Energy Conversion Efficiency Research Articles

Spontaneous enhanced photocatalytic overall water splitting on AlO/WSi2N4 vdW heterojunction

Completely achieving spontaneous water splitting without sacrificing co-catalysts poses a significant challenge, as factors such as electrical, optical, and catalytic activity can limit the conversion efficiency of solar energy to hydrogen. Herein, we propose a type-II van der Waals heterostructure composed of vertically stacked AlO and WSi2N4, and systematically investigate its mechanism and potential for catalyzing water splitting. Photon-induced photocatalytic water splitting takes advantage of the staggered energy bands of the heterojunction, effectively promoting the separation of photogenerated carriers and thus enhancing catalytic efficiency. In neutral water environment, the band edge position of AlO/WSi2N4 aligns with the redox potential required for water decomposition. Thermodynamic analysis of the oxygen and hydrogen evolution reactions indicates that the external potential provided by photogenerated carriers is expected to trigger spontaneous water decomposition. Moreover, with its high electron mobility (4800.62 cm2/Vs) and a solar-to-hydrogen energy conversion efficiency of up to 19.98 %, the AlO/WSi2N4 heterojunction demonstrates substantial potential as a photoelectric catalyst. This research introduces a promising avenue for efficient photocatalytic production of clean energy.

Membraneless organelles assembled by AuNPs-enzyme integration in non-photosynthetic bacteria: Achieving high specificity and selectivity for solar hydrogen production

The emergence of semiartificial photosynthesis holds great promise for improving light energy capture and conversion efficiency. However, achieving high product specificity and selectivity in semiartificial photosynthetic systems remains a challenge. In this study, we employed genetic engineering techniques to construct a membraneless organelle in E. coli, serving as the photoreaction carrier. The self-assembly of photosensitizers and hydrogenase within the carrier has successfully established a semiartificial photosynthetic model characterized by high product specificity and selectivity. In this model system, electrons were directly transferred to hydrogenase upon AuNPs light excitation in membraneless organelle, eliminating the need for additional electron mediators and bypassing the use of intracellular NADH/NAD+ as a reducing agent to avoid byproduct formation. The semiartificial photosynthetic system demonstrated an 11782-fold and 40-fold increase in hydrogen production compared to bare AuNPs and the empty vector E. coli hybrid system, respectively. This membraneless organelle holds the potential to robustly support the specific synthesis of high-energy-density, value-added compounds through solar energy conversion.

Condition for metal fragmentation during Earth-forming collisions

The long-term evolution of the deep Earth depends on its initial temperature and composition. These were set by the large planetary collisions that formed the Earth. After each collision, the metallic core of the impactor fell into a molten silicate magma ocean. Previous investigations showed that, as it sank, the impactor core fragmented into drops. The overall fragmentation of the core controlled the efficiency of chemical transfers between the impactor metal and the magma ocean, and, as a consequence, the composition of the Earth's core and mantle. However, because previous studies lack an impact stage, it is unclear whether the projectile core fragmented during the impact at Earth's surface, or deeper in the magma ocean.To answer this question, we conduct laboratory experiments modeling the collision of differentiated and undifferentiated impactors. In a first series of experiments, we investigate the impact of an undifferentiated centimetric liquid volume, representing the impactor core, onto a lighter immiscible liquid, representing the magma ocean. Our experiments approach the dynamical regime of planetary collisions for which inertia is large compared to surface tension. Varying the velocity and size of the impactor, we determine the conditions under which the impactor fragments into drops. We find that fragmentation occurs when the Froude number, which measures the relative importance of inertia to gravity, is larger than 40, regardless of surface tension. This fragmentation results from the growth of a turbulent Rayleigh-Taylor instability at the interface between the impacting liquid and the target pool. In contrast, when Fr<10, the impactor remains coherent. In a second series of experiments, we use two-phase impactors to show that these results hold for impactors that are differentiated into a core and a mantle.Applied to planet formation, our results suggest that the core of impactors less than 330 km in radius impacting at the escape velocity onto an Earth-sized planet fully fragments into droplets during the impact process, whereas the core of a giant Mars-sized impactor remains coherent. We derive a model for the depth at which the impactor core fragments in the magma ocean as a function of the impactor size and velocity. This model predicts that impactors with a radius less than 800 km fully fragment before reaching the bottom of the magma ocean. For velocities higher than twice the escape speed, some degree of fragmentation is unavoidable for any impactor size.

