hydroperoxide O – O bond due to mid-gap states and the elevated Fermi level. Downshift of the d-band center by oxygen vacancies also enhanced adsorbate–surface interactions and lowered the activation energy barrier from Gibbs calculations. Experimental evidence additionally substantiated enhanced polyethylene degradation on TiO2−x compared to TiO2. [ABSTRACT FROM AUTHOR]

ZnIn2S4 (ZIS) is an efficient photocatalyst for solar hydrogen (H2) generation from water splitting owing to its suitable band gap, excellent photocatalytic behaviour and high stability. Nevertheless, modifications are still necessary to further enhance the photocatalytic performance of ZIS for practical applications. This has led to our interest in exploring phosphorus doping on ZIS for photocatalytic water splitting, which has not been studied till date. Herein, phosphorus-doped ZnIn2S4 (P-ZIS) was modelled via Density Functional Theory to investigate the effects of doping phosphorus on the structural and electronics properties of ZIS as well as its performance toward photocatalytic water splitting. This work revealed that the replacement of S3 atom by substitutional phosphorus gave rise to the most stable P-ZIS structure. In addition, P-ZIS was observed to experience a reduction in band gap energy, an upshift of valence band maximum (VBM), an increase in electron density near VBM and a reduction of H* adsorption–desorption barrier, all of which are essential for the enhancement of the hydrogen evolution reaction. In overall, detailed theoretical analysis carried out in this work could provide critical insights towards the development of P-ZIS-based photocatalysts for efficient H2 generation via solar water splitting. [ABSTRACT FROM AUTHOR]

Dye wastewater has raised a prevalent environmental concern due to its ability to prevent the penetration of sunlight through water, thereby causing a disruption to the aquatic ecosystem. Carbon quantum dots (CQDs) are particularly sought after for their highly tailorable photoelectrochemical and optical properties. Simultaneously, graphitic carbon nitride (g-C3N4) has gained widespread attention due to its suitable band gap energy as well as excellent chemical and thermal stabilities. Herein, a novel boron-doped CQD (BCQD)-hybridized g-C3N4 homojunction (CN) nanocomposite was fabricated via a facile hydrothermal route. The optimal photocatalyst sample, 1-BCQD/CN (with a 1:3 mass ratio of boron to CQD) accomplished a Rhodamine B (RhB, 10 mg/L) degradation efficiency of 96.8% within 4 h under an 18 W LED light irradiation. The kinetic rate constant of 1.39 × 10–2 min−1 achieved by the optimum sample was found to be 3.6- and 2.8-folds higher than that of pristine CN and un-doped CQD/CN, respectively. The surface morphology, crystalline structure, chemical composition and optical properties of photocatalyst samples were characterized via TEM, FESEM-EDX, XRD, FTIR, UV–Vis DRS and FL spectrometer. Based on the scavenging tests, it was revealed that the photogenerated holes (h+), superoxide anions (∙O2–) and hydroxyl radicals (∙OH) were the primary reactive species responsible for the photodegradation process. Overall, the highly efficient 1-BCQD/CN composite with excellent photocatalytic activity could provide a cost-effective and robust means to address the increasing concerns over global environmental pollution. [ABSTRACT FROM AUTHOR]

Surface defect engineering on the nanoscale has attracted extensive research attention lately; however, its role in modulating the properties and catalytic performance of a semiconducting material has not been comprehensively covered. Here, we systematically unraveled the effect of defect engineering towards textural, electronic and optical properties of graphitic carbon nitride (g-C3N4), as well as its photocatalytic mechanism of CO2 reduction using first-principle calculations by density functional theory through the introduction of various defect sites. Among the five unique atoms in g-C3N4, the vacancy site was found to be the most feasible at the two-coordinated nitrogen, N2. By initiating N2 point defects, an asymmetric electron density distribution was engendered around the vacancy region, which resulted in an evolution of semiconducting properties. We also discovered an improved charge separation efficiency and CO2 adsorption affinity in g-C3N4, which rendered a more thermodynamically feasible pathway for CO2 reduction to CO, CH3OH and CH4 fuels. This theoretical finding is hoped to shed light on the importance of the defect engineering strategy towards photocatalytic enhancement in g-C3N4. [ABSTRACT FROM AUTHOR]

Over the years, researchers have placed increasing focus on extending the application of photocatalytic hydrogen (H2) evolution to seawater. Herein, a photocatalytic system with a unique combination of P‐doped Zn0.5Cd0.5S (pZCS) and noble‐metal‐free CoP is first fabricated to evaluate the synergy between them. The resultant sample achieves a significantly boosted photocatalytic H2 evolution reaction (HER) with a rate of 5488.8 μmol g−1 h−1, which is an almost 50‐fold enhancement from its pristine ZCS counterpart. Impressively, the CoP–pZCS composite also demonstrates overall water splitting where no sacrificial reagent is used, with an H2 evolution rate of 154.6 μmol g−1 h−1. The sample is then tested for its HER activity in seawater, and 3956.0 μmol g−1 h−1 of H2 is acquired. The main factor that contributes to its high performance in seawater despite various distractions coming from the abundance of ions present is the synergistic relation between pZCS and CoP. The midgap state procured through the introduction of the P dopant has excellent electron–hole separating ability, and CoP further serves as an electron sink where the photogenerated electrons can rapidly assemble. Ultimately, the charge carrier recombination within the resultant composite is greatly hindered, thus a spectacular photocatalytic HER in seawater is enabled. [ABSTRACT FROM AUTHOR]