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Journal ArticleDOI: 10.1039/D0DT04248J

Ultrafine CoRu alloy nanoparticles in situ embedded in Co4N porous nanosheets as high-efficient hydrogen evolution electrocatalysts.

02 Mar 2021-Dalton Transactions (Royal Society of Chemistry (RSC))-Vol. 50, Iss: 8, pp 2973-2980
Abstract: The development of hydrogen evolution reaction (HER) electrocatalysts with outstanding efficiency and favorable stability at all pH values is of great significance but still a dominating challenge toward the development of electrochemical water-splitting technology Herein, CoRu alloy nanoparticles assembled in Co4N porous nanosheets (named as CoRu@Co4N) have been successfully achieved from Ru(OH)3@Co(OH)2 through a one-step nitridation process Benefiting from the unique structure, inherent alloy properties and strong alloy-support interaction derived from the in situ transformation, the resultant hybrids exhibit superior HER activities over a wide pH range, achieving very low overpotentials of 13 mV, 44 mV and 15 mV at 10 mA cm-2 under alkaline, neutral and acidic conditions, respectively Such activities surpass most reported electrocatalysts and are comparable or even transcendent to commercial Ru/C and Pt/C Furthermore, CoRu@Co4N also exhibits outstanding stability during the accelerated degradation test (ADT) and chronopotentiometry Our work provides a new approach for designing pH-universal Ru-involved HER electrocatalysts with remarkable efficiency and prominent durability

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5 results found

Journal ArticleDOI: 10.1016/J.APCATB.2021.120601
Meilin Zhang1, Yeqing Zhang1, Lei Ye1, Buwen Guo2  +1 moreInstitutions (2)
Abstract: It is highly desirable to cut down the electron transfer resistance, improve both site activity and site populations of layered double hydroxides (LDHs) for enhanced electrochemical activity of oxygen evolution reaction (OER). Herein, the hybrid that Co-LDH nanosheets shells grown on Ag nanowires (NWs) cores (Ag@Co-LDH) was constructed and applied as a favorable OER electrocatalyst. The high conductivity of Ag NWs and heterointerface between Ag NWs and Co-LDH gravely accelerate electron transfer. Co-LDH with ultrathin sheet-like structure and abundant grain boundary defects effectively provide lots of active sites. The optimized local environment of Co atoms by Ag dopants and plentiful amorphous regions strongly enhance the intrinsic activity of active site. Therefore, the as-prepared Ag@Co-LDH demonstrates distinguished OER activity with a low overpotential of 217 mV at the current density of 10 mA cm−2, which is superior to most reported advanced OER electrocatalysts and even commercial Ir/C. Moreover, benefiting from the unique structure and stable heterointerface, Ag@Co-LDH also exhibits robust cycling stability and long-term durability proved by accelerated degradation test (ADT) and galvanostatic test, respectively. This finding provides a practical design direction for high-performance LDH-based OER electrocatalysts.

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Topics: Electrocatalyst (51%), Overpotential (50%)

2 Citations

Journal ArticleDOI: 10.1016/J.JPOWSOUR.2021.230600
Zongshan Lin1, Zongshan Lin2, Shilong Liu2, Shilong Liu1  +7 moreInstitutions (4)
Abstract: Developing efficient, robust, and cost-effective catalysts to boost the electrocatalytic properties of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) for overall water splitting is fundamentally important yet very challenging. Herein, we report a facile method to prepare Ru-based aerogels for HER, OER, and water electrolysis. Specifically, Ru aerogel exhibits comparable HER performance with Pt/C, evidenced by a close overpotential at 10 mA cm−2, a smaller Tafel slope, and an outperformed long-term stability. Among a series of RuCo aerogels, the Ru0.7Co0.3 aerogel has the best OER performance superior to the RuO2 benchmark catalyst, with a very small overpotential of 272 mV at 10 mA cm−2, a low Tafel slope value of 41.6 mV dec−1, and the improved long-term durability. The excellent OER performance of the Ru0.7Co0.3 aerogel is mainly attributed to the RuCo synergistic catalytic effect, the abundant oxygen vacancies, and the structural merits of the sample. Notably, in the practical overall water splitting test, the combined Ru and Ru0.7Co0.3 aerogel catalyst outperforms the Pt/C + RuO2 couple. This study can shed light on preparation of metal aerogel-based bifunctional electrocatalyst for overall water splitting and beyond.

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Topics: Water splitting (56.99%), Oxygen evolution (54%), Overpotential (53%) ... show more

Journal ArticleDOI: 10.1039/D1DT01434J
Yanfei Zhong1, Liping Huang1, Qianqian Wu1, Jiacheng Zhang1  +6 moreInstitutions (1)
Abstract: Hydrogen is a promising substitute for non-renewable fossil fuels. Producing hydrogen fuel by electrolyzing water is an effective strategy to address the growing environmental problems. Platinum (Pt) is still the most active electrocatalyst to catalyze the hydrogen evolution reaction (HER) in alkaline media. Herein, we demonstrate that ultrafine candied haws-shaped PtWNi nanoalloys modified with the Ni species (Nin+) could be formed in the alkaline electroactivation process of PtWNi alloys. Notably, the Ni species (Nin+) promoted the decomposition of water and produced hydrogen intermediates, which were then immediately adsorbed on the surface of Pt and recombined into molecular hydrogen. Moreover, these hydrogen intermediates also enhanced the instability of the HO-H bond, leading to an increase in the total activity.

