Conversion Of Chemical Energy Research Articles

Insight on photocatalytic synchronous oxidation and reduction for pollutant removal: Chemical energy conversion between macromolecular organic pollutants and heavy metal

Collaborative treatment of pollutants is a promising approach for wastewater treatment. In this work, a covalent organic framework material (COFs) with an imine structure was synthesised by the Schiff base reaction, and photochemical tests showed good photochemical effects. It was used to explore the photocatalytic treatment of co-existing pollutants (heavy metal ions and antibiotics) and the performance of treating co-existing wastewater was investigated. The degradation performance of levofloxacin (LVX) and Cr(VI) was improved in the coexisting pollutants system, with the LVX degradation being 4.2 times more effective than that of the LVX solitary system. Moreover, this phenomenon was also observed in LVX/Ag(I), LVX/Fe(III), sulfadiazine/Cr(VI), norfloxacin/Cr(VI) and tetracycline/Cr(VI) systems. The analysis of active species suggesting that the synergistic promotion of photocatalytic oxidation-reduction systems was not only promoting from the improvement of simple charge separation, but it was also found that high-valent metal species can act directly in the oxidative decomposition of antibiotics. The interaction of pollutants and intermediates were rationally exploited and confirmed by control experiments and theoretical calculation. This conclusion helps us to re-examine the underlying mechanisms of photocatalytic synchronous oxidation and reduction reactions, simultaneously beneficial for the development of mixed pollutant control processes.

Rational construction of noble-metal-free fuel cell-supercapacitor hybrid power source using polyaniline electrode as both anode and cathode

The integration of fuel cell device and supercapacitor device into a singular hybrid power source at the electrode level can make the best use of the advantages of each individual device and more importantly, eliminate the energy loss by virtue of the conversion of chemical energy to electric energy on electrocatalyst material and the storage of electric energy on energy storage material simultaneously. To avoid the use of noble metal electrocatalyst and exploit the dual electrocatalytic and capacitive function of polyaniline, a noble-metal-free fuel cell-supercapacitor hybrid power source employing polyaniline electrode as both anode and cathode is rationally constructed. Based on electrochemical in-situ Raman spectroscopy, this work proposes that the open circuit potential (OCP) of polyaniline electrode is a simple and quick indicator of the redox state of polyaniline. After carefully selecting the fuel and carbon-based support, it is found that the ascorbic acid fuel and the carbon fiber cloth supported polyaniline contributes to the lowest OCP threshold in the anode, and thus the fastest self-charge and largest stabilized open circuit voltage of hybrid power source. The hybrid power source can be self-charged to 0.32 V and yield a peak power density of 0.21 mW cm−2.

Advances and Challenges in Interfacial Binding Forces for Electrocatalysts.

As a practical chemical energy conversion technology, electrocatalysis could be used in fields of energy conversion and environmental protection. In recent years, significant research efforts have been devoted to the design and development of high-performance electrocatalysts because the rational design of catalysts is crucial for enhancing electrocatalytic performance. Creating electrocatalysts by forming interactions between different components at the interface is an important means of controlling and improving performance. Therefore, several common interfacial binding forces used for synthesizing electrocatalysts was systematically summarized in this review for the first time. The discussion revolves around the crucial roles these binding forces play in various electrocatalytic reaction processes. Various characterization techniques capable of proving the existence of these interfacial binding forces was also involved in the review. Finally, some prospects and challenges for designing and researching materials through the utilization of interfacial binding forces were presented.

Oriented structural design of MXene electrodes for lithium sulfur catalysis

The lithium-sulfur reaction can contribute to the chemical electrical energy conversion capacity due to the multi-level ion/electron transfer process. However, the appearance of soluble intermediate products prevents efficient electron transfer, making it impossible to achieve stable cycling and capacity contribution. Restricted catalysis provides a solution for inhibiting the shuttle of soluble lithium polysulfides. Herein, MXene aerogel with optimized channel utilization is designed as S host according to the polysulfide control strategy of localization, adsorption, and catalysis. With the help of the results of oriented channels, the polysulfide conversion process is optimized, providing a comprehensive scheme for inhibiting the shuttle effect. Lithium sulfur catalytic batteries have achieved high capacity and stable cycling. This system provides a comprehensive solution for lithium sulfur reaction catalysis and a new perspective for the functional application of MXene based lithium sulfur batteries.

