Solar Energy Conversion Efficiency Research Articles

АНАЛІЗ ВПЛИВУ ТЕМПЕРАТУРИ ЗОВНІШНЬОЇ СЕРЕДИ НА РОБОТУ ФОТОЕЛЕКТРИЧНИХ СТАНЦІЙ

This work is devoted to the study of the mechanism of increasing the efficiency of solar photovoltaic generation by integrating the compressed air system. The main aspects of this mechanism, its advantages and influence on the improvement of the process of converting solar energy into electrical energy are considered. The relevance of this topic is due to the constant growth of electricity consumption and the need to create efficient and sustainable solar power plants. Solar photovoltaic generation is already a promising source of renewable energy today, but it has certain limitations, in particular, related to the increase in temperature of solar panels and uneven distribution of solar radiation. This paper examines the integration of a compressed air system with solar panels to increase the efficiency of solar PV generation. The use of compressed air allows you to lower the operating temperature of the panels, which leads to an increase in the efficiency of solar energy conversion. In addition, it helps to unify the lighting of the panels and improves the performance of all photovoltaic modules. An important aspect of the work is the analysis of the influence of the integrated compressed air system on the energy characteristics of solar panels. The study includes modeling and experimental determination of changes in efficiency, energy output, and stability of solar panels when using a compressed air system. The obtained results allow us to draw conclusions about the efficiency and practical implementation of an integrated system of compressed air for solar photovoltaic generation. The identified advantages of this approach make it possible to recommend it for use in modern solar power plants in order to increase efficiency and ensure stable operation.

Unveiling the high activity origin of NiFe catalysts decorated Ta3N5 photoanodes for oxygen evolution reaction

Bimetallic NiFe catalysts could effectively promote the photoelectrochemical (PEC) water splitting activities of Ta3N5 photoanodes, while exploring the intrinsic activity origin is crucial for constructing highly efficient solar-energy conversion systems. Herein, we demonstrate a simple impregnation strategy for rational deposition of NiFe catalysts nanolayers on Ta3N5 nanotube photoanodes, which achieved a superior photocurrent density of 11.2 mA cm−2 at 1.23 V versus the reversible hydrogen electrode (RHE) accompanied by a low onset potential (0.3 VRHE). More importantly, systematic studies reveal that the preferred deposition of Fe catalysts nanolayers on Ta3N5 photoanode surfaces could effectively promote the charge separation and hole transfer, while the subsequent formation of Ni catalysts nanolayers could provide the catalytic active-sites for water oxidation. Accordingly, their synergistic effects significantly improve the interfacial hole transfer and surface oxygen evolution kinetics, leading to an outstanding PEC water splitting activity. This work not only clarifies the intrinsic high-activity origins of NiFe/Ta3N5 photoanodes, but also provides new insights into the rational construction of highly efficient OER catalysts for PEC water splitting.

Strain-Induced SiP–PtS2 Heterostructure with Fast Carrier Transport for Boosted Photocatalytic Hydrogen Conversion

Earth-abundant silicon-, phosphorus-, and sulfur-related compounds are crucial for optoelectronic application. Specifically, experimentally proven monolayer SiP has attracted a great deal of attention in above listed field owing to its unique properties but is plagued with challenges such as photocorrosion and poor charge separation. Moreover, theoretical understanding on the relationship of the interface and photocatalytic activity in SiP-based chemicals is not well understood. In this work, hybrid functional first-principles calculations were used to explore the photocatalytic hydrogen evolution activity of SiP–PtS2 heterostructure. Further examination of phonon, ab initio molecular dynamics (AIMD), and elastic property simulations confirms its dynamical stability. Its computed band gap of 1.59 eV is suitable for maximizing solar energy conversion efficiency, with noticeable strong absorption coefficients of 105 cm–1 order across visible–ultraviolet domains, asymmetric decent carrier mobility (∼103 cm2 V–1 s–1), and low exciton binding energy (0.56 eV). Differences in charge density and Bader and Mulliken population analyses reveal that charge flows from the SiP to the PtS2 layers, performing the dual functions of segregating photoinduced charge carriers and increasing their lifetimes. The relative band alignment of the monolayers promotes a spatial separation of the charges. An important feature of this heterostructure is that the band edges cross the water redox potential at pH of 0 upon −2% of compressive biaxial straining, with ΔG for hydrogen evolution reaction (HER) barrier lower than −0.2 eV. The quadratic relationship between biaxial strain and atomic energy indicates that both the system and strains are elastic. Redox thermodynamic analysis predicts facile hydrogen production on the heterostructure. In particular, the calculated maximum solar power conversion efficiency (PCE) and solar-to-hydrogen (STH) efficiency can reach 22.9 and 23.8%, respectively.

