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Solar saline water splitting is a promising approach to sustainable hydrogen production, harnessing abundant solar energy and the availability of brine resources, especially in the Atacama Desert. Bischofite salt (MgCl2·6H2O) has garnered significant attention due to its wide range of industrial applications. Efficient hydrogen production in arid or hyper arid locations using bischofite solutions is a novel and revolutionary idea. This work studied the electrochemical performance of Mn2O3 electrodes using a superposition model based on mixed potential theory and evaluated the superficial performance of this electrode in contact with a 0.5 M bischofite salt solution focusing on the hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR) that occur during saline water splitting. The application of the non-linear superposition model provides valuable electrochemical kinetic parameters that complement the understanding of Mn2O3, this being one of the novelties of this work. [ABSTRACT FROM AUTHOR]

In the last few years, the development of effective electrocatalysts hold fascinating importance towards scalable green hydrogen (H2) and oxygen (O2) production has become an appealing area of research. A good number of iron‐based catalysts have been designed and synthesized which can mediate water splitting under mild conditions with minimum energy requirements. In this review, recent progress on iron‐based electrocatalysts focusing on Oxygen Evolution Reaction (OER), Hydrogen Evolution Reaction (HER), and Overall Water Splitting (OWS) are summarized. Tactical designing, targeted synthesis with electronic tuning, efficiency as well as durability are discussed here. The review is comprehensive and our target is to promote the development of highly efficient economical catalysts, to make their way from the laboratory to market by replacing noble metal‐based electrocatalysts. [ABSTRACT FROM AUTHOR]

Facing with serious carbon emission issues, the production of green H2 from electrocatalytic hydrogen evolution reaction (HER) has received extensive research interest. Almost all kinds of noble metal phosphides (NMPs) consisting of Pt‐group elements (i.e., Ru, Rh, Pd, Os, Ir and Pt) are all highly active and pH‐universal electrocatalysts toward HER. In this review, the recent progress of NMP‐based HER electrocatalysts is summarized. It is further take typical examples for discussing important impact factors on the HER performance of NMPs, including crystalline phase, morphology, noble metal element and doping. Moreover, the synthesis and HER application of hybrid catalysts consisting of NMPs and other materials such as transition metal phosphides, oxides, sulfides and phosphates, carbon materials and noble metals is also reviewed. Reducing the use of noble metal is the key idea for NMP‐based hybrid electrocatalysts, while the expanded functionality and structure‐performance relationship are also noticed in this part. At last, the potential opportunities and challenges for this kind of highly active catalyst is discussed. [ABSTRACT FROM AUTHOR]

It is highly desirable to design efficient and stable hydrogen evolution reaction (HER) and oxygen evolution/reduction reaction (OER/ORR) electrocatalysts for the development of renewable energy technologies. Herein, density functional theory (DFT) calculations were conducted to systematically investigate a series of TMNxO4−x-HTT (TM = Fe, Co, Ni, Ru, Rh, Pd, Ir and Pt; HTT = hexahydroxy tetraazanaphthotetraphene) analogs of two-dimensional (2D) conductive metal-organic frameworks (MOFs) as potential electrocatalysts for the HER, OER and ORR. The thermodynamic and electrochemical stability simulations suggest that these designed catalysts are stable. Remarkably, CoO4-HTT, RhN3O1-HTT and IrN3O1-HTT are predicted to be the most promising catalysts for the HER, OER and ORR, respectively, surpassing the catalytic activity of corresponding benchmark catalysts. The volcano plots were established based on the scaling relationship of adsorption Gibbs free energy of intermediates. The results reveal that regulating combinations of metal active centers and local coordination environments could effectively balance the interaction strength between intermediates and catalysts, thus achieving optimal catalytic activity. Our findings not only opt for the promising HER/OER/ORR electrocatalysts but also guide the design of efficient electrocatalysts based on 2D MOFs materials. [ABSTRACT FROM AUTHOR]

The advancement of a sustainable and scalable catalyst for hydrogen production is crucial for the future of the hydrogen economy. Electrochemical water splitting stands out as a promising pathway for sustainable hydrogen production. However, the development of Pt‐free electrocatalysts that match the energy efficiency of Pt while remaining economical poses a significant challenge. This review addresses this challenge by highlighting latest breakthroughs in Pt‐free catalysts for the hydrogen evolution reaction (HER). Specifically, we delve into the catalytic performance of various transition metal phosphides, metal carbides, metal sulphides, and metal nitrides toward HER. Our discussion emphasizes strategies for enhancing catalytic performance and explores the relationship between structural composition and the performance of different electrocatalysts. Through this comprehensive review, we aim to provide insights into the ongoing efforts to overcome barriers to scalable hydrogen production and pave the way for a sustainable hydrogen economy. [ABSTRACT FROM AUTHOR]

Modern civilization has been highly suffering from energy crisis and environmental pollutions. These two burning issues are directly and indirectly created from fossil fuel consumption and uncontrolled industrialization. The above critical issue can be solved through the proper utilization of green energy sources where no greenhouse gases will be generated upon burning of such materials. Hydrogen is the most eligible candidate for this purpose. Among various methods of hydrogen generation, electrocatalytic process is one of the most efficient methods because of easy handling and high efficiency. In these aspects Co‐based nanomaterials are considered to be extremely significant as they can be utilized as efficient, recyclable and ideal catalytic system. In this article a series of Co‐based nano‐electrocatalysts has been discussed with proper structure‐property relationship and their medium dependency. Therefore, such type of stimulating summary on recently reported electrocatalysts and their activity may be helpful for scientists of the corresponding field as well as for broader research communities. This can be inspiration for materials researchers to fabricate active catalysts for the production of hydrogen gas in room temperature. [ABSTRACT FROM AUTHOR]