Investigating the Corrosion Resistance of Different SiC Crystal Types: From Energy Sectors to Advanced Applications.

Silicon carbide, as a third-generation semiconductor material, plays a pivotal role in various advanced technological applications. Its exceptional stability under extreme conditions has garnered a significant amount of attention. These superior characteristics make silicon carbide an ideal candidate material for high-frequency, high-power electronic devices and applications in harsh environments. In particular, corrosion resistance in natural or artificially acidic and alkaline environments limits the practical application of many other materials. In fields such as chemical engineering, energy conversion, and environmental engineering, materials often face severe chemical erosion, necessitating materials with excellent chemical stability as foundational materials, carriers, or reaction media. Silicon carbide exhibits outstanding performance under these conditions, demonstrating significant resistance to corrosive substances such as hydrochloric acid, sulfuric acid, nitric acid, and alkaline substances such as potassium hydroxide and sodium hydroxide. Despite the well-known chemical stability of silicon carbide, the stability conditions of its different types (such as 3C-, 4H-, and 6H-SiC polycrystals) in acidic and alkaline environments, as well as the specific corrosion mechanisms and differences, warrant further investigation. This Review not only delves deeply into the detailed studies related to this topic but also highlights the current applications of different silicon carbide polycrystals in chemical reaction systems, energy conversion equipment, and recycling processes. Through a comprehensive analysis, this Review aims to bridge research gaps, offering a comparative analysis of the advantages and disadvantages between different polymorphs. It provides material scientists, engineers, and developers with a thorough understanding of silicon carbide's behavior in various chemical environments. This work will propel the research and development of silicon carbide materials under extreme conditions, especially in areas where chemical stability is crucial for device performance and durability. It lays a solid foundation for ultra-high-power, high-integration, high-reliability module architectures, supercomputing chips, and highly safe long-life batteries.

A H2O2 Self‐Charging Zinc Battery with Ultrafast Power Generation and Storage

AbstractSelf‐charging power systems are considered as promising alternatives for off‐grid energy devices to provide sustained electricity supply. However, the conventional self‐charging systems are severely restricted by the energy availability and time‐consuming charging process as well as insufficient capacity. Herein, we developed an ultrafast H2O2 self‐charging aqueous Zn/NaFeFe(CN)6 battery, which simultaneously integrates the H2O2 power generation and energy storage into a battery configuration. In such battery, the chemical energy conversion of H2O2 can generate electrical energy to self‐charge the battery to 1.7 V through the redox reaction between H2O2 and NaFeFe(CN)6 cathode. The thermodynamically and kinetically favorable redox reaction contributes to the ultrafast H2O2 self‐charging rate and the extremely short self‐charging time within 60 seconds. Moreover, the rapid H2O2 power generation can promptly compensate the energy consumption of battery to provide continuous electricity supply. Impressively, this self‐charging battery shows excellent scalability of device architecture and can be designed to a H2O2 single‐flow battery of 7.06 Ah to extend the long‐term energy supply. This work not only provides a route to design self‐charging batteries with fast charging rate and high capacity, but also pushes forward the development of self‐charging power systems for advanced large‐scale energy storage applications.

A H2O2 Self-Charging Zinc Battery with Ultrafast Power Generation and Storage.

