다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Replacing precious platinum with earth-abundant materials for the oxygen reduction reaction (ORR) in fuel cells has been the objective worldwide for several decades. In the last 10 years, the fastest-growing branch in this area has been carbon-based metal-free ORR electrocatalysts. Great progress has been made in promoting the performance and understanding the underlying fundamentals. Here, a comprehensive review of this field is presented by emphasizing the emerging issues including the predictive design and controllable construction of porous structures and doping configurations, mechanistic understanding from the model catalysts, integrated experimental and theoretical studies, and performance evaluation in full cells. Centering on these topics, the most up-to-date results are presented, along with remarks and perspectives for the future development of carbon-based metal-free ORR electrocatalysts.

Carbon-Based Metal-Free ORR Electrocatalysts for Fuel Cells: Past, Present, and Future.

Insight into the design of defect electrocatalysts: From electronic structure to adsorption energy

Urea oxidation reaction (UOR) is the underlying reaction that determines the performance of modern urea-based energy conversion technologies. These technologies include electrocatalytic and photoelectrochemical urea splitting for hydrogen production and direct urea fuel cells as power engines. They have demonstrated great potentials as alternatives to current water splitting and hydrogen fuel cell systems with more favorable operating conditions and cost effectiveness. At the moment, UOR performance is mainly limited by the 6-electron transfer process. In this case, various material design and synthesis strategies have recently been reported to produce highly efficient UOR catalysts. The performance of these advanced catalysts is optimized by the modification of their structural and chemical properties, including porosity development, heterostructure construction, defect engineering, surface functionalization, and electronic structure modulation. Considering the rich progress in this field, the recent advances in the design and synthesis of UOR catalysts for urea electrolysis, photoelectrochemical urea splitting, and direct urea fuel cells are reviewed here. Particular attention is paid to those design concepts, which specifically target the characteristics of urea molecules. Moreover, challenges and prospects for the future development of urea-based energy conversion technologies and corresponding catalysts are also discussed.

Designing Advanced Catalysts for Energy Conversion Based on Urea Oxidation Reaction.

Exploring Indium-Based Ternary Thiospinel as Conceivable High-Potential Air-Cathode for Rechargeable Zn–Air Batteries

It is an urgent requirement to develop non-precious metal-based catalysts with excellent electrocatalytic activity and stability to accelerate the development of hydrogen generation via energy-efficient routes. Herein, a facile and scalable strategy was developed to synthesize both rod-like Co(OH)F and Co–P nanoarrays supported on Ni-foam, denoted as Co(OH)F/NF and Co–P/NF, respectively. Electrochemical measurements demonstrate that Co–P/NF exhibits excellent electrocatalytic performance for the hydrogen evolution reaction (HER), delivering a low overpotential of 70 mV and 43 mV at 10 mA cm−2 in alkaline and acid media, respectively. Furthermore, the as-prepared Co(OH)F/NF contributes to an outstanding oxygen evolution reaction (OER) performance with a low oxidation potential of about 1.5 V at 10 mA cm−2. In addition, the Co(OH)F/NF also can enable highly efficient urea oxidation reaction (UOR) electrocatalysis, which can be utilized to substitute OER to lower the overpotential and thus reduce electrical energy consumption during H2-production. As a proof of concept, full water-splitting measurements were performed with Co–P/NF and Co(OH)F/NF as cathode and anode, respectively, in 1 M KOH with 0.7 M urea. The Co–P/NF‖Co(OH)F/NF electrode is capable of producing a current density of 20 mA cm−2 at a cell potential of only 1.42 V, which is 230 mV less than that for the urea-free counterpart, demonstrating its potential feasibility in practical applications of energy-efficient hydrogen production.