Evaluating battery electric vehicle usage in the EU: A comparative study based on member state energy mixes

The transport sector is undergoing a major transformation, as battery electric vehicles (BEV) are gaining ground. Therefore, assessing the sustainability aspects of their use is crucial to obtaining a clear picture of the sector. This article aims to meet this requirement by using European Union (EU) data for the period 2011 to 2021 and focuses not only on EU-27 aggregates but also on each member state separately. For the evaluation, a well-to-wheel (WTW) method was used to calculate two parameters: energy-specific CO2 emissions (ε) and total efficiency of energy conversions, transmission, and battery (ηtotal). For these values, the annual electricity mixes of the countries were tracked in 5 + 1 categories (combined cycle gas turbine (CCGT), thermal power plant, biofuels, nuclear power plant (NPP), renewables, and imports). The calculated results were illustrated by sustainability matrices describing the former and current positions of the countries. The EU-27 aggregate achieved a 0.04 increase (from 0.37 to 0.41) in total efficiency and a 29 gCO2/MJmotion decrease (from 113 to 84 gCO2/MJmotion) during the period. This ε value for 2021 was around half the world average. However, very significant differences were identified between member states, which are also assessed in the article with special emphases on the five most populated EU countries (Germany, France, Italy, Spain, and Poland).

Transcriptomics combined with physiology reveals the effect of different light qualities on the development of Fritillaria cirrhosa in the Qinghai Tibet Plateau

Fritillaria cirrhosa, a high-altitude plant susceptible to environmental conditions, commonly grows beneath bushes and is categorized as shade-tolerant. The development and secondary metabolite synthesis of F. cirrhosa are significantly influenced by light quality. This study investigated the physiological responses and molecular mechanisms of F. cirrhosa to different light qualities using colored agricultural film treatments. The results demonstrated that the number of sprout tumbles in F. cirrhosa was significantly reduced by the different colored film treatments. The quality of the fruits exhibited a notable improvement under the blue film (BF) treatment compared to the other groups (P < 0.05). The guanosine content showed a substantial increase of 440.55% under the BF treatment relative to the white film (WF), and the uracil content significantly increased by 171.27% in BF and by 296.38% in the green film (GF). Leaf thickness was considerably higher under the GF treatment than under the other conditions. F. cirrhosa demonstrated enhanced photosynthesis when exposed to BF and GF (P < 0.05). The transcriptome results indicated 75 differentially expressed genes (DEGs) involved in photosynthesis-related pathways that regulated photosynthetic utilization efficiency by encoding photosynthetic antenna proteins (Lhca and Lhcb), photosynthetic electron transporters (PsbE, PsbP, and PetA), and carbon fixation enzymes (PPC, PPDK, and rbcL). Most these genes were upregulated in BF and GF, improving the light energy conversion efficiency, photosynthetic electron transport rate, and CO2 assimilation ability in F. cirrhosa. Notably, 44 DEGs involved in flavonoid metabolic pathways (PAL, HCT, 4CL, CHS, CHI, and ANS) showed higher expression levels in WF and yellow film (YF), differing in the regulation of the photosynthetic pathway. This suggested that F. cirrhosa can utilize nutrients produced by photosynthesis more efficiently under BF and GF, and does not require excessive amounts of flavonoids for maintaining cell homeostasis. These results offer valuable insights into the transcriptional changes and molecular processes occurring in F. cirrhosa in response to different light qualities and provide a basis for research on the mechanisms of photo regulation, cultivation, and ecological adaptation in F. cirrhosa.