Self-charging power systems are considered as promising alternatives for off-grid energy devices to provide sustained electricity supply. However, the conventional self-charging systems are severely restricted by the energy availability and time-consuming charging process as well as insufficient capacity. Herein, we developed an ultrafast H2O2 self-charging aqueous Zn/NaFeFe(CN)6 battery, which simultaneously integrates the H2O2 power generation and energy storage into a battery configuration. In such battery, the chemical energy conversion of H2O2 can generate electrical energy to self-charge the battery to 1.7 V through the redox reaction between H2O2 and NaFeFe(CN)6 cathode. The thermodynamically and kinetically favorable redox reaction contributes to the ultrafast H2O2 self-charging rate and the extremely short self-charging time within 60 seconds. Moreover, the rapid H2O2 power generation can promptly compensate the energy consumption of battery to provide continuous electricity supply. Impressively, this self-charging battery shows excellent scalability of device architecture and can be designed to a H2O2 single-flow battery of 7.06 Ah to extend the long-term energy supply. This work not only provides a route to design self-charging batteries with fast charging rate and high capacity, but also pushes forward the development of self-charging power systems for advanced large-scale energy storage applications.

Alternative proton exchange membrane based on a bicomponent anionic nanocellulose system

As integral parts of fuel cells, polymer electrolyte membranes (PEM) facilitate the conversion of hydrogen's chemical energy into electricity and water. Unfortunately, commercial PEMs are associated with high costs, limited durability, variable electrochemical performance and are based on perfluorinated polymers that persist in the environment. Nanocellulose-based PEMs have emerged as alternative options given their renewability, thermal and mechanical stability, low-cost, and hydrophilicity. These PEMs take advantage of the anionic nature of most nanocelluloses, as well as their facile modification with conductive functional groups, for instance, to endow ionic and electron conductivity. Herein, we incorporated for the first time two nanocellulose types, TEMPO-oxidized and sulfonated, to produce a fully bio-based PEM and studied their contribution separately and when mixed in a PEM matrix. Sulfonated nanocellulose-based PEMs are shown to perform similarly to commercial and bio-based membranes, demonstrating good thermal-oxidative stability (up to 190 °C), mechanical robustness (Young's modulus as high as 1.15 GPa and storage moduli >13 GPa), and high moisture-uptake capacity (ca. 6330 % after 48 h). The introduced nanocellulose membranes are shown as promising materials for proton-exchange material applications, as required in fuel cells.

Enhancing the Efficiency of Rotary Thermal Propulsion Systems

Transport electrification is essential for reducing CO2 emissions, and technologies such as hybrid and range-extended electric vehicles will play a crucial transitional role. Such vehicles employ an internal combustion engine for on-board chemical energy conversion. The Wankel rotary engine should be an excellent candidate for this purpose, offering a high power-to-weight ratio, simplicity, compactness, perfect balance, and low cost. Until recently, however, it has not been in production in the automotive market, due, in part, to relatively low combustion efficiency and high fuel consumption and unburnt hydrocarbon emissions, which can be traced to constraints on flame speed, an elongated combustion chamber, and relatively low compression ratios. This work used large eddy simulations to study the in-chamber flow in a peripherally ported 225cc Wankel rotary engine, providing insight into these limitations. Flow structures created during the intake phase play a key role in turbulence production but the presence of the pinch point inherent to Wankel engine combustion chambers inhibits flame propagation. Two efficiency-enhancement technologies are introduced as disruptive solutions: (i) pre-chamber jet ignition and (ii) a two-stage rotary engine. These concepts overcome the traditional efficiency limitations and show that the Wankel rotary engine design can be further enhanced for its role as a range extender in electrified vehicles.

F-actin architecture determines the conversion of chemical energy into mechanical work

Mechanical work serves as the foundation for dynamic cellular processes, ranging from cell division to migration. A fundamental driver of cellular mechanical work is the actin cytoskeleton, composed of filamentous actin (F-actin) and myosin motors, where force generation relies on adenosine triphosphate (ATP) hydrolysis. F-actin architectures, whether bundled by crosslinkers or branched via nucleators, have emerged as pivotal regulators of myosin II force generation. However, it remains unclear how distinct F-actin architectures impact the conversion of chemical energy to mechanical work. Here, we employ in vitro reconstitution of distinct F-actin architectures with purified components to investigate their influence on myosin ATP hydrolysis (consumption). We find that F-actin bundles composed of mixed polarity F-actin hinder network contraction compared to non-crosslinked network and dramatically decelerate ATP consumption rates. Conversely, linear-nucleated networks allow network contraction despite reducing ATP consumption rates. Surprisingly, branched-nucleated networks facilitate high ATP consumption without significant network contraction, suggesting that the branched network dissipates energy without performing work. This study establishes a link between F-actin architecture and myosin energy consumption, elucidating the energetic principles underlying F-actin structure formation and the performance of mechanical work.

