Sustainable Energy Technologies Research Articles

Integrating Sustainable Energy Technologies into District Cooling Systems: A Review of Modelling and Optimisation Approaches

With the rising cooling demand and prevalent energy crisis, District cooling (DC) is evolving as one of the sustainable energy solution worldwide. As per ‘EHP DHC Outlook, May 2023’, the sales in DC sector reached 3 TWh, covering more than 150 European cities. The centralised nature of the DC system offer benefits such as energy efficient operations, sector coupling, peak load management. Further, the feasibility of integrating renewable technologies (eg. solar energy), free cooling sources (eg. seawater heatpumps) and thermal energy storage (eg. ice slurry) is also explored. These developments make the futuristic DC system quite complex, as it involves multiple energy transformations. In this regard, utilising computation tools for decision-making has become increasingly relevant. However, choosing the appropriate approach among the existing ones in this evolving field is a curb some task for energy practitioners. The aim of the study is to review the modelling and optimisation approaches in the context of innovative DC systems. Data collection and analysis is based on desk-review of scientific literature published in the recent past. Firstly, various possibilities of integrating sustainable energy technologies for DC applications are explored. Then, relevant modelling and simulation approaches are studied, focussing on the similarities and limitations. Finally, different optimisation methods are examined in terms of parameters such as objective functions, control variables, solving techniques. The contribution of the study involve overview of different integration pathways, identifying the strength and weakness of modelling approaches and insights into suitability of optimisation techniques. It is expected that this study will be a reference material, while performing feasibility studies as well as developing digital-twins in DC context.

FeCo‐oxalate Organic Framework as an Efficient Electrocatalyst for Oxygen Evolution Reaction

Developing nonprecious metallic electrocatalysts for water splitting is of vital importance for sustainable environment and energy technologies. As for oxygen evolution reaction (OER), FeCo‐based bimetallic catalysts have been found to act as promising candidates owing to their high intrinsic activity. Herein, a novel FeCo‐oxalate organic framework was grown on nickel foam (FeCo‐OA@NF) under mild conditions. The optimized electrocatalyst shows good OER performance with a low overpotential of 275 mV at the current density of 100 mA cm−2 in alkaline environment, comparable to that of commercial Ru‐based catalyst. Moreover, the quantification of produced oxygen by both gas chromatography and drainage method demonstrates nearly 100% Faradaic efficiency. Except for the contribution of Fe and Co species for the excellent OER catalytic activity, in‐situ Raman spectroscopy reveals that the positive effect of oxalate coordination also makes a difference, which can possibly reduce electron transport resistance and provide more active sites. This work provides a promising approach for the preparation of alkaline oxygen evolution electrocatalysts with low‐cost and high performance.

Cyclo[16]carbon through the lens of density functional theory: Role of impurity decoration in hydrogen evolution reaction

The increasing global demand for sustainable energy sources has intensified the search for cost-effective catalysts in the hydrogen evolution reaction (HER). Single-atom catalysts (SACs) supported on suitable substrates have emerged as promising alternatives. In this study, we investigate the utilization of cyclo[16]carbon (C16 nanocluster) as a support for second-row transition metals (TMs) based SACs. The exploration focuses on analyzing the geometry, electronic properties, stability, and catalytic performance of TM@C16 SACs in the context of HER. Notably, highly negative binding energy values, structural modifications, and altered dipole moments collectively affirm the strong binding between the TMs and the C16 nanocluster. The incorporation of TMs onto the C16 nanocluster substantially enhances the conductivity of the latter. Studied SACs primarily showed H2 evolution via Volmer-Heyrovsky mechanisms. Notably, Pd@C16 and Rh@C16 displayed superior catalytic performance, with ΔGHV values of −0.007 eV and 0.05 eV, respectively. The determination of the exchange current via a volcano plot as a function of Gibbs free energy for hydrogen evolution over these designed SACs further validates their efficacy. Our findings establish Pd@C16 and Rh@C16 as highly stable and efficient SACs for the HER, underscoring their potential in advancing sustainable energy technologies.