Cascade utilization of full spectrum solar energy for achieving simultaneous hydrogen production and all-day thermoelectric conversion

Solar-driven photocatalytic water/seawater splitting holds great potential for green hydrogen production. However, the practical application is hindered by the relatively low conversion efficiency resulting from the inadequate utilization of solar spectrum with significant waste in the form of heat. Moreover, current equipment struggles to maintain all-day operation subjected to the lack of light during nighttime. Herein, a novel hybrid system integrating photothermal catalytic (PTC) reactor, thermoelectric generator (TEG), and phase change materials (PCM) was proposed and designed (named as PTC-TEG-PCM) to address these challenges and enable simultaneous overall seawater splitting and 24-hour power generation. The PTC system effectively maintains in an optimal temperature range to maximize photothermal-assisted photocatalytic hydrogen production. The TEG component recycles the low-grade waste heat for power generation, complementing the shortcoming of photocatalytic conversion and achieving cascade utilization of full-spectrum solar energy. Furthermore, exceptional thermal storage capability of PCM allow for the conversion of released heat into electricity during nighttime, contributing significantly to the overall power output and enabling PTC-TEG-PCM to operate for more than 12 h under the actual condition. Compared to traditional PTC system, the overall energy conversion efficiency of the PTC-TEG-PCM system can be increased by ∼500%, while maintaining the solar-to-hydrogen efficiency. The advancement of this novel system demonstrated that recycling waste heat from the PTC system and utilizing heat absorption/release capability of PCM for thermoelectric application are effective strategies to improve solar energy conversion. With flexible parameter designing, PTC-TEG-PCM can be applied in various scenarios, offering high efficiency, stability, and sustainability.

Electrical energy efficiency of dye sensitized solar cells by polymer electrolyte

This research aims to prepare by mixtures method with dope carbon black as a working electrode and the apply it to the dye sensitized solar cells (DSSCs). The thin film of titanium dioxide nanocrystalline semi - conductor with dope carbon black, the cells were coated on to transparent conducting oxide glass sheet by means of the doctor blade technique as a working electrode. But the polymer electrolyte were prepare by adding potassium iodide and iodine salts with a ratio of KI:I2 was 10:1, into a polymer electrolyte composed of poly-ethylene glycol, ethylene carbonate and poly(styrene–co–acrylonitrile). The polymer electrolyte mixtures became homogeneous and stirring at a temperature of 80 °C. Found that efficiency for the DSSCs by polymer electrolyte based on yielded an overall light to electrical energy conversion efficiency ( ) of the DSSCs was 5.5095%, An open-circuit voltage of 0.58 V, voltage at the point of maximum power output of 0.42 V, short-circuit current density of 11.11 mA.cm–2, current density at the point of maximum power output of 10.50 mA.cm–2 fill factor of 0.684 under an irradiation of 80 mW.cm–2. And the long-term stability test of the DSSCs with a polymer electrolyte is evidently superior to the DSSCs with liquid electrolyte based on the observation period lasting for 90 days. GRAPHICAL ABSTRACT HIGHLIGHTS prepare by mixtures method with dope carbon black as a working electrode The efficiency for the DSSCs by polymer electrolyte based on yielded an overall light to electrical energy conversion

Control-inspired design and power optimization of an active mechanical motion rectifier based power takeoff for wave energy converters

Ocean waves have high energy density and are persistent and predictable. Yet, converting wave energy to a useable form remains challenging. A significant hurdle is the oscillatory nature of waves resulting in the alternating loads, which necessitate the use of rectification at some stage of the energy conversion. This research effort presents a novel design of active mechanical motion rectifier (AMMR) for the power takeoff (PTO), which provides enhanced controllability and better power performance when compared to passive mechanical motion rectifiers (MMR). Inspired by transistors used in synchronous electrical rectifiers, the proposed design uses controllable electromagnetic clutches in the mechanical transmission to allow active engagement-disengagement control; thus, rectifying the oscillatory motion into a unidirectional rotation for high energy conversion efficiency and allowing the generator in unidirectional rotation to control the bidirectional wave capture structure for maximizing the power output. A semi-analytical computational approach is developed to efficiently evaluate the optimal power achieved using the proposed AMMR-based PTO and active control. It is found that the AMMR-based PTO design yields a higher optimal power than the previous passive MMR design across the wave spectrum. The influences of generator inertia and reactive power are discussed. The effects of control parameters on the power output and the optimal trajectories are analyzed. Wave tank tests with the AMMR prototype demonstrated the effectiveness of AMMR based PTO design and validated the numerical analysis.