The quest for sustainable and clean energy sources has intensified research on the Hydrogen Evolution Reaction (HER) in recent decades. In this study, we have presented a novel Ce‐doped TiO2 catalyst synthesized through the sol‐gel method, showcasing its potential as a superior electrocatalyst for HER in an acidic medium. Comprehensive characterization through X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), Energy dispersive X‐ray (EDX), and Raman spectroscopy confirms the successful formation of the catalyst. Electrocatalytic performance evaluation, including open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), and Tafel analysis, demonstrates that GCE‐5wt.%CeTiO2 outperforms bare GCE, as well as Ce and TiO2‐based electrodes. Kinetic investigations reveal a Tafel slope of 105 mV dec−1, indicating the Volmer step as the rate‐determining step. The onset potential for HER at GCE‐5wt.%CeTiO2 is −0.16 V vs. RHE, close to the platinum electrode. Notably, the catalyst exhibits a low overpotential of 401 mV to achieve a current density of 10 mA cm−2 with an impressive 95 % Faradaic efficiency. Furthermore, the catalyst demonstrates outstanding durability, maintaining a negligible increase in overpotential during a 14‐hour chronoamperometry test. These results have far‐reaching implications for the development of cost‐effective and efficient electrocatalysts for hydrogen production. [ABSTRACT FROM AUTHOR]

Boron subphthalocyanines with chloride and fluoride axial ligands and three antimony complexes chelated by corroles that differ in size and electron‐richness were examined as electrocatalysts for reduction of protons to hydrogen. Experiment‐ and computation‐based investigations revealed that all redox events are ligand‐centered and that the meso‐C of the corroles and the peripheral N atoms of the subphthalocyanines are the largely preferred proton‐binding sites. [ABSTRACT FROM AUTHOR]

Precise design and synthesis of sub-nano scale catalysts with controllable electronic and geometric structures are pivotal for enhancing the hydrogen evolution reaction (HER) performance of molybdenum sulfide (MoS2) and unraveling its structure-activity relationship. By leveraging transition molybdenum polysulfide clusters as functional units for multi-level ordering, we successfully designed and synthesized MoSx nanowire networks derived from [Mo3S13]2− clusters via evaporation-induced self-assembly, which exhibit enhanced HER activity attributed to a high density of active sites and dynamic evolution behavior under cathodic potentials. MoSx nanowire networks electrode yields a current density of 100 mA·cm−2 at 142 mV in 0.5 M H2SO4. This work provides an attractive prospect for optimizing catalysts at the sub-nano scale and offers insights into a strategy for designing catalysts in various gas evolution reactions. [ABSTRACT FROM AUTHOR]

In the present work, the highly effective nanoscale Cu-modified dark TiO2 photocatalysts for hydrogen evolution reactions are prepared by pulsed laser ablation with and without additional laser treatment (ALT). Transmission electron microscopy HR results show that copper is distributed along the dark titania surface both in the form of subnanometer oxide clusters and single atoms (SAs). After the ALT, the Cu dispersion increases, and a large number of SAs appear. The X-ray photoelectron spectroscopy data indicate that the increasing copper content as well as the ALT lead to an increase in the surface Ti3+ content. Copper on the surface exists in the Cu+ state, which is associated with the strong metal-support interaction (SMSI) effect between the defective TiO2 support and a SA/subnanometer cluster of copper. Photocatalytic activity of nanoscale Cu-modified dark TiO2 is studied in the hydrogen evolution from aqueous glycerol solution under irradiation with light-emitting diodes (LEDs) 375 (soft ultraviolet) and LED 410 (visible region). In all cases, the modification of the surface with copper significantly increases the hydrogen yield in both the UV and visible regions. The ALT also leads to an increase in the photocatalytic activity of materials due to an increase in the SMSI between copper species and the surface of the dark TiO2. For the process of photocatalytic hydrogen evolution, a mechanism is proposed, and the products of glycerol photooxidation are identified. [ABSTRACT FROM AUTHOR]

Modifying the electronic structure of a catalyst through interface engineering is an effective strategy to enhance its activity in the hydrogen evolution reaction (HER). Interface engineering is a viable strategy to enhance the catalytic activity of transition metal phosphides (TMPs) in the HER process. The interface-engineered FeP/NiP2/Ni5P4/NiP multi-metallic phosphide nanoparticles confined in a N, P-doped carbon matrix was developed by a simple one-step low-temperature phosphorization treatment, which only requires 72 and 155 mV to receive the current density of 10 mA/cm2 in acid and alkaline electrolyte, respectively. This enhanced performance can be primarily attributed to the heterointerface of FeP/NiP2/Ni5P4/NiP multi-metallic phosphides, which promotes electron redistribution and optimizes the adsorption/desorption strength of H* on the active sites. Furthermore, the N, P-doped carbon framework that encapsulates the nanoparticles inhibits their aggregation, leading to an increased availability of active sites throughout the reaction. The results of this study open up a straightforward and innovative approach to developing high-performance catalysts for hydrogen production. [ABSTRACT FROM AUTHOR]

The exfoliation of bulk 2H-molybdenum disulfide (2H-MoS2) into few-layer nanosheets with 1T-phase and controlled layers represents a daunting challenge towards the device applications of MoS2. Conventional ion intercalation assisted exfoliation needs the use of hazardous n-butyllithium and/or elaborate control of the intercalation potential to avoid the decomposition of the MoS2. This work reports a facile strategy by intercalating Li ions electrochemically with ether-based electrolyte into the van der Waals (vdW) channels of MoS2, which successfully avoids the decomposition of MoS2 at low potentials. The co-intercalation of Li+ and the ether solvent into MoS2 makes a first-order phase transformation, forming a superlattice phase, which preserves the layered structure and hence enables the exfoliation of bulk 2H-MoS2 into bilayer nanosheets with 1T-phase. Compared with the pristine 2H-MoS2, the bilayer 1T-MoS2 nanosheets exhibit better electrocatalytic performance for the hydrogen evolution reaction (HER). This facile method should be easily extended to the exfoliation of various transition metal dichalcogenides (TMDs). [ABSTRACT FROM AUTHOR]