Elucidating the development of cooperative anode-biofilm-structures

Microbial electrochemical systems are a highly versatile platform technology with a particular focus on the interplay of chemical and electrical energy conversion and offer immense potential for a sustainable bioeconomy. The industrial realization of this potential requires a critical focus on biofilm optimization if performance is to be controlled over a long period of time. Moreover, the aspect and influence of cooperativity has to be addressed as many applied anodic bioelectrochemical systems will most likely be operated with a diversity of interacting microbial species. Hence, the aim of this study was to analyze how interspecies dependence and cooperativity of a model community influence the development of anodic biofilms. To investigate biofilm activity in a spatially resolved manner, a microfluidic bioelectrochemical flow cell was developed that can be equipped with user-defined electrode materials and operates under laminar flow conditions. With this infrastructure, the development of single and co-culture biofilms of the two model organisms Shewanella oneidensis and Geobacter sulfurreducens on graphite electrodes was monitored by optical coherence tomography analysis. The interdependence in the co-culture biofilm was achieved by feeding the community with lactate, which is converted by S. oneidensis into acetate, which in turn serves as substrate for G. sulfurreducens. The results show that co-cultivation resulted in the formation of denser biofilms than in single culture. Moreover, we hypothesize that S. oneidensis in return utilizes the conductive biofilm matrix build by G. sulfurreducens for direct interspecies electron transfer (DIET) to the anode. FISH analysis revealed that the biofilms consisted of approximately two-thirds G. sulfurreducens cells, which most likely formed a conductive 3D network throughout the biofilm matrix, in which evenly distributed tubular S. oneidensis colonies were embedded without direct contact to the anode surface. Live/dead staining shows that the outermost biofilm contained almost exclusively dead cells (98 %), layers near the anode contained 45–56 % and the entire biofilm contained 82 % live cells. Our results exemplify how the architecture of the exoelectrogenic biofilm dynamically adapts to the respective process conditions.

Experimental study of diphenylmethane gasification with supercritical CO2

Supercritical carbon dioxide (SCCO2) gasification reaction is one of the current popular research fields with wide application prospects in green chemical synthesis, environmental protection and energy conversion. This work aimed to investigate the effects of different conditions on the gas–liquid-solid three-phase products during the reaction of SCCO2 gasification of diphenylmethane. As a result, the carbon gasification efficiency (CE) and the hydrogen gasification efficiency (HE) were 25.99 % and 21.97 % respectively at 700 ℃ for 40 min, in which the CO reached the maximum of 15.64 ± 0.16 mol/kg. As the temperature and residence time increased, the apparent morphology of solid products became more homogeneous. In addition, based on the theories of cleavage of free radicals, secondary cleavage of free radicals and binding of free radicals, three pathways for the generation of fluorene, biphenyl and m-terphenyl were postulated. The experimental results provide fundamental data and theoretical support for an in-depth understanding of the reactions mechanism under the SCCO2 atmosphere, which is of great significance for deepening our knowledge of supercritical carbon dioxide reduction reactions and promoting green chemical synthesis research.