Shaping the Future of the Neurotransmitter Sensor: Tailored CdS Nanostructures for State-of-the-Art Self-Powered Photoelectrochemical Devices.

Semiconductor-based photoelectrochemical (PEC) test protocols offer a viable solution for developing efficient individual health monitoring by converting light and chemical energy into electrical signals. However, slow reaction kinetics and electron-hole complexation at the interface limit their practical application. Here, we reported a triple-engineered CdS nanohierarchical structures (CdS NHs) modification scheme including morphology, defective states, and heterogeneous structure to achieve precise monitoring of the neurotransmitter dopamine (DA) in plasma and noninvasive body fluids. By precisely manipulating the Cd-S precursor, we achieved precise control over ternary CdS NHs and obtained well-defined layered self-assembled CdS NHs through a surface carbon treatment. The integration of defect states and the thin carbon layer effectively established carrier directional transfer pathways, thereby enhancing interface reaction sites and improving the conversion efficiency. The CdS NHs microelectrode fabricated demonstrated a remarkable negative response toward DA, thereby enabling the development of a miniature self-powered PEC device for precise quantification in human saliva. Additionally, the utilization of density functional theory calculations elucidated the structural characteristics of DA and the defect state of CdS, thus establishing crucial theoretical groundwork for optimizing the polymerization process of DA. The present study offers a potential engineering approach for developing high energy conversion efficiency PEC semiconductors as well as proposing a novel concept for designing sensitive testing strategies.

Account of doping photocatalyst for water splitting

In the field of photocatalytic water splitting, the strategy of doping photocatalysts has emerged as a significant and extensively studied approach. Doping can effectively facilitate the modification of both the microstructure and energy band structure of the photocatalyst, addressing key performance limitations such as light absorption, position of the conduction and valence band minima (CBM and VBM), photogenerated carrier separation, and surface chemical reactions. In recent years, we have reported several works about the doping of rare earth elements into bismuth-based composite oxides. These endeavors are aimed at enhancing the conduction band minimum and achieving overall water splitting under visible light. Based on these bismuth-based composite oxides, we studied the effects of doping on the microstructures of photocatalysts, including exposed surfaces, surface properties, and defects. Recently, we introduce an innovative asymmetric doping technique—Selected Local Gradient Doping, intricately placing doped ions within nanocapsules. This approach allows for the gradual, controlled, and localized release of doped ions to the primary photocatalyst. Therefore, this account is to review our related research in the field of doping for photocatalytic water splitting. The primary focus on doping bismuth-based composite oxides and Asymmetry doping would significantly make contribution to the exploration of novel materials for photocatalytic water splitting under visible light and the enhancement of energy conversion efficiency.

Optimal strategy of the asymmetric wave energy converter survival in extreme waves

Enhancing the survival performance of wave energy converters (WECs) in extreme wave conditions is crucial, and reducing wave loads is a key aspect of this. Placing the device underwater has been recognized as a beneficial strategy, yet the determination of the optimal submerged depth and the effects of varying wave conditions remain ambiguous. To address this, the study numerically analyzes the total forces in both horizontal and vertical directions, along with their harmonic components, across different wave configurations. A computational fluid dynamics method is employed to investigate a triangular-baffle bottom-shaped oscillating floater, which is known for its high energy conversion efficiency. The findings indicate that submerging the device to a depth equivalent to half the actual focused amplitude (1/2Ab) is the most effective strategy in the given sea state, offering superior wave force reduction vertically and robust performance horizontally. The analysis of harmonics reveals the significant contribution of high-order components to the total wave forces. Additionally, the study examines the impact of focused wave amplitudes and peak frequencies, showing that although force reductions are lessened in more extreme conditions, the optimal submerged depth of 1/2Ab still yields near 30% reduction in total vertical force and 22% in total horizontal force. This research provides theoretical insight that can guide the enhancement of WECs' survival capabilities in practical engineering applications.