The growing interest in hybrid (aqueous–organic) electrolytes for electrochemical energy storage is due to their wide stability window, improved safety, and ease of assembly that does not require a moisture-free atmosphere. When it comes to applications in electrochemical capacitors, hybrid electrolytes are expected to fill the gap between high-voltage organic systems and their high discharge rate aqueous counterparts. This article discusses the potential applicability of aqueous–organic electrolytes utilizing water/N,N-dimethylacetamide (DMAc) solvent mixture, and sodium perchlorate as a source of charge carriers. The hydrogen bond formation between H2O and DMAc (mole fraction xDMAc = 0.16) is shown to regulate the original water and cation solvation structure, thus reducing the electrochemical activity of the primary aqueous solution both in the hydrogen (HER) and oxygen (OER) evolution reactions region. As a result, an electrochemical stability window of 3.0 V can be achieved on titanium electrodes while providing reasonable ionic conductivity of 39 mS cm−1 along with the electrolyte's flame retardant and anti-freezing properties. Based on the diagnostic electrochemical studies, the operation conditions for carbon/carbon capacitors have been carefully optimized to adjust the potential ranges of the individual electrodes to the electrochemical stability region. The system with the appropriate electrode mass ratio (m+/m− = 1.51) was characterized by a wide operating voltage of 2.0 V, gravimetric energy of 13.2 Wh kg−1, and practically a 100% capacitance retention after 10,000 charge–discharge cycles. This translates to a significant rise in the maximum energy of 76% when compared to the aqueous counterpart. Additionally, reasonable charge–discharge rates and anti-freeze properties of the developed electrolyte enable application in a broad temperature range down to −20 °C, which is demonstrated as well. [ABSTRACT FROM AUTHOR]

The use of two-dimensional (2D) layered metal-organic frameworks (MOFs) as self-sacrificial templates has been proven to be a successful method to create high-efficiency Selenium (Se)-containing electrocatalysts for overall water splitting. Herein, two strategies are then utilized to introduce Se element into the Co–Fe MOF, one being the etching of as-prepared MOF by SeO2 solution, and the other, the replacing of SCN− with SeCN− as the construction unit. The electrochemical activity of the pristine 2D MOF and their calcinated derivatives for catalyzing the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is evaluated and further discussed. It is found that the effect of introducing Se on improving electrochemical catalytic activity is significant for the HER process. Specifically, the calcinated derivative in the replacing method exhibits an overpotential of 235 mV for HER and 270 mV for OER at a current density of 10 mA/cm2. For comparing the two methods of introducing Se element into MOF, similar electrocatalytic activity can be achieved on the their calcinated derivatives. The high electrochemical performance of 2D CoFe-MOF derivatives may be resulted from the unique 2D hierarchical porous structure and strong synergistic effect between different components in the material. [ABSTRACT FROM AUTHOR]

Using the electrochemical technology to split water molecules to produce hydrogen is the key to obtain green hydrogen for solving the energy crisis. The large-scale application of hydrogen evolution reaction (HER) in water dissociation requires a highly active catalyst. In this paper, the highly dispersed PtCo bimetallic nanoparticles loading on MXene (PtCo/MXene) were prepared by using a step-to-step reduction strategy. The mentioned PtCo/MXene catalyst exhibits a high current density of −100 mA/cm2 in an acidic medium with just a 152 mV overpotential. In addition, the PtCo/MXene catalyst also displays a superior stability. Computational analysis and experimental testing demonstrate that the electronic interaction between Pt and Co can effectively modify the electronic structure of the active site, thereby enhancing the inherent catalytic performance of the material. More importantly, MXene two-dimensional nanosheets can expose more active sites because of their large specific surface area. Furthermore, MXene substrate with excellent electrical conductivity and harmonious interfaces between PtCo and MXene enhance charge transfer efficiency and lower the reaction activation energy. [ABSTRACT FROM AUTHOR]

The development of renewable and affordable energy is crucial for building a sustainable society. In this context, establishing a sustainable infrastructure for renewable energy requires the integration of energy storage, specifically use of renewable hydrogen. The hydrogen evolution reaction (HER) of electrochemical water splitting is a promising method for producing green hydrogen. Recently, two-dimensional nanomaterials have shown great promise in promoting the HER in terms of both fundamental research and practical applications due to their high specific surface areas and tunable electronic properties. Among them, molybdenum disulfide (MoS2), a non-noble metal catalyst, has emerged as a promising alternative to replace expensive platinum-based catalysts for the HER because MoS2 has a high inherent activity, low cost, and abundant reserves. At present, greatly improved activity and stability are urgently needed for MoS2 to enable wide deployment of water electrolysis devices. In this regard, efficient strategies for precisely modifying MoS2 are of interest. Herein, the progress made with MoS2 as an HER catalyst is reviewed, with a focus on modification strategies, including phase engineering, morphology design, defect engineering, heteroatom doping, and heterostructure construction. It is believed that these strategies will be helpful in designing and developing high-performance and low-cost MoS2-based catalysts by lowering the charge transfer barrier, increasing the active site density, and optimizing the surface hydrophilicity. In addition, the challenges of MoS2 electrocatalysts and perspectives for future research and development of these catalysts are discussed. [ABSTRACT FROM AUTHOR]

Developing highly active and durable platinum-based catalysts is crucial for electrochemical renewable energy conversion technologies but the limited supply and high cost of platinum have hindered their widespread implementation. The incorporation of non-noble metals, particularly copper, into Pt catalysts has been demonstrated as an effective solution to reduce Pt consumption while further promoting their performance, making them promising for various electrocatalytic reactions. This review summarizes the latest advances in PtCu-based alloy catalysts over the past several years from both synthetic and applied perspectives. In the synthesis section, the selection of support and reagents, synthesis routes, as well as post-treatment methods at high temperatures are reviewed. The application section focuses not only on newly proposed electrochemical reactions such as nitrogen-related reactions and O2 reduction but also extends to device-level applications. The discussion in this review aims to provide further insights and guidance for the development of PtCu electrocatalysts for practical applications. [ABSTRACT FROM AUTHOR]

The development of an efficient and stable electrocatalyst for the hydrogen evolution reaction (HER), based on earth‐abundant components, represents a crucial step toward cost‐effective and environmentally friendly hydrogen production. This study presents the utilization of a dinuclear copper catalyst, denoted as [Cu‐Gly‐SB] (Complex 1), for HER under both aqueous and non‐aqueous conditions. In non‐aqueous settings, the catalyst achieves excellent HER performance, requiring only a 270 mV overpotential when acetic acid is used as the proton donor. Notably, in fully aqueous conditions, complex 1 attains a remarkable current density of 18.8 mA ⋅ cm−2 at −0.7 V vs. RHE in cyclic voltammetry. The kobs value of ≈2.7×104 s−1 in aqueous solution at pH 7.0 further underlines the superior catalytic performance of 1, outperforming most non‐noble‐metal molecular catalysts functioning in fully aqueous solutions. The robust stability of 1 is demonstrated through controlled potential electrolysis (CPE) over a span of 48 hours, achieving an impressive catalytic current of 11.0 mA ⋅ cm−2 at −0.39 V. Moreover, the catalytic current gradually increases with higher reduction potentials, reaching a substantial 100 mA ⋅ cm−2 at an overpotential of 590 mV during CPE >48 hours. Thorough characterizations further confirm the molecular nature of the catalyst. [ABSTRACT FROM AUTHOR]