Optimizing Porosity and Heteroatom Functionalities in Amorphous Carbon-Rich g-C3N4 for Dual-Mode Photocatalysis through Solar to Green Hydrogen and Chemical Energy Conversion

Optimizing Porosity and Heteroatom Functionalities in Amorphous Carbon-Rich g-C₃N₄ for Dual-Mode Photocatalysis through Solar to Green Hydrogen and Chemical Energy Conversion

Energy storage and catalytic behaviour of cmWave assisted BZT and flexible electrospun BZT fibers for energy harvesting applications

High-performance lead-free Barium Zirconium Titanate (BZT) based ceramics have emerged as a potential candidate for applications in energy storage, catalysis for electro chemical energy conversion and energy harvesting devices as presented in this work. In the present study hybrid microwave sintered BZT are studied for dielectric, ferroelectric and phase transition properties. BZT ceramic exhibits tetragonal structure as confirmed by the Retvield refinement studies. XPS studies confirms the elemental composition of BZT and presence of Zr. Polarization versus electric field hysteresis loops confirms the ferroelectric behaviour of BZT ceramic. Encouragingly, the BZT showed a moderate energy storage efficiency of 30.7 % and relatively good electro chemical energy conversion (HER). Excellent catalytic activity observed for BZT electrode in acid medium with low Tafel slope 77 mV dec-1. Furthermore, electrospun nanofibers made of PVDF-HFP and BZT are used to make flexible piezoelectric nano generators (PENGs). FTIR studies show that the 16 wt% BZT composite ink exhibits a higher electroactive beta phase. The optimized open-circuit voltage and short circuit current of the flexible PENG exhibits 7Vpp and 750 nA under an applied force of 3N. Thus, flexible and self-powered BZT PENGs are alternative source of energy due to its reliability, affordability and environmental-friendly nature.

An overview of agro-industrial wastewater treatment using microbial fuel cells: Recent advancements

Discharge of agro-industrial wastewater causes severe damage to the environment due to the various hazardous components it contains. Progressive circular agriculture and industry involve closed cycles and zero-waste principles; therefore, waste treatment for subsequent reuse is of great interest. The microbial fuel cell (MFC) is a promising sustainable technology capable of treating wastewater at low cost without greenhouse gas (GHG) emissions while simultaneously producing electricity. The principle behind MFCs is based on the conversion of chemical energy into electricity using electrochemically active bacteria (EAB) as a biocatalyst. This article presents an overview of the progress and recent advancements in MFCs as a pivotal technology for agro-industrial wastewater treatment with production of sustainable electricity, compared to conventional treatment processes. Furthermore, the fundamental aspects of the design, configuration, operation, and application of MFCs in wastewater treatment (i.e., removal of inorganic nutrients, nitrate, phosphate, sulfate, sulfide, ammonium, organics, dyes, carbohydrates, fatty acids, and petroleum) are comprehensively discussed. Despite the viability and potential of MFCs in treating agro-industrial wastewater and producing electricity, they face various limitations and significant challenges, which are highlighted in this review. Future opportunities and perspectives on MFC applications are also discussed. Further research is required to address MFC limitations, which could make them feasible and practicable for real-world applications. However, MFC technology is clearly an excellent option for simultaneous wastewater treatment and electricity production without the need for external energy sources.

Advanced electron paramagnetic resonance in chemical energy conversion: current status and future potential

EPR aids catalyst research in energy systems by enhancing understanding, optimizing synthesis, elucidating mechanisms, and improving stability.

Remark on the entropy production of adaptive run-and-tumble chemotaxis

Chemotactic active particles, such as bacteria and cells, exhibit an adaptive run-and-tumble motion, giving rise to complex emergent behaviors in response to external chemical fields. This motion is generated by the conversion of internal chemical energy into self-propulsion, allowing each agent to sustain a steady-state far from thermal equilibrium and perform works. The rate of entropy production serves as an indicates of how extensive these agents operate away from thermal equilibrium, providing a measure for estimating maximum obtainable power. Here we present the general framework for calculating the entropy production rate created by such population of agents from the first principle, using the minimal model of bacterial adaptive chemotaxis, as they execute the most basic collective action – the mass transport.

Surface-dominant micro/nanofluidics for efficient green energy conversion.