PbTiO3 Based Single-Domain Ferroelectric Photocatalysts for Water Splitting

ConspectusSolar-driven photocatalytic water splitting paves a way to produce green hydrogen for building a sustainable clean energy system, particularly within the framework of the carbon-neutral initiative. However, to date, the solar-to-hydrogen (STH) conversion efficiency of particulate photocatalysts falls far short of the demand of over 10% for industrial applications. Single-domain ferroelectric semiconductor materials with amazing unidirectional spontaneous polarization penetrating the bulk are promising candidates as photocatalysts for water splitting. Their existing inherent internal field set up by polarization can cause both two oppositely charged surfaces (namely, polar surfaces) and spatial separation of photogenerated charge carriers between them upon light excitation. These unique properties provide sufficient new room for flexibly engineering of bulk and surface/interface structures to enhance photocatalytic water splitting.In this Account, we offer a systematic overview of the exploration of PbTiO3 based single-domain ferroelectric photocatalysts for efficient solar water splitting. In detail, the controlled growth, surface modification, heterostructures, and Z-scheme system of single-domain PbTiO3 ferroelectrics are discussed by considering polar surfaces, spatial separation of the photoexcited charges, selective distribution of defects, and selective adsorption of reactive species. We start with the controlled synthesis of single-domain ferroelectric PbTiO3 nanoplates to realize the opposite directional transport of photoexcited charges driven by the polarized internal electric field, which can be verified by the fact that photochemical reduction/oxidation deposits occur on opposite polar surfaces. Then, we move to the selective modification of the specific polar surface to promote the transfer of photoexcited charges by applying the spatial separation effect of photoexcited charges and defects related internal screening mechanism. Furthermore, asymmetric heterostructures and Z-scheme systems are rationally designed by selective adsorption of reactive species on charged surfaces to promote charge separation and suppress redox mediator side reactions, respectively. Although significant advances have been achieved, many efforts remain needed toward the industrial production target. Based on single-domain ferroelectric photocatalysts, we present the following perspectives on the utilization of a wide solar spectrum for improving solar energy conversion efficiency. First, proper dopants can be incorporated homogeneously in the bulk to reduce the bandgap without obviously weakening ferroelectricity. Second, the epitaxial growth of narrow bandgap semiconductors on the ferroelectrics is feasible to induce additional polarization in the region close to their interface. These two aspects are anticipated to enable strong visible light absorption and charge separation efficiency. Third but not least, the assembly of Z-scheme systems with two narrow bandgap ferroelectrics is desirable to mimic natural photosynthetic systems with quantum yield approaching one unit.

Influence of spacer and donor groups as tetraphenylethylene or triphenylamine in asymmetric zinc phthalocyanine dyes for dye-sensitized solar cells

Based on the available literature, the carboxylic acid is a suitable electron-withdrawing group for the development of push–pull type AB3 phthalocyanines that can be used in dye-sensitized solar cell (DSSC). This study aims to assess the impact of carboxylic acid groups on solar cell energy conversion efficiency. Two types of carboxylic acid groups were selected as electron-withdrawing groups for this purpose. These groups were attached to the phthalocyanine (Pc) core either directly or via conjugated linker groups. Two novel push–pull zinc phthalocyanine dyes (GT-52 and GGC-22) containing tetraphenylethylene (TPE) or triphenylamine (TPA) substituents as electron donor groups and carboxylic acid or phenoxy carboxylic acid as anchoring groups, respectively, have been synthesized to construct DSSCs. The optical, electrochemical, and photovoltaic properties of the effect of the spacer and electron donor groups in these phthalocyanines are evaluated. Both dyes exhibit good anti-aggregation ability owing to the presence of the bulky donor groups. On the other hand, the DSSC based on GGC-22 showed a significantly higher power conversion efficiency (PCE) of 2.15% than that of GT-52 (0.26%) under AM 1.5G solar conditions. The superior performance of GGC-22 is attributed to the introduction of a phenoxy spacer, which results in a longer distance between the donor groups and the TiO2 surface compared to GT-52 without any spacer. This allows for higher dye loading, resulting in higher JSC, VOC, and PCE for GGC-22. As a result, the presence of a longer anchoring group for the donor groups is an important synthetic strategy for efficient phthalocyanine-based DSSCs.