This study reported a multi–functional Co0.45Fe0.45Ni0.9–MOF/NF catalyst for oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and overall water splitting, which was synthesized via a novel shape–preserving two–step hydrothermal method. The resulting bowknot flake structure on NF enhanced the exposure of active sites, fostering a superior electrocatalytic surface, and the synergistic effect between Co, Fe, and Ni enhanced the catalytic activity of the active site. In an alkaline environment, the catalyst exhibited impressive overpotentials of 244 mV and 287 mV at current densities of 50 mA cm−2 and 100 mA cm−2, respectively. Transitioning to a neutral environment, an overpotential of 505 mV at a current density of 10 mA cm−2 was achieved with the same catalyst, showing a superior property compared to similar catalysts. Furthermore, it was demonstrated that Co0.45Fe0.45Ni0.9–MOF/NF shows versatility as a bifunctional catalyst, excelling in both OER and HER, as well as overall water splitting. The innovative shape–preserving synthesis method presented in this study offers a facile method to develop an efficient electrocatalyst for OER under both alkaline and neutral conditions, which makes it a promising catalyst for hydrogen production by water splitting. [ABSTRACT FROM AUTHOR]

Doping foreign metal atoms into the substrate of transition metal dichalcogenides (TMDs) enables the formation of diverse atomic structure configurations, including isolated atoms, chains, and clusters. Therefore, it is very important to reasonably control the atomic structure and determine the structure–activity relationship between the atomic configurations and the hydrogen evolution reaction (HER) performance. Although numerous studies have indicated that doping can yield diverse atomic structure configurations, there remains an incomplete understanding of the relationship between atomic configurations within the lattice of TMDs and their performance. Here, diverse atomic structure configurations of adsorptive doping, substitutional doping, and TMDs alloys are summarized. The structure–activity relationship between different atomic configurations and HER performance can be determined by micro-nanostructure devices and density functional theory (DFT) calculations. These diverse atomic structure configurations are of great significance for activating the inert basal plane of TMDs and improving the catalytic activity of HER. Finally, we have summarized the current challenges and future opportunities, offering new perspectives for the design of highly active and stable metal-doped TMDs catalysts. [ABSTRACT FROM AUTHOR]

The electrocatalytic activity of a new composite material based on η-carbide Nb3(Fe, Al)3C in the hydrogen evolution reaction from acidic and alkaline solutions is studied. The composite was obtained by spark plasma sintering of mechanically alloyed niobium, aluminum, and graphite powders in steel containers in petroleum ether, followed by etching in an alkaline solution or in a hydrofluoric acid solution. The composite consists of 78 wt % Nb3(Fe, Al)3C, 19 wt % Nb5Al3Cx, and 3 wt % graphite; it has a layered structure with a layer thickness of the Nb5Al3Cx phase of 50–70 nm. In terms of the magnitudes of overpotential in the hydrogen evolution reaction, the resulting composite is superior to undoped Nb2CTx and Nb4C3Tx. [ABSTRACT FROM AUTHOR]

An efficient electrocatalyst is indispensable to significantly reduce energy consumption and accelerate the conversion efficiency of water splitting. In this work, the honeycomb-like porous MoCo alloy on nitrogen-doped three-dimensional (3D) porous graphene substrate (Mo0.3Co0.7@NPG) has been synthesized from the annealing of layered double hydroxide (MoCo-LDH@NPG). Especially, the Mo0.3Co0.7@NPG exhibits low hydrogen evolution overpotential of 75 mV (10 mA·cm–2) and a Tafel slope of 69.9 mV·dec–1, which can be attributed to highly conductive NPG substrate, the unique nanostructure and the synergistic effect of Mo and Co. Moreover, the Mo0.3Co0.7@NPG can maintain the original morphology and high catalytic activity after 50-h stability test. This work proposes a general strategy to synthesize a multi-element alloy on conductive substrates with high porosity for electrocatalytic reaction. 摘要: 高效的电催化剂可以显著降低电解水的能耗和提高转化效率。本项工作以MoCo双金属氢氧化物作为前驱体, 在三维(3D) 氮掺杂多孔石墨烯衬底上合成了蜂窝状多孔MoCo合金(Mo0.3Co0.7@NPG)。在析氢反应中, Mo0.3Co0.7@NPG的析氢过电位为75 mV (10 mA cm–2), Tafel斜率为69.9 mV dec–1。Mo0.3Co0.7@NPG具有优异的电化学性能主要归功于NPG衬底的高导电性、MoCo合金独特的纳米结构以及Mo和Co的协同作用。此外, 经过50 h的稳定性测试, Mo0.3Co0.7@NPG仍能保持原有的形貌和较高的催化活性。因此, 本项工作对于在高孔隙率导电基板上合成高效的多元素合金电催化剂提供了一种思路。 [ABSTRACT FROM AUTHOR]

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In this study, we explored the surface modification of a glassy carbon electrode through the electrografting of 4-Aminophenyl phosphate, which features heteroatoms and ionic properties. The electrochemical grafting process involves reducing in situ-generated diazonium derivatives. The primary objective of this research was to immobilize organic layers and assess their electrochemical and surface properties. Subsequently, the generated surface serves as a template for the electrochemical growth of Pd and Co nanoparticles on functionalized electrodes. The electrocatalytic performances of these hybrid electrodes in driving the hydrogen evolution reaction were investigated. The obtained results indicate an enhancement in the electrocatalytic activity of the modified electrodes, where lower overpotential and higher stability were observed when the catalyst was electrodeposited onto the attached ionic layer. These findings highlight the synergistic effect between the attached phenyl phosphate moieties and electrocatalysts. [ABSTRACT FROM AUTHOR]