Ni-foam supported Co(OH)F and Co–P nanoarrays for energy-efficient hydrogen production via urea electrolysis

Design of cost-effective bifunctional electrocatalysts for both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is vital for developing hydrogen energy for the future. Herein, a cost-effective phosphorus-doped Co–Fe–B material with chain-like structure (denoted as Co1–Fe1–B–P) is reported as an efficient and novel bifunctional electrocatalyst for the OER and HER, and was produced via a facile water-bath synthesis and subsequent phosphorization. For the OER, the as-prepared Co1–Fe1–B–P nanochains require an extremely low overpotential of about 225 mV at 10 mA cm−2 and possess a small Tafel slope of 40 mV dec−1 in alkaline media. Impressively, the HER properties of Co1–Fe1–B–P nanochains are superior to those of P-free Co–Fe–B in terms of overpotential at 10 mA cm−2 (173 mV vs. 239 mV) and kinetic Tafel slope (96 mV dec−1vs. 105 mV dec−1). The synergetic effect between Co–Fe–B and doped-P is mainly responsible for the satisfactory bifunctional performance, while the one-dimensional (1D) chain-like structure endows Co1–Fe1–B–P with abundant catalytically active sites that enhance the atom utilization efficiency. Moreover, the developed Co1–Fe1–B–P nanochains can be simultaneously utilized as both the cathode and anode for overall water-splitting, which requires a cell voltage of only 1.68 V to deliver 10 mA cm−2. This work provides a feasible and promising protocol to realize metal borides as efficient electrocatalysts in energy-related applications.

Facile synthesis of Co-Fe-B-P nanochains as an efficient bifunctional electrocatalyst for overall water-splitting.

Herein, nitrogen-doped carbon coated hollow Co9S8 microtubes (Co9S8@N–C microtubes) are prepared through a facile solvothermal procedure, followed by dopamine polymerization process together with a post-pyrolysis which present excellent electrocatalytic activity for oxygen reduction reaction (ORR). The Co9S8 within the hollow Co9S8@N–C microtubes presents a well-defined single-crystal structure with dominated (022) plane. To obtain desired electrocatalyst, the annealing temperature and the thickness of carbon layer tuned by changing the dopamine concentration are optimized systematically. The electrochemical results demonstrate that the coordination of the N-doped carbon layer, exposed (022) plane, and hollow architecture of Co9S8 microtubes calcined at 700 °C affords outstanding ORR performance to Co9S8@N–C microtubes. The moderate thickness of the carbon layer is crucial for improving ORR activity of Co9S8@N–C microtubes, while increasing or decreasing the thickness would result in activity decrease. Mo...

Boosting Oxygen Reduction Catalysis with N-doped Carbon Coated Co9S8 Microtubes.

Developing highly efficient and low-cost nonprecious electrocatalysts for hydrogen evolution reaction (HER) has a pivotal impact on the emergence of hydrogen energy. Herein, quaternary electrocatal...

Interface Engineering of MoS2 for Electrocatalytic Performance Optimization for Hydrogen Generation via Urea Electrolysis

Electrocatalysis for the oxygen reduction reaction (ORR) at the cathode plays a critical role in fuel cells and metal-air batteries. However, the high-cost and sluggish kinetics of the catalytic reaction have hindered its development. Therefore, developing efficient catalysts to address these issues is of vital significance. In this work, we summarized the recent progress of nitrogen (N)-doped metal-free catalysts for the ORR, owing to their high catalytic activity (comparable to Pt/C) and cost-effectiveness. The synthetic strategy and the morphology structure to catalytic performance are mainly discussed. Furthermore, the design of N-doped nanomaterials with other heteroatoms in aiming to further enhance the ORR performance is also reviewed. At the end of the review, we provide a brief summary of the N-doped carbon-based catalysts in enhancing the ORR performance and give future perspectives for their further development.

Min Song

Papers

Ni-foam supported Co(OH)F and Co–P nanoarrays for energy-efficient hydrogen production via urea electrolysis

Facile synthesis of Co-Fe-B-P nanochains as an efficient bifunctional electrocatalyst for overall water-splitting.

Boosting Oxygen Reduction Catalysis with N-doped Carbon Coated Co9S8 Microtubes.

Interface Engineering of MoS2 for Electrocatalytic Performance Optimization for Hydrogen Generation via Urea Electrolysis

Recent Progress in Nitrogen-Doped Metal-Free Electrocatalysts for Oxygen Reduction Reaction