Triboelectric power generation performance of polyvinyl alcohol using ZnO–CuO–AgO trimetallic nanoparticles

AbstractTriboelectric nanogenerators (TENGs), a new technology for gathering sustainable energy, have attracted much scientific interest. In this study, we describe a unique method for modifying the triboelectric power generation performance of Polyvinyl Alcohol (PVA) by adding ZnO–CuO–AgO (ZCA) trimetallic nanoparticles to improve the performance of TENGs and answer the requirement for ecologically benign and biodegradable materials. Hydrothermal synthesis adopted to create ZnO–CuO–AgO trimetallic nanoparticles ensures a distinctive structure with a large surface area, essential for enhancing triboelectric power generation. From the AFM results, it is evident that 1% PVA/ZCA showed the highest output voltage of 0.27V. Despite following the general trend, at higher concentrations of ZCA nanofiller in the PVA matrix, the enhancement of output voltage is not observed, which can be attributed to the non-uniform distribution. The effect of spin-coated film thickness and nanoparticle concentration on the triboelectric performance of the PVA nanogenerator is studied by monitoring the open-circuit voltage in response to various mechanical stimuli. Finally, the developed biodegradable nanogenerators in this study can be used for sustainable energy harvesting applications such as wearable electronics, self-powered sensors, and environmental monitoring systems.

Synergistic Optimization of Europium‐Doped Yttria for Photoluminescence and Triboelectric Nanogenerator Applications

In recent years, multifunctional applications of the same material have gained wide recognition in various fields. The present study reports the synthesis, characterization, and multifunctional applications of europium (Eu)‐doped yttrium oxide (Y2O3) nanophosphor. Synergistic optimization of Eu‐doped Y2O3 results in enhanced photoluminescence (PL) and triboelectric nanogenerator (TENG) performance. Eu‐doped Y2O3 nanophosphors are synthesized using an autocombustion method, and comprehensive characterizations are conducted. The investigations indicate that the Eu doping significantly influences the PL intensity, with the highest emission observed at 3 mol% for powders. The synthesized nanophosphors are blended with silicone to fabricate hybrid films, which are utilized for energy harvesting applications using TENG technology. The TENG devices fabricated with these hybrid films demonstrate a notable relationship between the Eu concentration and the electrical output, achieving peak performance at 1 mol% Eu doping. The maximum output voltage of ≈535 V, short‐circuit current of ≈38 μA, and power density of 800 mW m−2 are observed. Further, TENG is demonstrated in a self‐powered UV photodetector application. The present results contribute to the improvement of sustainable energy technologies and open up a new window for multifunctional materials.

Corrosion and Protection of Electrocatalysts toward Advanced Energy Technologies

AbstractHigh‐efficiency electrocatalysts play an important role in clean energy conversion technologies. Generally, electrocatalysts in different environments, including voltage, acid, and alkali electrolytes, are more susceptible to corrosion, which will induce structural and performance changes. Based on the latest achievements in the corrosion and protection of electrocatalysts in advanced energy technologies, this review mainly studies the application of various corrosion strategies to construct superior electrocatalysts, including chemical etching, metal corrosion transformation, and corrosion reconstruction, and their affecting factors are also appraised and summarized. To improve the stability of electrocatalysts, various corrosion inhibition strategies, such as carrier improvement and composition regulation accompanied by structure optimization, are reviewed. In addition, the application of catalyst corrosion in electrochemical energy technologies is examined from the perspective of the structure‐activity‐performance relationship. In the end, this article concludes the perspective and challenges of electrocatalyst corrosion in energy conversion and storage technologies. This article provides insights and directions for designing electrocatalysts with high efficiency and low corrosion, which is beneficial for developing corrosion chemistry for sustainable energy technologies.

Atomic Molybdenum Nanomaterials for Electrocatalysis.

As a sustainable energy technology, electrocatalytic energy conversion requires electrocatalysts, which greatly motivates the exploitation of high-performance electrocatalysts based on nonprecious metals. Molybdenum-based nanomaterials have demonstrated promise as electrocatalysts because of their unique physiochemical and electronic properties. Among them, atomic Mo catalysts, also called Mo-based single-atom catalysts (Mo-SACs), have the most accessible active sites and tunable microenvironments and are thrivingly explored in various electrochemical conversion reactions. A timely review of such rapidly developing topics is necessary to provide guidance for further exploration of optimized Mo-SACs toward electrochemical energy technologies. In this review, recent advances in the synthetic strategies for Mo-SACs are highlighted, focusing on the microenvironment engineering of Mo atoms. Then, the representative achievements of their applications in various electrocatalytic reactions involving the N2, H2O, and CO2 cycles are summarized by combining experimental and computational results. Finally, prospects for the future development of Mo-SACs in electrocatalysis are provided and the key challenges that require further investigation and optimization are highlighted.