Bifunctional Hot Water Vapor Template-Mediated Synthesis of Nanostructured Polymeric Carbon Nitride for Efficient Hydrogen Evolution.

Regulating bulk polymeric carbon nitride (PCN) into nanostructured PCN has long been proven effective in enhancing its photocatalytic activity. However, simplifying the synthesis of nanostructured PCN remains a considerable challenge and has drawn widespread attention. This work reported the one-step green and sustainable synthesis of nanostructured PCN in the direct thermal polymerization of the guanidine thiocyanate precursor via the judicious introduction of hot water vapor's dual function as gas-bubble templates along with a green etching reagent. By optimizing the temperature of the water vapor and polymerization reaction time, the as-prepared nanostructured PCN exhibited a highly boosted visible-light-driven photocatalytic hydrogen evolution activity. The highest H2 evolution rate achieved was 4.81mmol∙g-1∙h-1, which is over four times larger than that of the bulk PCN (1.19 mmol∙g-1∙h-1) prepared only by thermal polymerization of the guanidine thiocyanate precursor without the assistance of bifunctional hot water vapor. The enhanced photocatalytic activity might be attributed to the enlarged BET specific surface area, increased active site quantity, and highly accelerated photo-excited charge-carrier transfer and separation. Moreover, the sustainability of this environmentally friendly hot water vapor dual-function mediated method was also shown to be versatile in preparing other nanostructured PCN photocatalysts derived from other precursors such as dicyandiamide and melamine. This work is expected to provide a novel pathway for exploring the rational design of nanostructured PCN for highly efficient solar energy conversion.

Reversible Stacking of 2D ZnIn2 S4 Atomic Layers for Enhanced Photocatalytic Hydrogen Evolution.

It is technically challenging to reversibly tune the layer number of 2D materials in the solution. Herein, a facile concentration modulation strategy isdemonstrated to reversibly tailor the aggregation state of 2D ZnIn2 S4 (ZIS) atomic layers, and they are implemented for effective photocatalytic hydrogen (H2 ) evolution. By adjusting the colloidal concentration of ZIS (ZIS-X, X = 0.09, 0.25, or 3.0mg mL-1 ), ZIS atomic layers exhibit the significant aggregation of (006) facet stacking in the solution, leading to the bandgap shift from 3.21 to 2.66eV. The colloidal stacked layers are further assembled into hollow microsphere after freeze-drying the solution into solid powders, which can be redispersed into colloidal solution with reversibility. The photocatalytic hydrogen evolution of ZIS-X colloids is evaluated, and the slightly aggregated ZIS-0.25 displays the enhanced photocatalytic H2 evolution rates (1.11µmol m-2 h-1 ). The charge-transfer/recombination dynamics are characterized by time-resolved photoluminescence (TRPL) spectroscopy, and ZIS-0.25 displays the longest lifetime (5.55 µs), consistent with the best photocatalytic performance. This work provides a facile, consecutive, and reversible strategy for regulating the photo-electrochemical properties of 2D ZIS, which is beneficial for efficient solar energy conversion.