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Topics: Hydrogen (56%), Electrocatalyst (54%), Electrolysis of water (54%) ... show more

Journal ArticleDOI: 10.1016/J.CEJ.2021.131922
Yuyin Fan1, Yanfang Sun2, Xiao Zhang1, Jinxue Guo1Institutions (2)
Abstract: Seeking novel low-cost non-noble metal based electrocatalysts with high efficiency is of great significance to promote industrial application of hydrogen evolution reaction (HER). Herein, we originally demonstrate sulfur on CoFe alloys embedded in nitrogen-doped carbon nanosheets (S-CoFe@NC) catalyst with extremely robust HER activity in neutral media. The present sample exhibits active HER performance with ultralow overpotential of 37 mV at current density of 10 mA cm−2 and Tafel slope of 34 mV dec-1, which is the same as commercial Pt/C. Systemic studies show that strong interaction between bridging Sn2- and CoFe@NC introduces M−Sn2- as the robust catalysis sites for HER, which is also beneficial for the charge exchange. The specific structure of NC nanosheet interconnected network provides structure advantages for easily accessible active sites and fast charge transfer for electrocatalysis. Thus, this work paves a way for the development of new class of sulfur based electrocatalyst with efficient HER performance for neutral water splitting.

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Topics: Overpotential (54%), Electrocatalyst (53%), Water splitting (53%) ... show more

Open accessJournal ArticleDOI: 10.3390/CATAL11111265
21 Oct 2021-Catalysts
Abstract: The forms of boron atoms are many and varied in the structure of transition metal borides (TMBs). The form of boron atoms determines the structure, morphology, and properties of borides. Herein, transition metal monoborides (CrB and WB) with different arrangement of one-dimensional (1D) boron chains were synthesized under high pressures and high temperatures. The 1D boron chains between the interlayers of CrB are parallel to one another, while the 1D boron chains between the interlayers of WB are perpendicular to one another. The morphologies of CrB and WB also show large differences due to the difference in 1D boron chain arrangement. As electrocatalysts for hydrogen evolution reactions (HERs), CrB and WB show good catalysis activity and durability. WB has the smallest overpotential (210 mV) and Tafel slope (90.09 mV dec−1), which is mainly attributed to the intercrossing boron chains improving the electrical properties of WB, as well as the 5d electrons of W being more chemically active. The TOF value of WB is 1.35 s−1, proving that WB has a higher intrinsic catalytic activity during HERs. This work provides a data reference for the development of high-efficiency electrocatalysts.

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Topics: Boron (56%)


54 results found

Journal ArticleDOI: 10.1038/NATURE11475
Steven Chu1, Arun Majumdar1Institutions (1)
16 Aug 2012-Nature
Abstract: Access to clean, affordable and reliable energy has been a cornerstone of the world's increasing prosperity and economic growth since the beginning of the industrial revolution. Our use of energy in the twenty–first century must also be sustainable. Solar and water–based energy generation, and engineering of microbes to produce biofuels are a few examples of the alternatives. This Perspective puts these opportunities into a larger context by relating them to a number of aspects in the transportation and electricity generation sectors. It also provides a snapshot of the current energy landscape and discusses several research and development opportunities and pathways that could lead to a prosperous, sustainable and secure energy future for the world.

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Topics: Energy policy (61%), Energy source (60%), Energy development (60%) ... show more