Tuning Two-Dimensional Phthalocyanine Dual Site Metal-Organic Framework Catalysts for the Oxygen Reduction Reaction.

Metal-organic frameworks (MOFs) offer an interesting opportunity for catalysis, particularly for metal-nitrogen-carbon (M-N-C) motifs by providing an organized porous structural pattern and well-defined active sites for the oxygen reduction reaction (ORR), a key need for hydrogen fuel cells and related sustainable energy technologies. In this work, we leverage electrochemical testing with computational models to study the electronic and structural properties in the MOF systems and their relationship to ORR activity and stability based on dual transitional metal centers. The MOFs consist of two M1 metals with amine nodes coordinated to a single M2 metal with a phthalocyanine linker, where M1/M2 = Co, Ni, or Cu. Co-based metal centers, in particular Ni-Co, demonstrate the highest overall activity of all nine tested MOFs. Computationally, we identify the dominance of Co sites, relative higher importance of the M2 site, and the role of layer M1 interactions on the ORR activity. Selectivity measurements indicate that M1 sites of MOFs, particularly Co, exhibit the lowest (<4%), and Ni demonstrates the highest (>46%) two-electron selectivity, in good agreement with computational studies. Direct in situ stability characterization, measuring dissolved metal ions, and calculations, using an alkaline stability metric, confirm that Co is the most stable metal in the MOF, while Cu exhibits notable instability at the M1. Overall, this study reveals how atomistic coupling of electronic and structural properties affects the ORR performance of dual site MOF catalysts and opens new avenues for the tunable design and future development of these systems for practical electrochemical applications.

Bifunctional Strontium Cobalt Molybdenum Oxide (Sr2CoMoO6) Perovskite as an Efficient Catalyst for Electrochemical Water Splitting Reactions in Alkaline Media

Developing earth‐abundant low‐cost electrocatalysts is of prime research interest towards the need for clean energy technology, such as water‐splitting reactions. Herein, we have explored the electrocatalytic activity of the double perovskite‐based strontium cobalt molybdenum oxide (SCMO) towards water‐splitting reactions, both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Prepared by scalable autocombustion synthesis, the as‐synthesised bulk SCMO perovskite exhibited impressive electrocatalytic performance attributed to its substantial electrochemical active surface area. For the OER, it exhibited an overpotential of 350 mV with a Tafel slope value of 76 mV/dec. Concurrently, it showed proficient activity in the HER, revealing an overpotential of 270 mV and a Tafel slope of 112 mV/dec. Further, this perovskite material was stable during continuous electrocatalysis over a 24 h period with a negligible increase in observed overpotential value. The electronic density of states confirmed that the Co plays a pivotal role in enhancing electrocatalytic activities. This is achieved by a substantial reduction in the band gap and enhancement of the d‐band centre to an optimal level, rendering the system more favourable for electrocatalytic reactions. Our study contributes insights to the advancement of the design and utilization of perovskite‐based catalysts in the realm of sustainable energy technologies.

Biopolymer Materials in Triboelectric Nanogenerators: A Review.

In advancing the transition of the energy sector toward heightened sustainability and environmental friendliness, biopolymers have emerged as key elements in the construction of triboelectric nanogenerators (TENGs) due to their renewable sources and excellent biodegradability. The development of these TENG devices is of significant importance to the next generation of renewable and sustainable energy technologies based on carbon-neutral materials. This paper introduces the working principles, material sources, and wide-ranging applications of biopolymer-based triboelectric nanogenerators (BP-TENGs). It focuses on the various categories of biopolymers, ranging from natural sources to microbial and chemical synthesis, showcasing their significant potential in enhancing TENG performance and expanding their application scope, while emphasizing their notable advantages in biocompatibility and environmental sustainability. To gain deeper insights into future trends, we discuss the practical applications of BP-TENG in different fields, categorizing them into energy harvesting, healthcare, and environmental monitoring. Finally, the paper reveals the shortcomings, challenges, and possible solutions of BP-TENG, aiming to promote the advancement and application of biopolymer-based TENG technology. We hope this review will inspire the further development of BP-TENG towards more efficient energy conversion and broader applications.