Fabrication of ATP/PEG/MnO2NWs composite for solar steam generation with high conversion efficiency

Solar steam generation is widely used in seawater desalination because of its high efficiency and environmental protection. However, using low-cost materials to produce efficient solar evaporators is a severe challenge. In this study, a porous carbon material was prepared by combining Attapulgite (ATP), Polyethylene glycol (PEG) and Manganese dioxide nanowires (MnO2NWs) composite, through freeze-drying and high-temperature carbonization. The prepared CAPM aerogel shows a three-dimensional porous structure, which has high evaporation properties in pure water and simulated seawater. Under 1 sun simulated illumination, the pure water evaporation is 1.4574 kg m-2h−1 and the corresponding energy conversion efficiency is 85.94%. The prepared CAPM aerogel showed excellent durability and salt tolerance in 20%Nacl solution, indicating that the CAPM has excellent desalinization performance. In addition, CAPM aerogel has and exhibits super hydrophilic properties, which can transfer water molecules quickly. Due to the advantages of low cost, simple preparation method, and high solar energy conversion efficiency, the CAPM has excellent potential as a photothermal material for solar energy generation.

Copper Nitride: A Versatile Semiconductor with Great Potential for Next-Generation Photovoltaics

Copper nitride (Cu3N) has gained significant attention recently due to its potential in several scientific and technological applications. This study focuses on using Cu3N as a solar absorber in photovoltaic technology. Cu3N thin films were deposited on glass substrates and silicon wafers via radio-frequency magnetron sputtering at different nitrogen flow ratios with total pressures ranging from 1.0 to 5.0 Pa. The thin films’ structural, morphology, and chemical properties were determined using XRD, Raman, AFM, and SEM/EDS techniques. The results revealed that the Cu3N films exhibited a polycrystalline structure, with the preferred orientation varying from 100 to 111 depending on the working pressure employed. Raman spectroscopy confirmed the presence of Cu-N bonds in characteristic peaks observed in the 618–627 cm−1 range, while SEM and AFM images confirmed the presence of uniform and smooth surface morphologies. The optical properties of the films were investigated using UV-VIS-NIR spectroscopy and photothermal deflection spectroscopy (PDS). The obtained band gap, refractive index, and Urbach energy values demonstrated promising optical properties for Cu3N films, indicating their potential as solar absorbers in photovoltaic technology. This study highlights the favourable properties of Cu3N films deposited using the RF sputtering method, paving the way for their implementation in thin-film photovoltaic technologies. These findings contribute to the progress and optimisation of Cu3N-based materials for efficient solar energy conversion.

Skin B/N-doped anatase TiO2 {0 0 1} nanoflakes for visible-light photocatalytic water oxidation

The limited visible-light-responsive photoactivities of most doped wide-bandgap photocatalysts with widened absorption range have long been the obstacles for the efficient conversion of solar energy to chemical energy by photocatalysis. The weak transport ability of visible-light-induced low-energy charge carriers, and numerous recombination centers arising from the energy-band modifiers along the transport path are two major factors responsible for such a mismatch. A potential solution is to shorten the transport path of photo-induced charges in well-modulated light absorbers with low-dimensional structure and the spatially concentrated dopants underneath their surfaces. As a proof of concept, skin B/N-doped red anatase TiO2 {001} nanoflakes with the absorption edge up to 675 nm were synthesized in this study. Experimental results revealed that boron dopants in the TiO2 nanoflakes from the hydrolysis of nanosized TiB2 played a crucial role in controlling nitrogen doping in the surface layer of the nanoflakes. As visible light excitation occurs at the surface layer, the photons can be sufficiently absorbed by the formed energy levels at the surface layers, and the photogenerated charge carriers can effectively migrate to the surface, thus leading to efficient visible-light-responsive photocatalytic oxygen evolution activity from water oxidation.

Atomic Cobalt-Silver Dual-Metal Sites Confined on Carbon Nitride with Synergistic Ag Nanoparticles for Enhanced CO2 Photoreduction.