5,397 Citations

Open accessJournal ArticleDOI: 10.1126/SCIENCE.AAD4998
Zhi Wei Seh1, Zhi Wei Seh2, Zhi Wei Seh3, Jakob Kibsgaard2  +9 moreInstitutions (4)
13 Jan 2017-Science
Abstract: BACKGROUND With a rising global population, increasing energy demands, and impending climate change, major concerns have been raised over the security of our energy future. Developing sustainable, fossil-free pathways to produce fuels and chemicals of global importance could play a major role in reducing carbon dioxide emissions while providing the feedstocks needed to make the products we use on a daily basis. One prospective goal is to develop electrochemical conversion processes that can convert molecules in the atmosphere (e.g., water, carbon dioxide, and nitrogen) into higher-value products (e.g., hydrogen, hydrocarbons, oxygenates, and ammonia) by coupling to renewable energy. Electrocatalysts play a key role in these energy conversion technologies because they increase the rate, efficiency, and selectivity of the chemical transformations involved. Today’s electrocatalysts, however, are inadequate. The grand challenge is to develop advanced electrocatalysts with the enhanced performance needed to enable widespread penetration of clean energy technologies. ADVANCES Over the past decade, substantial progress has been made in understanding several key electrochemical transformations, particularly those that involve water, hydrogen, and oxygen. The combination of theoretical and experimental studies working in concert has proven to be a successful strategy in this respect, yielding a framework to understand catalytic trends that can ultimately provide rational guidance toward the development of improved catalysts. Catalyst design strategies that aim to increase the number of active sites and/or increase the intrinsic activity of each active site have been successfully developed. The field of hydrogen evolution, for example, has seen important breakthroughs over the years in the development of highly active non–precious metal catalysts in acid. Notable advancements have also been made in the design of oxygen reduction and evolution catalysts, although there remains substantial room for improvement. The combination of theory and experiment elucidates the remaining challenges in developing further improved catalysts, often involving scaling relations among reactive intermediates. This understanding serves as an initial platform to design strategies to circumvent technical obstacles, opening up opportunities and approaches to develop higher-performance electrocatalysts for a wide range of reactions. OUTLOOK A systematic framework of combining theory and experiment in electrocatalysis helps to uncover broader governing principles that can be used to understand a wide variety of electrochemical transformations. These principles can be applied to other emerging and promising clean energy reactions, including hydrogen peroxide production, carbon dioxide reduction, and nitrogen reduction, among others. Although current paradigms for catalyst development have been helpful to date, a number of challenges need to be successfully addressed in order to achieve major breakthroughs. One important frontier, for example, is the development of both experimental and computational methods that can rapidly elucidate reaction mechanisms on broad classes of materials and in a wide range of operating conditions (e.g., pH, solvent, electrolyte). Such efforts would build on current frameworks for understanding catalysis to provide the deeper insights needed to fine-tune catalyst properties in an optimal manner. The long-term goal is to continue improving the activity and selectivity of these catalysts in order to realize the prospects of using renewable energy to provide the fuels and chemicals that we need for a sustainable energy future.

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4,506 Citations

Journal ArticleDOI: 10.1021/JA3089923
Abstract: Electrochemical systems, such as fuel cell and water splitting devices, represent some of the most efficient and environmentally friendly technologies for energy conversion and storage. Electrocatalysts play key roles in the chemical processes but often limit the performance of the entire systems due to insufficient activity, lifetime, or high cost. It has been a long-standing challenge to develop efficient and durable electrocatalysts at low cost. In this Perspective, we present our recent efforts in developing strongly coupled inorganic/nanocarbon hybrid materials to improve the electrocatalytic activities and stability of inorganic metal oxides, hydroxides, sulfides, and metal–nitrogen complexes. The hybrid materials are synthesized by direct nucleation, growth, and anchoring of inorganic nanomaterials on the functional groups of oxidized nanocarbon substrates including graphene and carbon nanotubes. This approach affords strong chemical attachment and electrical coupling between the electrocatalytic n...

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757 Citations

Journal ArticleDOI: 10.1038/NNANO.2016.304
Javeed Mahmood1, Feng Li1, Sun-Min Jung1, Mahmut Sait Okyay1  +5 moreInstitutions (1)
Abstract: Ruthenium nanoparticles homogeneously dispersed in a nitrogenated, two-dimensional carbon matrix show high turnover frequency and small overpotential for hydrogen evolution reaction both in acidic and alkaline media. The hydrogen evolution reaction (HER) is a crucial step in electrochemical water splitting and demands an efficient, durable and cheap catalyst if it is to succeed in real applications1,2,3. For an energy-efficient HER, a catalyst must be able to trigger proton reduction with minimal overpotential4 and have fast kinetics5,6,7,8,9. The most efficient catalysts in acidic media are platinum-based, as the strength of the Pt–H bond10 is associated with the fastest reaction rate for the HER11,12. The use of platinum, however, raises issues linked to cost and stability in non-acidic media. Recently, non-precious-metal-based catalysts have been reported, but these are susceptible to acid corrosion and are typically much inferior to Pt-based catalysts, exhibiting higher overpotentials and lower stability13,14,15. As a cheaper alternative to platinum, ruthenium possesses a similar bond strength with hydrogen (∼65 kcal mol–1)16, but has never been studied as a viable alternative for a HER catalyst. Here, we report a Ru-based catalyst for the HER that can operate both in acidic and alkaline media. Our catalyst is made of Ru nanoparticles dispersed within a nitrogenated holey two-dimensional carbon structure (Ru@C2N). The Ru@C2N electrocatalyst exhibits high turnover frequencies at 25 mV (0.67 H2 s−1 in 0.5 M H2SO4 solution; 0.75 H2 s−1 in 1.0 M KOH solution) and small overpotentials at 10 mA cm–2 (13.5 mV in 0.5 M H2SO4 solution; 17.0 mV in 1.0 M KOH solution) as well as superior stability in both acidic and alkaline media. These performances are comparable to, or even better than, the Pt/C catalyst for the HER.

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Topics: Catalyst support (64%), Electrocatalyst (60%), Catalysis (56.99%) ... show more

733 Citations