Exploring the Influence of Cation and Halide Substitution in the Structure and Optical Properties of CH3NH3NiCl3 Perovskite.

This manuscript details a comprehensive investigation into the synthesis, structural characterization, thermal stability, and optical properties of nickel-containing hybrid perovskites, namely CH3NH3NiCl3, CsNiCl3, and CH3NH3NiBrCl2. The focal point of this study is to unravel the intricate crystal structures, thermal behaviors, and optical characteristics of these materials, thereby elucidating their potential application in energy conversion and storage technologies. X-ray powder diffraction measurements confirm that CH3NH3NiCl3 adopts a crystal structure within the Cmcm space group, while CsNiCl3 is organized in the P63/mmc space group, as reported previously. Such structural diversity underscores the complex nature of these perovskites and their potential for tailored applications. Thermal analysis further reveals the stability of CH3NH3NiCl3 and CH3NH3NiBrCl2, which begin to decompose at 260 °C and 295 °C, respectively. The optical absorption properties of these perovskites studied by UV-VIS-NIR spectroscopy revealed the bands characteristic of Ni2+ ions in an octahedral environment. Notably, these absorption bands exhibit subtle shifts upon bromide substitution, suggesting that optical properties can be finely tuned through halide modification. Such tunability is paramount for the design and development of materials with specific optical requirements. By offering a detailed examination of these properties, the study lays the groundwork for future advancements in material science, particularly in the development of innovative materials for sustainable energy technologies.

Special Issue: International Conference on Sustainable Energy Sources, Technologies and Systems 2023 (ICSESTS-2023)

Guest editorial introducing the special issue on the International Conference on Sustainable Energy Sources, Technologies and Systems 2023.

Advancing two-stage hydrogen production from corn stover via dark fermentation: Contributions of thermally modified maifanite to microbial proliferation and pH self-regulation

This study introduces a two-stage hydrogen production enhancement mechanism using natural particle additives, with a focus on the effects of thermally modified maifanite (TMM) and pH self-regulation on dark fermentation (DF). Initial single-factor experiments identified preliminary parameters for the addition of TMM, which were further optimized using a Box-Behnken design. The established optimal conditions which include mass of 5.5 g, particle size of 120 mesh, and temperature of 324 °C, resulted in a 28.7 % increase in cumulative hydrogen yield (CHY). During the primary hydrogen production stage, TMM significantly boosted the growth and activity of Clostridium_sensu_stricto_1, enhancing hydrogen output. Additionally, a pH self-regulating phenomenon was observed, capable of initiating secondary hydrogen production and further augmenting CHY. These findings presented a novel and efficient approach for optimizing biohydrogen production, offering significant implications for future research and application in sustainable energy technologies.

Design and optimization of a siphon turbine using the response surface methodology

A comprehensive examination of siphon turbine design and optimization using the response surface methodology (RSM) is presented in this study. The goal was to improve the turbine efficiency by analyzing the impact of two key factors: the number of blades (n) and the ratio between the hub diameter (d) and the outer diameter of the rotor (D), (d/D). The application of RSM facilitated the creation of a response surface, unveiling the optimal combination of factors for maximizing efficiency. The novelty of this article lies in utilizing the response surface methodology to refine the design of existing turbines, resulting in a more streamlined and effective design process tailored to the specific requirements of the installation. The findings indicated that rounding the number of blades to 5 and maintaining a constant d/D ratio of 0.35 yielded the highest efficiency (41.4%). Experimental validation was carried out and the accuracy of the optimized design was demonstrated, paving the way for practical applications in renewable energy solutions. Therefore, the effectiveness of RSM in optimizing siphon turbine designs is supported since valuable insights are provided for enhancing the energy efficiency in small-scale hydropower systems. The investigation contributes to the development of sustainable and clean energy technologies, showcasing the potential of siphon turbines in harnessing low-head water sources for power generation.