The 3D NiMoxCo2–xO4 (x ≤ 0.06) chestnut-like spinel oxide nanoparticles (CNSPs) grown on Ni foam were effectively prepared hydrothermally. The formation of Ni–Co CNSPs was confirmed by the XRD powder pattern, which exhibited a pure cubic spinel oxide structure without undesired phases. All ratios revealed a broadened peak representing a small crystal size (12.8–17.5 nm) range. The chestnut-like CNSPs were presented by FE-SEM, SEM, TEM, and HR-TEM analysis. The chemical composition of the products was confirmed by EDX. The 3D NiMoxCo2–xO4 (x = 0.04) CNSP electrocatalyst exhibited hydrogen evolution reaction (HER) activity as evidenced by 0.224 V overpotential, Tafel slope 61.9 mV/dec, and high stability for 36 h of chronopotentiometry techniques. The surface and electrochemical characterization revealed that 4.0% Mo-doped exhibits improved HER activity due to significantly higher electrochemical surface area and accelerated charge-transfer kinetics at the semiconductor electrolyte interface. Density functional theory is employed to investigate the impact of Mo dopants on the HER performance. This study shows how both hydrogen and water molecules adhere to the surface of Mo-doped NiCo2O4 slab structures. The findings indicate that introducing Mo dopants leads to an augmentation of chemical activity through water adsorption, resulting in an enhanced electrocatalytic process and improved HER activity up to a specific Mo concentration, and their impact on spin-dependent electronic structure characteristics is revealed by the density of states spectra. This work not only gives insights into low-metal-cost materials for efficient and durable HER electrocatalysts, but it also provides a successful showcase model catalyst for in-depth mechanistic insights into electrochemical HER processes and their industrial applications in the future. [ABSTRACT FROM AUTHOR]

Transition metal phosphides (TMPs) have been widely studied for water decomposition for their monocatalytic property for anodic or cathodic reactions. However, their bifunctional catalytic activity still remains a major challenge. Herein, hexagonal nickel-cobalt bimetallic phosphide nanoneedles with 1–3 μm length and 15–30 nm diameter supported on NF (NixCo2−xP NDs/NF) with adjusted electron structure have been successfully prepared. The overall alkaline water electrolyzer composed of the optimal anode (Ni0.67Co1.33P NDs/NF) and cathode (Ni1.01Co0.99P NDs/NF) provide 100 mA cm−2 at 1.62 V. Gibbs Free Energy for reaction paths proves that the active site in the hydrogen evolution reaction (HER) is Ni and the oxygen evolution reaction (OER) is Co in NixCo2−xP, respectively. In the HER process, Co-doping can result in an apparent accumulation of charge around Ni active sites in favor of promoting HER activity of Ni sites, and ΔGH* of 0.19 eV is achieved. In the OER process, the abundant electron transfer around Co-active sites results in the excellent ability to adsorb and desorb *O and *OOH intermediates and an effectively reduced ∆GRDS of 0.37 eV. This research explains the regulation of electronic structure change on the active sites of bimetallic materials and provides an effective way to design a stable and effective electrocatalytic decomposition of alkaline water. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Rare Metals is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Developing efficient and robust hydrogen evolution reaction (HER) catalysts for scalable and sustainable hydrogen production through electrochemical water splitting is strategic and challenging. Herein, heterogeneous Mo8O26‐NbNxOy supported on N‐doped graphene (defined as Mo8O26‐NbNxOy/NG) is synthesized by controllable hydrothermal reaction and nitridation process. The O‐exposed Mo8O26 clusters covalently confined on NbNxOy nanodomains provide a distinctive interface configuration and appropriate electronic structure, where fully exposed multiple active sites give excellent HER performance beyond commercial Pt/C catalyst in pH‐universal electrolytes. Theoretical studies reveal that the Mo8O26‐NbNxOy interface with electronic reconstruction affords near‐optimal hydrogen adsorption energy and enhanced initial H2O adsorption. Furthermore, the terminal O atoms in Mo8O26 clusters cooperate with Nb atoms to promote the initial H2O adsorption, and subsequently reduce the H2O dissociation energy, accelerating the entire HER kinetics. [ABSTRACT FROM AUTHOR]

Developing efficient and robust hydrogen evolution reaction (HER) catalysts for scalable and sustainable hydrogen production through electrochemical water splitting is strategic and challenging. Herein, heterogeneous Mo8O26‐NbNxOy supported on N‐doped graphene (defined as Mo8O26‐NbNxOy/NG) is synthesized by controllable hydrothermal reaction and nitridation process. The O‐exposed Mo8O26 clusters covalently confined on NbNxOy nanodomains provide a distinctive interface configuration and appropriate electronic structure, where fully exposed multiple active sites give excellent HER performance beyond commercial Pt/C catalyst in pH‐universal electrolytes. Theoretical studies reveal that the Mo8O26‐NbNxOy interface with electronic reconstruction affords near‐optimal hydrogen adsorption energy and enhanced initial H2O adsorption. Furthermore, the terminal O atoms in Mo8O26 clusters cooperate with Nb atoms to promote the initial H2O adsorption, and subsequently reduce the H2O dissociation energy, accelerating the entire HER kinetics. [ABSTRACT FROM AUTHOR]

The establishment of facile synthetic routes to engineer covalent organic frameworks (COFs) with fully conjugated structure and excellent stability is highly desired for practical applications in optoelectronics and photocatalysis. Herein, a novel linkage conversion strategy is reported to prepare crystalline thiadiazole‐linked COFs via thionation, cyclization, and oxidation of N‐acylhydrazole bonds with Lawesson's reagent (LR). The as‐prepared thiadiazole‐linked COFs not only remain porosity and crystallinity, but enhance its chemical stability. Furthermore, thiadiazole‐linked COFs are more favorable to lower exciton binding energy and promote π‐electron delocalization over the whole reticular framework than N‐acylhydrazone‐linked COFs. Notably, the extended π‐conjugation structure and decent crystallinity of the resulting TDA‐COF are reflected by its higher photocatalytic H2 evolution rate (61.3 mmol g−1 in 5 h) in comparison with that (7.5 mmol g−1) of NAH‐COF. [ABSTRACT FROM AUTHOR]