Energy transfer and release during the fracture of UD fiber-reinforced thermoplastic composites

This study delves into the complex dynamics of energy transfer and release during the fracture of unidirectional (UD) fiber-reinforced thermoplastic composites. Conducted through meticulous experimental observations and rigorous energy analysis, the research presents groundbreaking conclusions on the fracture toughness and energy conversion efficiency of UD carbon fiber composites under various loading conditions. A prominent focus is on how these mechanical properties are intricately linked to the sample’s fiber orientation angles and the external conditions applied during testing.The work employed tapered double cantilever beam (TDCB) as the far-field boundary to investigate the energy changes, transfer, and conversion processes during the crack propagation of unidirectional fiber reinforced thermoplastics (UDFRTPs) structures. It was found that throughout the entire propagation process, blunt extension occurs first followed by inertial extension. This is because in the initial stage of crack propagation, the stored elastic energy in the structure is relatively small, making the crack tip prone to blunting. This continuous blunting impedes the release of internal strain energy in the structure, with blunt extension accounting for a very small proportion of the entire fracture process. When the internal strain energy in the structure continues to increase to a certain extent, the blunting of the crack tip cannot prevent the release of a large amount of elastic energy inside the structure. At the same time, the excess released strain energy converts into kinetic energy and continually impacts the blunted region at the crack tip. At this point, the propagation transitions into the inertial extension stage, which occupies a significant portion of the entire fracture process.

Maximizing the Energy Scavenging Capability of Droplet Triboelectric Nanogenerators through Surface Engineering

Recent advancements in energy harvesting have led to innovative methods for converting droplet motion into electricity, such as droplet triboelectric nanogenerators (D-TENGs). However, enhancing their power generation capacity and efficiency remains a challenge. We present a novel surface engineering approach that significantly boosts the electrical outputs of the D-TENGs. By grafting perfluorodecyltrimethoxysilane (PFDTMS) onto polydimethylsiloxane (PDMS) surfaces pre-treated with sandpaper, we achieve a dual effect: fluoridation and increased contact area between droplets and PDMS. This modification, when applied to a droplet-based TENG, yields a remarkable 10-20 fold increase in power metrics such as current, charge, and voltage as compared to untreated counterparts, resulting in an energy conversion efficiency of 17.1% under a 30 MΩ load. Our enhanced D-TENG efficiently harvested energy from falling tap water droplets, producing a current of ~2mA. Remarkably, a single droplet impact could illuminate 400 LED lights. Furthermore, when coupled with capacitors, the device powered a hygrometer and 3W light bulbs, demonstrating substantial potential for real-world applications. This breakthrough in surface engineering for energy harvesters represents a significant step forward in the efficient and powerful generation of electricity from droplet motions.

A process flow of an air separation unit with an energy storage function: Utilizing distillation potential to absorb energy storage air and its performance