Photocatalytic reduction of CO2 to value-added solar fuels is of great significance to alleviate the severe environmental and energy crisis. Herein, we report the construction of a synergistic silver nanoparticle catalyst with adjacent atomic cobalt-silver dual-metal sites on P-doped carbon nitride (Co1Ag(1+n)-PCN) for photocatalytic CO2 reduction. The optimized photocatalyst achieves a high CO formation rate of 46.82 μmol gcat-1 with 70.1% selectivity in solid-liquid mode without sacrificial agents, which is 2.68 and 2.18-fold compared to that of exclusive silver single-atom (Ag1-CN) and cobalt-silver dual-metal site (Co1Ag1-PCN) photocatalysts, respectively. The closely integrated in situ experiments and density functional theory calculations unravel that the electronic metal-support interactions (EMSIs) of Ag nanoparticles with adjacent Ag-N2C2 and Co-N6-P single-atom sites promote the adsorption of CO2* and COOH* intermediates to form CO and CH4, as well as boost the enrichment and transfer of photoexcited electrons. Moreover, the atomically dispersed dual-metal Co-Ag SA sites serve as the fast-electron-transfer channel while Ag nanoparticles act as the electron acceptor to enrich and separate more photogenerated electrons. This work provides a general platform to delicately design high-performance synergistic catalysts for highly efficient solar energy conversion.

European roadmap for the En-ActivETICS advancement and potential of the PV/PCM unventilated wall system application

The main goal of the European building market transformation regards the reduction of CO2 emissions and energy demand in the built environment towards net zero carbon buildings. This drives research and building practice to search for economically justified solutions that contribute to achieving these objectives. The work presented in this paper is concerned with the technological and economic context. The original solution of photovoltaic integration with the external thermal insulation composite system named the En-ActivETICS was developed, tested and analysed. The energy potential of the En-ActivETICS across Europe, considering south oriented façade is from 88.3 to 195.8 kWh/(m2⋅a), with the efficiency of solar energy conversion of around 13–14%. The problem of system overheating was solved by applying PCM mortar beside the PV panel, which allowed to keep the PV temperature below 70 °C. The risk of moisture load (from driven rain or water vapour condensation) was avoided by diffusion channels pressed in the mortar. Furthermore, the economic analysis of system implementation in Europe is also promising. Considering the availability of solar energy and electricity prices around Europe the payback time of the En-ActivETICS varies between 12 and 44 years for analysed countries. According to the presented roadmap for the En-ActivETICS advancement a payback period of <10 years is possible with a maximum cost of the system <275 EUR/m2 and electricity price >0.25 EUR/kWh.

Carbon-Dots-Modified Hierarchical ZnIn2S4/Ni-Al LDH Heterojunction with Boosted Charge Transfer for Visible-Light-Driven Photocatalytic H2 Evolution.

The construction of a heterojunction structure is considered a significant route to promote solar-driven H2 production. Herein, a CDs/ZnIn2S4/Ni-Al LDHs (CDZNA) ternary heterojunction was elaborately constructed via the in situ growth of ZnIn2S4 on Ni-Al LDHs with the incorporation of carbon dots (CDs) cocatalyst, which was used as a highly efficient catalyst for the photocatalytic H2 generation. Characterizations indicated that 2D ZnIn2S4 nanosheet homogeneously dispersed on the surface of Ni-Al LDHs fabricated an intimate hierarchical architecture and provided a high BET surface area (135.12 m2 g-1). In addition, the unique embeddable-dispersed CDs as electron mediators possessed numerous active sites and promoted the charge separation on ZnIn2S4/Ni-Al LDHs (ZNA) binary catalyst. By coupling these two features, the CDZNA catalyst exhibited a considerable H2 production rate of 23.1 mmol g-1 h-1 under visible-light illumination, which was 16.4 and 1.4 times higher than those of ZnIn2S4 and ZNA, respectively. A proposed mechanism of photocatalytic H2 production over the CDZNA catalyst was also discussed. This work provides a promising strategy to achieve highly efficient solar energy conversion in a ternary photocatalytic system.

From the perspective of experimental practice: High-throughput computational screening in photocatalysis

Photocatalysis, a critical strategy for harvesting sunlight to address energy demand and environmental concerns, is underpinned by the discovery of high-performance photocatalysts, thereby how to design photocatalysts is now generating widespread interest in boosting the conversion efficiency of solar energy. In the past decade, computational technologies and theoretical simulations have led to a major leap in the development of high-throughput computational screening strategies for novel high-efficiency photocatalysts. In this viewpoint, we started with introducing the challenges of photocatalysis from the view of experimental practice, especially the inefficiency of the traditional “trial and error” method. Subsequently, a cross-sectional comparison between experimental and high-throughput computational screening for photocatalysis is presented and discussed in detail. On the basis of the current experimental progress in photocatalysis, we also exemplified the various challenges associated with high-throughput computational screening strategies. Finally, we offered a preferred high-throughput computational screening procedure for photocatalysts from an experimental practice perspective (model construction and screening, standardized experiments, assessment and revision), with the aim of a better correlation of high-throughput simulations and experimental practices, motivating to search for better descriptors.