A novel approach was used to synthesize the 5,10,15,20-tetrakis (p-thiophenol) porphyrin (TPTH-P) (2), which involved the demethylation of tetra (p-anisole) porphyrin (1) in the presence of ZnCl2 as a catalyst and DMF as a solvent at 100 °C. The demethylation step was followed by an acidification step with concentrated H2SO4 to yield the desired TPTH-P (2) in an almost quantitative yield (95%). The chemical structure of the synthesized porphyrin thiol (TPTH-P) (2) was verified through spectroscopic techniques (NMR, IR, UV-Vis). The catalytic activity of TPTH-P in the hydrogen evolution reaction (HER) was investigated in 0.1 M of H2SO4 and 1 M of KNO3. A self-assembled monolayer (SAM) of TPTH-P was formed on a gold electrode. The immersion time during SAM formation and the electrochemical activation cycles in H2SO4 were found to be important to enhancing the activity of the Au-TPTH-P electrode in the HER. Contact angle measurements and electrochemical techniques, including cyclic voltammetry (CV), linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS), and chronoamperometry, were used to characterize and evaluate the electrochemical activities of the SAM. [ABSTRACT FROM AUTHOR]

Herein, the density functional theory is used to study the structural, mechanical, electrical, optical, and hydrogen evolution reaction (HER) properties of monolayer structures (α,β)–S2C2N2$\left(\right. \alpha , \beta \left.\right) – \left(\text{S}\right)_{2} \left(\text{C}\right)_{2} \left(\text{N}\right)_{2}$ and (α,β)–SCN/CN$\left(\right. \alpha , \beta \left.\right) – \text{SCN} / \text{CN}$. They are claimed to be stable monolayer structures by phonon dispersion and ab initio molecular dynamics (AIMD). Compared to graphene (≈340 N m−1), the (α,β)–SCN/CN$\left(\right. \alpha , \beta \left.\right) – \text{SCN} / \text{CN}$ shows a higher Young's modulus (≈429, 414 N m−1). Moreover, the piezoelectric stress coefficient of α‐SCN/CN$\text{SCN} / \text{CN}$ (d11$d_{11}$=2.65 pm V−1) is comparable with bulk piezoelectric α‐quartz (d11$d_{11}$=2.3 pm V−1). Exciton effect at M point causes redshift and enhancement of light absorption of α‐SCN/CN$\text{SCN} / \text{CN}$ and β–SCN/CN$\beta – \text{SCN} / \text{CN}$. The overpotential of β–SCN/CN$\beta – \text{SCN} / \text{CN}$ is only –0.072 V. Besides, the (α,β)–SCN/CN$\left(\right. \alpha , \beta \left.\right) – \text{SCN} / \text{CN}$ gives a small effective electron mass of about 0.2(m0). It is worth mentioning that the monolayer structures (α,β)–S2C2N2$\left(\right. \alpha , \beta \left.\right) – \left(\text{S}\right)_{2} \left(\text{C}\right)_{2} \left(\text{N}\right)_{2}$ show the semimetal phases. Due to the unique semimetal phase, the absorption of β–S2C2N2$\beta – \left(\text{S}\right)_{2} \left(\text{C}\right)_{2} \left(\text{N}\right)_{2}$ has an excellent performance in the near‐infrared (NIR) region. It can be enhanced at the NIR region and extended to the middle infrared region when applying tensile stress. These results provide more choices for 2D materials in electrocatalysis, piezoelectric sensors, visible light devices, and infrared photodetectors. [ABSTRACT FROM AUTHOR]

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Highlights: S-doped CuO nanorod arrays (S-CuO/CF) constructed by sulfur leaching and oxidative remodeling strategy require only 1.23 and 1.33 V versus hydrogen evolution reaction (HER) to provide glycerol oxidation currents of 100 and 500 mA cm−2. S-CuO/CF shows satisfactory performance (at 100 mA cm−2, Vcell = 1.37 V) assembled as the anode in asymmetric coupled electrolytic cell of glycerol oxidation reaction and HER. The study identifies the key factors involved in the GOR reaction pathway, which include the C–C bond breaking and lattice oxygen deintercalation steps. Glycerol (electrochemical) oxidation reaction (GOR) producing organic small molecule acid and coupling with hydrogen evolution reaction is a critical aspect of ensuring balanced glycerol capacity and promoting hydrogen generation on a large scale. However, the development of highly efficient and selective non-noble metal-based GOR electrocatalysts is still a key problem. Here, an S-doped CuO nanorod array catalyst (S-CuO/CF) constructed by sulfur leaching and oxidative remodeling is used to drive GOR at low potentials: It requires potentials of only 1.23 and 1.33 V versus RHE to provide currents of 100 and 500 mA cm−2, respectively. Moreover, it shows satisfactory comprehensive performance (at 100 mA cm−2, Vcell = 1.37 V) when assembled as the anode in asymmetric coupled electrolytic cell. Furthermore, we propose a detailed cycle reaction pathway (in alkaline environment) of S-doped CuO surface promoting GOR to produce formic acid and glycolic acid. Among them, the C–C bond breaking and lattice oxygen deintercalation steps frequently involved in the reaction pathway are the key factors to determine the catalytic performance and product selectivity. This research provides valuable guidance for the development of transition metal-based electrocatalysts for GOR and valuable insights into the glycerol oxidation cycle reaction pathway. [ABSTRACT FROM AUTHOR]

The performance of lead-acid batteries could be significantly increased by incorporating carbon materials into the negative electrodes. In this study, a modified carbon material developed via a simple high-temperature calcination method was employed as a negative electrode additive, and we have named it as follows: N-doped chitosan-derived carbon (NCC). The performance of this material was compared with a control battery containing activated carbon (AC). X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman spectroscopy were engaged in analyzing the crystal structure and morphology of the material. Afterwards, the electrochemical and battery performance was examined through cyclic voltammetry (CV), linear voltammetry (LSV) and constant current charge-discharge testing. Markedly, the electrode plate containing 1 wt.% NCC indicates the highest specific capacity (106.48 F g−1) as compared to the control battery, which is 1.56 times higher than the AC electrode plate and 4.75 times higher than the blank electrode plate. The linear voltammetry shows that the hydrogen precipitation current density of the 1 wt.% NCC electrode plate is only −0.028 A cm−2, a much higher value than that of the AC electrode plate. In addition, the simulated battery containing 1 wt.% NCC has a cycle life of 4324 cycles, which is 2.36 times longer than that of the same amount of additive AC battery (1834 cycles) and 5.34 times longer than that of the blank battery (809 cycles). In summary, NCC carbon has the advantage of extending the life of lead-acid batteries, rendering it a promising candidate for lead-acid battery additives. [ABSTRACT FROM AUTHOR]