The integration of liquid air energy storage (LAES) and air separation units (ASUs) can improve the operation economy of ASUs due to their matching at refrigeration temperature. A process flow of an ASU with energy storage utilizing the distillation potential of the ASU to absorb the released air due to storing energy (i.e., the energy storage air) is proposed. Its novelty is thus: the ASU can be used to absorb the energy storage air to maximize the air utilization and improve the energy efficiency of the integrated system. It can be simulated using Aspen Plus software. Based on the simulated data, an optimal process flow is determined by analyzing the effect of a reduction in discharge of energy storage air on the distillation conditions of the ASU, and its energy efficiency analysis and economic evaluation are conducted. When the discharge of energy storage air is reduced by 50 % during energy storage and the stored liquid air is directly recovered into the ASU during energy release, a proposed process flow with largest absorption for energy storage air could be obtained. Its product exergy efficiencies for energy storage and release are 37.80 % and 37.57 %, respectively. The overall exergy efficiency of the LAES and the electrical round-trip efficiency of the proposed system are both 67.48 %, the electricity cost saving ratio is 6.43 %, and the payback period of the LAES is 2.4 years. The investment in an air booster accounts for the largest proportion of the overall cost (being some 49.3 % of the total investment required for such a LAES system). After the proposed system is applied throughout the industry, carbon dioxide emissions can be decreased by 15.12–26.76 Mt/year on the grid side.

Pseudo-transient flow path optimization of a solar tower receiver operating with supercritical carbon dioxide

Aiming to further promote the decarbonization of energy production processes, this article simulates and optimizes the pseudo-transient behavior of a cylindrical solar receiver subjected to a spatially varying concentrated heat flux. The model employed, which accounts for its thermal–hydraulic behavior, uses supercritical carbon dioxide (s-CO2) as the heat transfer fluid and is based on a literature-validated hybrid formulation that axially discretizes the tube of the receiver and simultaneously solves the 2-D temperature distribution within the cross-section of each node. The operational conditions imposed on the receiver were determined such that it can produce 10 MW in a recompression Brayton cycle. Also, the receiver’s surface was exposed to a spatially variable concentrated solar boundary condition based on the direct normal irradiance (DNI) of a representative day for each month of the year, which was selected from the typical meteorological year (TMY) in Seville (Spain). The results showed that the combined thermal–hydraulic efficiency of the receiver increases with the number of panels and that the mass flow flowing through each symmetrical side of the receiver should not necessarily be identical for achieving maximal efficiency. More importantly, the results showed that by simply changing the location of the s-CO2 inlet and outlet ports, one can increase the efficiency of the receiver by about 3 % while considering the exact same concentrated solar irradiation.

Energy-Conversion Device Using a Quantum Engine with the Work Medium of Two-Atom Entanglement.

Although entanglement is considered as an essential resource for quantum information processing, whether entanglement helps for energy conversion or output in the quantum regime is still lack of experimental witness. Here, we report on an energy-conversion device operating as a quantum engine with the working medium acted by two entangled ions confined in a harmonic potential. The two ions are entangled by virtually coupling to one of the vibrational modes shared by the two ions, and the quantum engine couples to a quantum load, which is another shared vibrational mode. We explore the energy conversion efficiency of the quantum engine and investigate the useful energy (i.e., the maximum extractable work) stored in the quantum load by tuning the two ions in different degrees of entanglement as well as detecting the change of the phonons in the load. Our observation provides, for the first time, quantitative evidence that entanglement fuels the useful energy produced by the quantum engine, but not helpful for the energy conversion efficiency. We consider that our results may be useful to the study of quantum batteries for which one of the most indexes is the maximum extractable energy.

Interplay of intermolecular and intramolecular vibrations mediates ultrafast singlet fission

Singlet fission (SF) is an exciton multiplication process that splits a singlet exciton in organic semiconductors into two triplet excitons and thus, can overcome the Shockley–Queisser limit to improve the solar energy conversion efficiency in photovoltaics. In this paper, we construct a unified model for the ultrafast primary step of the SF process. To achieve this, we investigate the dynamics of vibrational modes and their interactions with the relevant electronic excited states in prototypical SF materials, pentacene (exothermic SF) and tetracene (endothermic SF) single crystals. Additionally, the functional role of the charge transfer (CT) state is also examined. Using the refined parameters obtained from the reported experimental results, we deduce that the intermolecular vibrations mediate the SF in pentacene with the assistance from strong vibronic couplings to intramolecular modes, which drives the SF process to occur within 100 fs. In this timescale, the CT state has a limiting role towards the SF process in pentacene. However, the CT state plays an important role in a relatively slower SF process in tetracene. Our results disentangle the role of underlying vibrational coherences and clarify the importance of the CT state in tetracene crystal. Hence, with our unified model, we can study the coherent dynamics of the SF process, which can principally be extended to other SF materials as well.