Multi-objective RSM-based optimization of diesel-diethyl ether blends in diesel engine to achieve sustainable development goals

With the plummeting reserves of fossil fuels at present, there has been a growing imperative for sustainable energy technologies over the last couple of decades. This imperative highlight the need for a shift towards renewable sources, not just to fulfill the current energy demands but also to lessen environmental degradation, fostering an eco-conscious and sustainable future. One way to accomplish such a goal is the utilization of diesel-diethyl ether (D-DEE) blends, instead of neat diesel in compression ignition (CI) engines. This study presents the multi-objective RSM-based analysis and optimization of D-DEE blends (0,5 and 10 %. vol) at manifold engine speeds (1200, 1400, and 1600 rpm). The responses that were recorded in this research included brake power (B.P), brake thermal efficiency (BTE), brake-specific fuel consumption, and CO2 emissions. The results demonstrated an increment in brake power as well as brake thermal efficiency, along with the enhanced CO2 emissions whereas the BSFC decreased while using the Di-ethyl ether enrichment in a 4-stroke CI engine. Upon implementing optimization parameters, the results illustrated the optimal blend ratio of 9.5786 %. vol at 1600 rpm, along with the associated values of B.P, BTE, BSFC, and CO2 emissions which were, 1.26726 kW, 20.861 %, 0.3354, and 7.837 % vol., respectively for this optimized fuel. This study addresses the lack of research on optimizing engine conditions for diesel-DEE blends in CI engines, specifically focusing on diethyl ether as a renewable fuel. Using response surface methodology (RSM), it aims to bridge this gap and contribute to the understanding of optimal blend utilization. The current research also aligns with the attainment of an important sustainable development goal (SDG) which includes the availability of responsible consumption (SDG 12) and improved power generation, contributing towards a greener and cleaner future.

Nano‐engineering in zinc‐based catalysts for CO2 electroreduction: Advances and challenges

AbstractElectrocatalytic CO2 reduction (CO2RR), an emerging sustainable energy technology to convert atmospheric CO2 into value‐added chemicals, has received extensive attention. However, the high thermodynamic stability of CO2 and the competitive hydrogen evolution reaction lead to poor catalytic performances, hardly meeting industrial application demands. Due to abundant reserves and favorable CO selectivity, zinc (Zn)‐based catalysts have been considered one of the most prospective catalysts for CO2‐to‐CO conversion. A series of advanced zinc‐based electrocatalysts, including Zn nanosheets, Zn single atoms, defective ZnO, and metallic Zn alloys, have been widely reported for CO2RR. Despite significant progress, a comprehensive and fundamental summary is still lacking. Herein, this review provides a thorough discussion of effective modulation strategies such as morphology design, doping, defect, heterointerface, alloying, facet, and single‐atom, emphasizing how these methods can influence the electronic structure and adsorption properties of intermediates, as well as the catalytic activity of Zn‐based materials. Moreover, the challenges and opportunities of Zn‐based catalysts for CO2RR are also discussed. This review is expected to promote the broader application of efficient Zn‐based catalysts in electrocatalytic CO2RR, thus contributing to a future of sustainable energy.

Solar Tracking Methods: A Comprehensive Survey

Abstract: In the pursuit of maximizing solar energy utilization, solar tracking systems have emerged as indispensable tools for enhancing the efficiency of photovoltaic (PV) systems. This comprehensive survey delves into the multifaceted landscape of solar tracking methods, elucidating the diverse techniques and strategies employed in optimizing solar panel orientation relative to the sun's position Solar tracking systems are classified into two primary categories: single-axis and dual-axis tracking. Single-axis tracking systems adjust solar panels along one axis, typically the azimuth axis, while dual-axis tracking systems dynamically alter both azimuth and elevation angles to accurately follow the sun's apparent motion across the sky.Within the realm of solar tracking, passive and active tracking methods are explored. Passive tracking mechanisms rely on natural phenomena such as gravity or thermal expansion to adjust panel orientation, whereas active tracking systems employ mechanical, electrical, or hydraulic actuators driven by motors or other means to actively adjust panel angles based on real-time tracking algorithms.A pivotal aspect of solar tracking systems is the selection and implementation of tracking algorithms. Various algorithms, including sun position algorithms, maximum power point tracking (MPPT) algorithms, and predictive algorithms, are analyzed for their effectiveness in accurately predicting and optimizing solar panel orientation.Furthermore, this survey scrutinizes the role of sensor technologies in solar tracking, encompassing GPS-based tracking, light-intensity-based tracking, weather-based tracking utilizing meteorological sensors, and horizon tracking techniques. These sensor-based methodologies offer different advantages and trade-offs in terms of accuracy, cost, and reliability. To provide a comprehensive understanding, comparative analyses are conducted, evaluating the efficiency, cost-effectiveness, and energy yield of different tracking methods. These comparative assessments offer valuable insights into the performance characteristics and suitability of various tracking methodologies across diverse applications and environmental conditions.In conclusion, this survey serves as an invaluable resource for researchers, engineers, and policymakers involved in the design, development, and optimization of solar tracking systems for renewable energy applications. By synthesizing the latest advancements and comparative analyses, this survey facilitates informed decision-making and fosters the advancement of sustainable solar energy technologies.