The design and development of efficient and low-cost electrocatalysts for both anodic (oxygen evolution reaction (OER)/hydrazine oxidation reaction (HzOR)) and cathodic (hydrogen evolution reaction (HER)) reactions are the major challenges for cleaner hydrogen production. Especially, the fabrication of electrocatalysts with abundant electrochemically active sites through simple synthetic routes is of great interest to draw excellent catalytic efficiency. This report provides a strategy to prepare CoS2–MoS2 heterostructures and spheroid-like CoS2 through the sulfurization reaction from the common Co3O4 nanocube precursor in the presence and absence of the molybdenum precursor, respectively. The as-prepared CoS2–MoS2 (25) heterostructure (prepared with 25 mg of Co3O4) shows excellent HER activity in 1 M KOH by delivering a current density of 10 mA/cmgeo2 at an overpotential of 92.5 ± 3.1 mV. The observed enhancement in the HER activity is attributed to the improved water dissociation kinetics at the abundant interfacial area shared between the two components of the heterostructure. Besides, spheroid-like CoS2 shows good OER and hydrazine oxidation reaction (HzOR) activity owing to the high electrochemically active surface area. In addition, the alkaline electrolyzer (HER//OER) constructed using the CoS2–MoS2 (25) heterostructure and spheroid-like CoS2 as the cathode and anode, respectively, delivers a current density of 10 mA/cmgeo2 at a cell potential of 1.67 V. Furthermore, the hydrazine-assisted electrolyzer (HER//HzOR) displays a low cell potential of 0.53 V to attain the same current density along with excellent durability up to 30 h. [ABSTRACT FROM AUTHOR]

Vertically stacking two-dimensional (2D) materials with small azimuthal deviation or lattice mismatch generate distinctive global structural periodicity and symmetry, revealed as the moiré superlattices (MSLs). Manipulating the interlayer twist angle enables the modification of the electronic structure of 2D materials to explore the advanced applications. Although extraordinary progress has been achieved in the unique structure and emergent properties of MSLs, the investigation of the catalytic applications of MSLs materials is still in its infancy. It is therefore very urgent to summarize the advanced development of MSLs in the field of catalysis. In this review, we firstly summarize the advanced fabrication and high-resolution characterization techniques of the MSLs materials, as well as their novel properties related to catalysis represented by electrocatalytic hydrogen evolution reaction (HER). Then, all the MSLs materials such as MoS2, WS2, and Ru serving as electrocatalysts for HER are further reviewed in detail. Finally, we outline the current challenges as well as the experimental and theoretical strategies to advance the development of function-oriented MSLs materials for catalysis. This review aims to provide profound insight into the wide applications of this novel material platform in catalytic field. [ABSTRACT FROM AUTHOR]

Highlights: A hierarchical interconnected NiMoN (HW-NiMoN-2h) was successfully prepared based on a rational combination of hydrothermal and water bath processes. HW-NiMoN-2h exhibited high hydrogen evolution reaction (HER) activity due to its large specific surface area and good stability due to its enhanced mechanical strength. In 1 M KOH seawater, HW-NiMoN-2h delivered current density of 1 A cm−2 for HER at an overpotential of 130 mV and showed excellent stability over 70 h at 1 A cm−2. NiMo-based nanostructures are among the most active hydrogen evolution reaction (HER) catalysts under an alkaline environment due to their strong water dissociation ability. However, these nanostructures are vulnerable to the destructive effects of H2 production, especially at industry-standard current densities. Therefore, developing a strategy to improve their mechanical strength while maintaining or even further increasing the activity of these nanocatalysts is of great interest to both the research and industrial communities. Here, a hierarchical interconnected NiMoN (HW-NiMoN-2h) with a nanorod-nanowire morphology was synthesized based on a rational combination of hydrothermal and water bath processes. HW-NiMoN-2h is found to exhibit excellent HER activity due to the accomodation of abundant active sites on its hierarchical morphology, in which nanowires connect free-standing nanorods, concurrently strengthening its structural stability to withstand H2 production at 1 A cm−2. Seawater is an attractive feedstock for water electrolysis since H2 generation and water desalination can be addressed simultaneously in a single process. The HER performance of HW-NiMoN-2h in alkaline seawater suggests that the presence of Na+ ions interferes with the reation kinetics, thus lowering its activity slightly. However, benefiting from its hierarchical and interconnected characteristics, HW-NiMoN-2h is found to deliver outstanding HER activity of 1 A cm−2 at 130 mV overpotential and to exhibit excellent stability at 1 A cm−2 over 70 h in 1 M KOH seawater. [ABSTRACT FROM AUTHOR]

Recently, two‐dimensional transition metal dichalcogenides (TMDs) demonstrated their great potential as cost‐effective catalysts in hydrogen evolution reaction. Herein, we systematically summarize the existing defect engineering strategies, including intrinsic defects (atomic vacancy and active edges) and extrinsic defects (metal doping, nonmetal doping, and hybrid doping), which have been utilized to obtain advanced TMD‐based electrocatalysts. Based on theoretical simulations and experimental results, the electronic structure, intermediate adsorption/desorption energies and possible catalytic mechanisms are thoroughly discussed. Particular emphasis is given to the intrinsic relationship between various types of defects and electrocatalytic properties. Furthermore, current opportunities and challenges for mechanical investigations and applications of defective TMD‐based catalysts are presented. The aim herein is to reveal the respective properties of various defective TMD catalysts and provide valuable insights for fabricating high‐efficiency TMD‐based electrocatalysts. [ABSTRACT FROM AUTHOR]