Photothermal strategies for ice accretion prevention and ice removal

Solar energy-based renewable energy conversion and storage technologies offer a great promise of combating energy shortage and transitioning to a sustainable society. Efficient collection and transformation play decisive roles in optimizing the harvest of solar energy. Photothermal conversion has emerged as the most efficient solar energy conversion technology, particularly, photothermal coatings could convert light into heat and has triggered a surge of interest in ice removal related applications. Here, we present a comprehensive review of popular documented photothermal conversion materials and the mechanisms of photothermal conversion technologies. Additionally, we pay attention to efficient light-trapping structures for outperformed solar-driven photothermal materials. After that, we investigate the mechanisms of the deicing process. Finally, we discuss the progress of photothermal deicing systems and summarize future challenges in improving their performance. This review serves as a reasonable reference for the classification of photothermal materials and the construction of light-trapping structures, providing valuable insight into the design of photothermal materials for anti-icing applications.

ЕКОЛОГО-ЕНЕРГЕТИЧНЕ ОБҐРУНТУВАННЯ ПОТРЕБИ В СІЛЬСЬКОГОСПОДАРСЬКИХ ПЛОЩАХ ДЛЯ ЗАБЕЗПЕЧЕННЯ ПРОДОВОЛЬЧОЇ БЕЗПЕКИ УКРАЇНИ

The article examines the energy equivalent of the needs in cultivated areas to ensure food security of Ukraine. It was determined that integration into WFE-strategies of food policy requires a comprehensive assessment of the energy component of agricultural production relative to the area of arable land, which will include the productivity of the main crops in the aspect of converting solar energy into food calories. A methodology was created and the efficiency of converting solar energy into the commodity energy value of the products of the grocery basket was calculated: 0.15-0.8% for cereals and vegetables, 0.042-0.054% for meat, 0.015-0.035% for drinks and spices, 0.12 % for dairy products, 0.37-0.93% for eggs. The overall efficiency of human consumption of solar energy through the food chain is 0.22%. To meet these needs, 1,831.3 m2 is needed, which receives 545.8 MW of solar energy during the growing season. It was determined that the yield fluctuations of the main crops are sinusoidal and their use in modeling the need for sowing areas will in the future allow to develop a dynamic model of management of benefits and quotas to stimulate the coverage of a possible shortage of certain main products. Also estimated is the amount of energy that can be used without affecting the yield by renewable energy when using a mobile configuration of its placement (or, on the contrary, directed to artificial lighting of the crop under stationary systems). As a result, basic indicators were obtained, which can be relied upon when developing a food security strategy for cities, and it was also determined that a standard household plot of 0.25 hectares fully covers the needs of one person with a surplus.

Improving oxygen evolution efficiency in BiVO4 photoanodes through surface facet control with TiCl3 as a structure guide agent

Efficient conversion of solar energy into chemical fuels through photoelectrochemical (PEC) water oxidation replies on highly efficient photoanodes. The surface crystal facet of photoanode plays a critical role in determining the injection efficiency of photocarriers from photoanode to electrolyte. Thus, controlling the formation of surface crystal facets is believed to be an effective strategy for improving the energy conversion efficiency of photoelectrodes. However, it is still challenging to technically control the formation of surface crystal facets. Herein, we proposed to use TiCl3 as structure guide agent in hydrothermally synthesizing BiVO4 photoanodes. By adjusting the amount of structure-directing agent and the temperature of the precursor, we obtained a series of BiVO4 photoanodes with different amount ratios of {010} and {110} facets. It was found that a photocurrent density of 1.07 mA/cm2 could be obtained when the {010} facet was grown perpendicular to the substrate at 75% area ratio, which is much higher than the 0.20 mA/cm2 of the randomly oriented sample of the crystal. The incorporation of structure-directing agents reduces the surface energy of the corresponding crystalline surfaces, leading to an increase in charge separation capacity attributed to the different charge transfer distances in various crystal orientations. This work provides new proposals into the rational design of photoanode crystal surface structures for efficient PEC water oxidation, may have significant implications for the development of highly efficient photoanodes in the future.