Photothermal performance of vitreous products from high-temperature melting of hazardous waste

High-temperature molten vitreous (HTMV), as the primary means of hazardous waste disposal, was produced in large quantities. Exploring its potential in photothermal applications could extend its high-value. Herein, the HTMV was used to explore the photothermal performance potential. It indicates that the HTMV possesses significant photothermal conversion capability, capable of increasing the tested water temperature by 6.65 °C. The HTMV mass and water volume are critical factors affecting the water temperature outcomes. The HTMV exhibits distinct conversion capabilities when applied at different application scenarios on the test object. Application on the bottom primarily focuses on photothermal conversion with high heat production efficiency, while side application additionally demonstrates excellent thermal insulation properties. Based on heat balance and backpropagation neural network predictions, optimal scheme of HTMV on both inside and outside bottom application scenarios of the heated object can achieve a maximum heat input of 660.6 kJ m−2 and 570.1 kJ m−2, respectively, and reduce carbon emissions by 0.062 kg CO2 m−2 and 0.054 kg CO2 m−2. This study not only provides a foundation for the further application of HTMV but also opens a new direction for the development of photothermal conversion materials, which is of great significance in advancing sustainable energy technology.

Excellent visible light absorption and ultra-high photoelectric conversion efficiency of two-dimensional (MoSe2)x(MoSTe)1-x mosaic heterostructures

Solar cells are a promising and potentially sustainable energy technology due to their cost-effectiveness, eco-friendliness, and capacity for integration into pliable apparatuses. Developing new photovoltaic materials to achieve higher photovoltaic conversion efficiency is a hot topic in the field of solar cells. In this work, the electronic structures and optical properties of two-dimensional (MoSe2)x(MoSTe)1-x mosaic heterostructures have been studied by density functional theory. Our results show that the mosaic heterostructures retain semiconductors with tunable band gap of 1.14–1.53 eV. With the augmentation of MoSe2 concentration in the mosaic heterostructures, the band gap of the materials has gradually increased. Besides, the mosaic heterostructures exhibit excellent optical absorption in the visible light region. Furthermore, the maximum theoretical photoelectric conversion efficiency of (MoSe2)0.80(MoSTe)0.20 mosaic heterostructure can reach 32.36 %. The tunable band gap, excellent light absorption, and ultra-high photoelectric conversion efficiency of (MoSe2)x(MoSTe)1-x mosaic heterostructures make them candidates for new nanocrystalline thin-film solar cells.

Sublayer-Sulfur-Vacancy-Induced Charge Redistribution of FeCuS Nanoflower Awakening Alkaline Hydrogen Evolution.

Advancing the progress of sustainable and green energy technologies requires the improvement of valid electrocatalysts for the hydrogen evolution reaction (HER). Reconfiguring charge distribution through heteroatom doping-induced vacancy serves as an effective approach to implement high performance for HER catalysts. Here, we successfully fabricated Fe-doped CuS (FeCuS) with the sublayer sulfur vacancy to judge its HER performance and dissect the activity origins. Density functional theory calculation further elucidates that the primary factor contributing to the heightened HER activity is that the sublayer sulfur vacancies awaken the charge redistribution. In addition to effectively decreasing the energy barrier associated with the Volmer step, it modulates the adsorption/desorption capacity of H*. As a result, its intrinsic activity for the HER has significantly increased. Concretely, the obtained FeCuS displays an excellent catalytic performance, whose Tafel slope is only 59 mV dec-1 and the overpotential (at 10 mA cm-2) is as low as 71 mV in an alkaline environment, surpassing the majority of previously documented catalysts in scientific literature. This work shows that the construction of sublayer sulfur vacancies by Fe doping can achieve the charge redistribution and precise tuning of electronic structure; thereby, the inert CuS can be transformed into highly efficient electrocatalysts.