Green energy conversion in aqueous systems has attracted considerable interest owing to the sustainable clean energy demand resulting from population and economic growth and urbanization, as well as the significant potential energy from water resources and other regenerative sources coupled with fluids. In particular, molecular motion based on intrinsic micro/nanofluidic phenomena at the liquid-solid interface (LSI) is crucial for efficient and sustainable green energy conversion. The electrical double layer is the main factor affecting transport, interaction between molecules and surfaces, non-uniform ion distribution, synthesis, stimulated reactions, and motion by external renewable resources in both closed nanoconfinement and open surfaces. In this review, we summarize the state-of-the-art progress in physical and chemical reaction-based green energy conversion in LSI, including nanoscale fabrication, key mechanisms, applications, and limitations for practical implementation. The prospects for resolving critical challenges in this field and inspiring other promising research areas in the infancy stage (studying chemical and biological dynamics at the single-molecule level and nanofluidic neuromorphic computing) are also discussed.

Substrate effect on charging of electrified graphene/water interfaces.

Graphene, a transparent two-dimensional (2D) conductive electrode, has brought extensive new perspectives and prospects to electrochemical systems, such as chemical sensors, energy storage, and energy conversion devices. In many of these applications, graphene, supported on a substrate, is in contact with an aqueous solution. An increasing number of studies indicate that the substrate, rather than graphene, determines the organization of water in contact with graphene, i.e., the electric double layer (EDL) structure near the electrified graphene, and the wetting behavior of the graphene: the graphene sheet is transparent in terms of its supporting substrate. By applying surface-specific heterodyne-detected sum-frequency generation (HD-SFG) spectroscopy to the silicon dioxide (SiO2)-supported graphene electrode/aqueous electrolyte interface and comparing the data with those for the calcium fluoride (CaF2)-supported graphene [Y. Wang etal., Angew. Chem., Int. Ed., 2023, 62, e202216604], we discuss the impact of the different substrates on the charging of both the graphene and the substrate upon applying potentials. The SiO2-supported graphene shows pseudocapacitive behavior, consistent with the CaF2-supported graphene case, although the surface charges on SiO2 and CaF2 differ substantially. The SiO2 surface is already negatively charged at +0.57 V (vs. Pd/H2), and the negative surface charge is doubled when negative potentials are applied, in contrast with the CaF2 case, where the positive charge is reduced when negative potentials are applied. Interestingly, the charging of the graphene sheet is almost identical between the negatively charged SiO2 surface and positively charged CaF2 surface, demonstrating that the graphene charging is decoupled from the charging of the substrates.

An Efficient Bias‐Free Si Photocathode Coupled BiVO4‐Triethanolamine Photoelectrochemical Fuel Cell for Simultaneous Pollutant Treatment and Hydrogen Production

AbstractPhotoelectrochemical (PEC) fuel cells that enable organic pollutants degradation while generating H2 are regarded as a viable approach in addressing global energy and environmental issues. Herein, an efficient PEC fuel cell is constructed using oxygen vacancy‐rich BiVO4 (OV:BiVO4) as the photoanode and triethanolamine (TEOA) pollutant as the fuel. Under AM 1.5 G, this OV:BiVO4–TEOA PEC fuel cell shows an ultra‐high photo‐driven current density of 20.40 mA cm−2 at 1.23 V versus reversible hydrogen electrode, which is superior to most reported PEC fuel cells. The Faradic efficiency of H2 production is about 97.26%, and no CO2 is released in the anode chamber due to the strong CO2 adsorption by excess TEOA. Further integration of a Pt/C cocatalyst coated Si photocathode in the OV:BiVO4–TEOA PEC fuel cell can achieve bias‐free H2 production with a current density of 10.17 mA cm−2. The experimental and theoretical calculation results reveal the importance of the robust complexation between the OV:BiVO4 photoanode and TEOA, which ensures thorough conversion of chemical energy in TEOA and high activity of the PEC fuel cell. This work will guide the design of efficient PEC fuel cells for simultaneous pollutant treatment and H2 production.