Design and Fabrication of an Acetylene Fuel Vehicle

Abstract: The transition towards sustainable transportation necessitates exploring alternative fuels with reduced environmental impacts. Acetylene has emerged as a promising candidate due to its clean combustion characteristics and high energy density. This abstract outline the design and fabrication process of an acetylene fuel vehicle, focusing on its feasibility and performance. The design phase involves meticulous material selection to ensure compatibility with acetylene's properties while prioritizing safety measures. Key components such as the fuel storage system, combustion chamber, and propulsion system are engineered to maximize energy conversion efficiency and minimize emissions. Safety protocols for acetylene handling and storage are integrated into the design to mitigate risks associated with its high reactivity. Fabrication incorporates advanced manufacturing techniques like additive manufacturing and precision machining to create a robust vehicle prototype. The integration of selected components is optimized to enhance structural integrity and overall performance. Rigorous testing procedures are conducted to validate the vehicle's functionality, including performance metrics, emissions analysis, and safety evaluations. The outcomes of this study provide valuable insights into the feasibility of acetylene as a sustainable transportation fuel. The design and fabrication processes contribute to ongoing research efforts aimed at reducing the carbon footprint of the transportation sector. The results also offer a pathway for future developments in alternative fuel technologies, driving towards a more environmentally friendly and energy-efficient transportation ecosystem.

Constructing Metal(II)‐Sulfate Site Catalysts toward Low Overpotential Carbon Dioxide Electroreduction to Fuel Chemicals

Precise regulation of the active site structure is an important means to enhance the activity and selectivity of catalysts in CO2 electroreduction. Here, we creatively introduce anionic groups, which can not only stabilize metal sites with strong coordination ability but also have rich interactions with protons at active sites to modify the electronic structure and proton transfer process of catalysts. This strategy helps to convert CO2 into fuel chemicals at low overpotentials. As a typical example, a composite catalyst, CuO/Cu‐NSO4/CN, with highly dispersed Cu(II)‐SO4 sites has been reported, in which CO2 electroreduction to formate occurs at a low overpotential with a high Faradaic efficiency (−0.5 V vs. RHE, FEHCOO−=87.4%). Pure HCOOH is produced with an energy conversion efficiency of 44.3% at a cell voltage of 2.8 V. Theoretical modeling demonstrates that sulfate promotes CO2 transformation into a carboxyl intermediate followed by HCOOH generation, whose mechanism is significantly different from that of the traditional process via a formate intermediate for HCOOH production.

Constructing Metal(II)-Sulfate Site Catalysts toward Low Overpotential Carbon Dioxide Electroreduction to Fuel Chemicals.

Precise regulation of the active site structure is an important means to enhance the activity and selectivity of catalysts in CO2 electroreduction. Here, we creatively introduce anionic groups, which can not only stabilize metal sites with strong coordination ability but also have rich interactions with protons at active sites to modify the electronic structure and proton transfer process of catalysts. This strategy helps to convert CO2 into fuel chemicals at low overpotentials. As a typical example, a composite catalyst, CuO/Cu-NSO4/CN, with highly dispersed Cu(II)-SO4 sites has been reported, in which CO2 electroreduction to formate occurs at a low overpotential with a high Faradaic efficiency (-0.5 V vs. RHE, FEHCOO-=87.4%). Pure HCOOH is produced with an energy conversion efficiency of 44.3% at a cell voltage of 2.8 V. Theoretical modeling demonstrates that sulfate promotes CO2 transformation into a carboxyl intermediate followed by HCOOH generation, whose mechanism is significantly different from that of the traditional process via a formate intermediate for HCOOH production.