Based on the DFT calculations, two-dimensional (2D) R-graphyne has been demonstrated to have high stability and good conductivity, which can be conducive to the relevant electrocatalytic activity of the material. Different from the poor graphene, R-graphyne, which is completely composed of anti-aromatic structural units, can exhibit certain HER catalytic activity. In addition, doping the TM atoms in Group VIIIB can be considered an effective strategy to enhance the HER catalytic activity of R-graphyne. Particularly, Fe@R-graphyne, Os@R-graphyne, Rh@R-graphyne and Ir@R-graphyne can exhibit higher HER catalytic activities due to the formation of more active sites. Usually, the shorter the distance between the TM and C atoms is, the better the HER activity of the C-site is. Furthermore, doping Ni and Rh atoms of Group VIIIB can significantly improve the OER catalytic performance of R-graphyne. It can be found that ΔGO* can be used as a good descriptor for the OER activities of TM@R-graphyne systems. Both Rh@R-graphyne and Ni@R-graphyne systems can exhibit bifunctional electrocatalytic activities for HER/OER. In addition, all the relevant catalytic mechanisms are analyzed in detail. This work not only provides nonprecious and highly efficient HER/OER electrocatalysts, but also provides new ideas for the design of carbon-based electrocatalysts. [ABSTRACT FROM AUTHOR]

Semiconductors-based heterogeneous photocatalytic water splitting has been extensively studied, but it still remains challenging to accelerate the separation of electron—hole pairs and facilitate the reaction kinetics. Here we report a general strategy to fabricate highly efficient Pt/TiO2 photocatalyst by coupling the Pt co-catalysts and surface oxygen vacancies (VO) of TiO2. TiO2 was pre-modified with alkali or alkaline earth metals ion solutions, which produce a large number of surface hydroxyl on TiO2. Subsequently, the photodeposited Pt sub-nanoparticles substitute surface hydroxyl and induce surface VO on TiO2. The coupling of Pt and surface VO on TiO2 can accelerate the extraction of photo-charges through the interaction of Pt—VO—Ti bonds and reduce the hydrogen evolution barrier, thereby promoting the photocatalytic activity. The synthesized Pt-VO-TiO2 sample exhibits a photocatalytic hydrogen evolution activity as high as 1.5 L·g−1·h−1, which is 2.2 times that of traditional Pt/TiO2. Our findings in-depth understand the synergistic effect of co-catalysts and defects on photocatalysis and open up new possibilities for achieving robust photocatalytic water splitting. [ABSTRACT FROM AUTHOR]

The sufficient utilization of Mott-Schottky effect for boosting alkaline hydrogen evolution reaction (HER) depends upon scale minimizing of interface components and exposure maximizing of Mott-Schottky interface. Here, a self-standing porous tubular Mott-Schottky electrocatalyst is constructed by a self-template etching strategy, where amorphous WOx (a-WOx) nano-matrix connects Co nanoparticles. This novel "Janus" electrocatalyst maximizes the Mott-Schottky effect by not only providing a highly exposed micro interface, but also simultaneously accelerating the water dissociation and optimizing the hydrogen desorption process. Experimental findings and theoretical calculations reveal that Co/a-WOx Mott-Schottky heterointerface triggers the electron redistribution and a build-in electric field, which can not only optimize the adsorption energy of the reaction intermediates, but also facilitate the charge transfer. Thus, Co/a-WOx requires an overpotential of only 36.3 mV at 10 mA·cm−2 and shows a small Tafel slope of 53.9 mV·dec−1 as well as an excellent 200-h long-term stability. This work provides a novel design strategy for maximizing the Mott-Schottky effect on promoting alkaline HER. [ABSTRACT FROM AUTHOR]

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Cu-oxide nanophases (CuO, Cu2O, Cu0) constitute highly potent nanoplatforms for the development of efficient Artificial Photosynthesis catalysts. The highly reducing conduction band edge of the d-electrons in Cu2O dictates its efficiency towards CO2 reduction under sunlight excitation. In the present review, we discuss aspects interlinking the stability under photocorrosion of the (CuO/Cu2O/Cu0) nanophase equilibria, and performance in H2-production/CO2-reduction. Converging literature evidence shows that, because of photocorrosion, single-phase Cu-oxides would not be favorable to be used as a standalone cathodic catalyst/electrode; however, their heterojunctions and the coupling with proper partner materials is an encouraging approach. Distinction between the role of various factors is required to protect the material from photocorrosion, e.g., use of hole scavengers/electron acceptors, band-gap engineering, nano-facet engineering, and selectivity of CO2-reduction pathways, to name a few possible solutions. In this context, herein we discuss examples and synthesis efforts that aim to clarify the role of interfaces, faces, and phase stability under photocatalytic conditions. [ABSTRACT FROM AUTHOR]

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Electrocatalytic water splitting as a green chemical process to evolve H2 has increasingly attracted attention. Using fresh water as the proton source not only increases the cost but also significantly hinders the wide applications of electrocatalysis in H2 production. Instead, seawater is more competitive compared to fresh water from the economic aspects, but more challenging from the technical aspects. Technically, insoluble solids and chloride ions in seawater significantly affect the electrocatalytic activity and stability of catalysts. Great efforts have been spared to develop highly effective electrocatalysts for seawater splitting, and various strategies have been raised. Herein, we categorized and discussed recently reported composites applied in electrocatalytic seawater splitting. Future perspectives for the advancement of seawater-based electrocatalysts have been proposed at the end. We hope to provide some new understanding and methods for the reasonable construction of state-of-the-art electrocatalysts to tackle the challenges of seawater splitting. 摘要: 电催化水裂解作为一种绿色的制氢过程受到人们的关注。使用淡水作为电解液不仅增加了成本, 而且严重阻碍了电催化在制氢中的广泛应用。相反, 海水在经济方面比淡水更有竞争力, 但在技术方面更具挑战性。从技术上讲, 海水中的不溶性固体和氯离子会严重影响催化剂的电催化活性和稳定性。目前, 人们一直在努力开发高效的海水裂解电催化剂, 并提出了各种策略。在此, 我们对最近报道的用于电催化海水裂解的复合材料进行了分类和讨论。最后, 对海水基电催化剂的发展前景进行了展望。我们希望可以为合理构建最先进的电催化剂以应对海水分解的挑战提供一些新的认识和方法。 [ABSTRACT FROM AUTHOR]

Hydrogen evolution reaction (HER) is of high priority at present. Existing research has involved the use of noble metals as catalysts for HER, thus putting an urgency to develop low-cost materials to replace them. In this work, metal-free Oleic acid functionalized Carbon Dots have been for the first time reported to have outstanding activity for HER. Electrochemical investigation reveals excellent catalytic performance with overpotential of 1 mV at a current density of − 5 mA cm - 2 . The performance at this range marks a significant milestone and paves the way for a sustainable future of metal-free catalysis. [ABSTRACT FROM AUTHOR]