Phase Change Materials Encapsulated in Coral-Inspired Organic–Inorganic Aerogels for Flame-Retardant and Thermal Energy Storage

Phase change materials (PCMs) are considered ideal candidates for improving the efficiency of solar energy utilization because of their outstanding heat storage capacity. However, the further application of PCMs is limited by the issues of inferior shape stability, high fire hazard, and low thermal conductivity. Enlightened by the porous structure of coral in nature, a coral-like organic–inorganic graphene-modified PVA aerogel (GP) was designed as a host for PEG, resulting in a PCMs (P-GP) which has superior flame retardancy, shape stability, and solar-responsive thermal storage capacity. The thermal conductivity of P-G2.0P2.0 was significantly up, reaching 0.7545 W/(m·K), about 1.6 times that of PEG. As expected, the obtained P-G2.0P2.0 nanocomposites showed an ultrahigh thermal storage density (141.8 J) and an excellent shape stability. Additionally, the peak heat release rate and total heat release of the P-G2.0P2.0 were decreased by 37.5% and 25%, respectively, compared to those of PEG, showing superior fire safety. Due to the inorganic graphene acted as an effective light captor and molecular heated under solar light, the P-GP nanocomposites reached 50 °C within 80 s, indicating an efficient solar energy conversion, which have great potentials in solar energy storage and waste heat recovery.

Microwave-assisted synthesis of edge-grafted carbon nitride by triazole rings for efficient photocatalytic hydrogen evolution

Copolymerization of conjugated nitrogen heterocycles within carbon nitride nowadays is proven to be a successful strategy to promote charge separation. Here, a novel edge-grafted carbon nitride nanosheets by triazole rings were synthesized from the copolymerization of dicyandiamide and 3-amino-1, 2, 4-triazole via microwave-assisted heating with improved yield. Based on the building of a feasible donor-acceptor (D-A) system by such edge grafting, the rapid charge transfer pathways were formed. Benefiting from the thin-layer structure of carbon nitride via microwave-assisted heating and abundant π electrons by intramolecular doping, the system showed enhanced visible light absorption from n-π∗ electrons transition, facile charge separation and transfer, and then an increased H2 evolution rate (637.58 μmol h−1 g−1), which is 17.43 times than the triazole modified sample from conventional thermal condensation method. This work enlightens an innovative pathway for the regulation of carbon nitride photocatalysts by conjugated nitrogen heterocycles for efficient solar energy conversion applications.

Ferric-ellagate complex: A promising multifunctional photocatalyst

The semiconductors have exhibited great potential in the field of photocatalytic energy production, environmental remediation and bactericidal. Nevertheless, those inorganic semiconductors are still restricted in commercial application due to the drawbacks of easy agglomeration and low solar energy conversion efficiency. Herein, ellagic acid (EA) based metal–organic complexes (MOCs) were synthesized through a facile stirring process at room temperature with Fe3+, Bi3+ and Ce3+ as the metal center. The EA-Fe photocatalyst exhibited superior photocatalytic activity toward Cr(VI) reduction, where Cr(VI) were completely removed within 20 min. Meanwhile, EA-Fe also displayed good photocatalytic degradation of organic contaminants and photocatalytic bactericidal performance. The photodegradation rates of TC and RhB by EA-Fe were 15 and 5 times that by bare EA, respectively. Moreover, EA-Fe was capable of effectively eliminating both E. coli and S. aureus bacteria. It was found that EA-Fe was capable of generating superoxide radicals, which could participate in the reduction of heavy metals, degradation of organic contaminants and inactivation of bacteria. A photocatalysis-self-Fenton system could be established by EA-Fe solely. This work would provide a new insight for designing multifunctional MOCs with high photocatalytic efficiency.