Rational regulation of electrochemical reconfiguration and exploration of activity origin are important foundations for realizing the optimization of electrocatalyst activity, but rather challenging. Herein, we potentially develop a rapid complete reconfiguration strategy for the heterostructures of CoC2O4 coated by MXene nanosheets (CoC2O4@MXene) during the hydrogen evolution reaction (HER) process. The self-assembled CoC2O4@MXene nanotubular structure has high electronic accessibility and abundant electrolyte diffusion channels, which favor the rapid complete reconfiguration. Such rapid reconfiguration creates new actual catalytic active species of Co(OH)2 transformed from CoC2O4, which is coupled with MXene to facilitate charge transfer and decrease the free energy of the Volmer step toward fast HER kinetics. The reconfigured components require low overpotentials of 28 and 216 mV at 10 and 1000 mA cm−2 in alkaline conditions and decent activity and stability in natural seawater. This work gives new insights for understanding the actual active species formation during HER and opens up a new way toward high-performance electrocatalysts.

carbon-intensive fuels. Hydrogen represents a versatile fuel with high energy density and low carbon emission. In 2020, the global hydrogen generation market size was valued at ≈120 billion USD and is expected to rapidly expand. Presently, industrial hydrogen is primarily acquired from natural gas reforming that involves energy-consuming processes with extensive greenhouse gas release. Alternatively, electrochemical water splitting is a sustainable technique to store the intermittent electricity and produce high-purity hydrogen under ambient condition. [1] The water-splitting process consists of anodic oxygen evolution reaction (OER) and cathodic hydrogen evolution reaction (HER), in which electrocatalysts are particularly vital to lower their energy barriers and reduce the required overpotentials. [2] Currently, precious metal (e.g., Pt) and metal oxides (e.g., RuO 2 , and IrO 2 ) hold the benchmark performance toward HER and OER, respectively. [3] However, their nature scarcity and high cost considerably impede their widespread utilization. Therefore, it is desirable to develop costeffective OER/HER catalysts with active, abundant, and robust surface reactive sites. Non-precious transition metal-based materials, such as oxides, [4] sulfides, [5] LDHs, [6] MOFs, [7] and their composites, [8] have received intensive research in water splitting due to their tunable structure, stability, as well as high reserve. Strategies including morphology and components tuning are applied for advanced electrocatalysts. High material surface area and porosity benefit the intermediate accessibility and fast mass transport during the electrochemical reactions. Researchers pursuit improved electrocatalysis by fabricating porous or hierarchical catalysts with highly exposed reactive sites. [9] However, the synthesis of the highly porous transition metal catalysts with the controlled crystalline phase using the traditional template strategy often needs tedious and timeconsuming manufacturing. In addition, regarding the required bifunctionality (i.e., OER and HER) for water splitting, the integration of different nanostructures by heterostructure fabrication is adopted for further optimizing the electrocatalytic performance. The interface engineering and electronic regulation facilitate the optimized chemisorption of the reaction Developing efficient bifunctional electrocatalysts toward oxygen/hydrogen evolution reactions is crucial for electrochemical water splitting toward hydrogen production. The high-performance electrocatalysts depend on the catalytically active and highly accessible reaction sites and their structural robustness, while the rational design of such electrocatalysts with desired features avoiding tedious manufacture is still challenging. Here, a facile method is reported to synthesize mesoporous and heterostructured transition metal oxides strongly anchored on a nickel skeleton (MH-TMO) containing identified Fe-Cu oxide interfaces with high intrinsic activity, easy accessibility for reaction intermediates, ...

Canadian Institutes of Health Research and Italian Ministry of Universities and Research.

Transportation infrastructure has an enormous impact on sustainable development. To identify multiple impacts of transportation infrastructure and show emerging trends and challenges, this paper presents a scientometric review based on 2543 published articles from 2000 to 2017 through co-author, co-occurring and co-citation analysis. In addition, the hierarchy of key concepts was analyzed to show emerging research objects, methods and levels according to the clustering information, which includes title, keyword and abstract. The results expressed by visual graphs compared high-impact authors, collaborative relationships among institutions in developed and developing countries. In addition, representative research issues related to the economy, society and environment were identified such as cost overrun, spatial economy, prioritizing structure, local development and land value. Additionally, two future directions, integrated research of various effects and structure analysis of transportation network, are recommended. The findings of this study provide researchers and practitioners with an in-depth understanding of transportation infrastructure’s impacts on sustainable development by visual expression.

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