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

A review on g-C3N4-based photocatalysts

Ongoing technological advances in diverse fields including portable electronics, transportation, and green energy are often hindered by the insufficient capability of energy-storage devices By taking advantage of two different electrode materials, asymmetric supercapacitors can extend their operating voltage window beyond the thermodynamic decomposition voltage of electrolytes while enabling a solution to the energy storage limitations of symmetric supercapacitors This review provides comprehensive knowledge to this field We first look at the essential energy-storage mechanisms and performance evaluation criteria for asymmetric supercapacitors to understand the wide-ranging research conducted in this area Then we move to the recent progress made for the design and fabrication of electrode materials and the overall structure of asymmetric supercapacitors in different categories We also highlight several key scientific challenges and present our perspectives on enhancing the electrochemical performance of future asymmetric supercapacitors

Design and Mechanisms of Asymmetric Supercapacitors.

The construction of highly active and stable non-noble-metal electrocatalysts for hydrogen and oxygen evolution reactions is a major challenge for overall water splitting. Herein, we report a novel hybrid nanostructure with CoP nanoparticles (NPs) embedded in a N-doped carbon nanotube hollow polyhedron (NCNHP) through a pyrolysis–oxidation–phosphidation strategy derived from core–shell ZIF-8@ZIF-67. Benefiting from the synergistic effects between highly active CoP NPs and NCNHP, the CoP/NCNHP hybrid exhibited outstanding bifunctional electrocatalytic performances. When the CoP/NCNHP was employed as both the anode and cathode for overall water splitting, a potential as low as 1.64 V was needed to achieve the current density of 10 mA·cm–2, and it still exhibited superior activity after continuously working for 36 h with nearly negligible decay in potential. Density functional theory calculations indicated that the electron transfer from NCNHP to CoP could increase the electronic states of the Co d-orbital a...

Core–Shell ZIF-8@ZIF-67-Derived CoP Nanoparticle-Embedded N-Doped Carbon Nanotube Hollow Polyhedron for Efficient Overall Water Splitting

Hydrogen fuel is considered as the cleanest renewable resource and the primary alternative to fossil fuels for future energy supply. Sustainable hydrogen generation is the major prerequisite to realize future hydrogen economy. The electrocatalytic hydrogen evolution reaction (HER), as the vital step of water electrolysis to H2 production, has been the subject of extensive study over the past decades. In this comprehensive review, we first summarize the fundamentals of HER and review the recent state-of-the-art advances in the low-cost and high-performance catalysts based on noble and non-noble metals, as well as metal-free HER electrocatalysts. We systemically discuss the insights into the relationship among the catalytic activity, morphology, structure, composition, and synthetic method. Strategies for developing an effective catalyst, including increasing the intrinsic activity of active sites and/or increasing the number of active sites, are summarized and highlighted. Finally, the challenges, perspectives, and research directions of HER electrocatalysis are featured.

Recent Advances in Electrocatalytic Hydrogen Evolution Using Nanoparticles.

Rational design and exploration of robust and low-cost bifunctional oxygen reduction/evolution electrocatalysts are greatly desired for metal–air batteries. Herein, a novel high-performance oxygen electrode catalyst is developed based on bimetal FeCo nanoparticles encapsulated in in situ grown nitrogen-doped graphitic carbon nanotubes with bamboo-like structure. The obtained catalyst exhibits a positive half-wave potential of 0.92 V (vs the reversible hydrogen electrode, RHE) for oxygen reduction reaction, and a low operating potential of 1.73 V to achieve a 10 mA cm−2 current density for oxygen evolution reaction. The reversible oxygen electrode index is 0.81 V, surpassing that of most highly active bifunctional catalysts reported to date. By combining experimental and simulation studies, a strong synergetic coupling between FeCo alloy and N-doped carbon nanotubes is proposed in producing a favorable local coordination environment and electronic structure, which affords the pyridinic N-rich catalyst surface promoting the reversible oxygen reactions. Impressively, the assembled zinc–air batteries using liquid electrolytes and the all-solid-state batteries with the synthesized bifunctional catalyst as the air electrode demonstrate superior charging–discharging performance, long lifetime, and high flexibility, holding great potential in practical implementation of new-generation powerful rechargeable batteries with portable or even wearable characteristic.

Atomic Modulation of FeCo–Nitrogen–Carbon Bifunctional Oxygen Electrodes for Rechargeable and Flexible All-Solid-State Zinc–Air Battery

ZnCo2 O4 quantum dots anchored on nitrogen-doped carbon nanotubes (N-CNT) retain the high catalytic activity of ZnCo2 O4 to oxidize water while enabling an efficient oxygen reduction performance thereby combining these desirable features. These advantages realize a bifunctional catalytic activity for ZnCo2 O4 /N-CNT that can be used in rechargeable zinc-air batteries.

ZnCo2 O4 Quantum Dots Anchored on Nitrogen-Doped Carbon Nanotubes as Reversible Oxygen Reduction/Evolution Electrocatalysts.

Herein, we demonstrate the use of heterostructures comprised of Co/β-Mo2 C@N-CNT hybrids for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in an alkaline electrolyte. The Co can not only create a well-defined heterointerface with β-Mo2 C but also overcomes the poor OER activity of β-Mo2 C, thus leading to enhanced electrocatalytic activity for HER and OER. DFT calculations further proved that cooperation between the N-CNTs, Co, and β-Mo2 C results in lower energy barriers of intermediates and thus greatly enhances the HER and OER performance. This study not only provides a simple strategy for the construction of heterostructures with nonprecious metals, but also provides in-depth insight into the HER and OER mechanism in alkaline solution.

Heterostructures Composed of N‑Doped Carbon Nanotubes Encapsulating Cobalt and β‑Mo 2 C Nanoparticles as Bifunctional Electrodes for Water Splitting

A complex hydroxide/metal Ni(OH)2@Ni core–shell electrode was developed for a high-performance and flexible pseudocapacitor. Compared to the conventional Ni(OH)2 electrode, the as-prepared amorphous Ni(OH)2@ three-dimensional (3D) Ni core–shell electrode shows a large specific capacitance of 2868 F g−1 at a scan rate of 1 mV s−1 and a good cycling stability (3% degradation after 1000 cycles) at a scan rate of 100 mV s−1. Furthermore, the high rate capability with a specific capacitance of 2454 F g−1 can be achieved at a charge–discharge current density of 5 A g−1. An amorphous Ni(OH)2@3D Ni-AC based asymmetric supercapacitor could be cycled reversibly in the high-voltage region of 0–1.3 V, and the specific capacitance of 92.8 F g−1 at 1 A g−1. This research demonstrates that introduction of a metal core to conventional hydroxide supercapacitor electrodes could open up new opportunities for designing and developing high-performance supercapacitors.

Amorphous Ni(OH)2 @ three-dimensional Ni core–shell nanostructures for high capacitance pseudocapacitors and asymmetric supercapacitors

The design and synthesis of robust and efficient photocatalysts for water splitting to generate hydrogen is deemed to be a promising approach for sustainable energy sources. In this work, noble-metal-free nanostructured ternary NiS/CDs/CdS (NCCS) photocatalysts were elaborately designed and successfully synthesized for high-efficient hydrogen evolution. Taking the advantages of strong absorption and electron buffer property of carbon dots (CDs), as well as merits of internal p-n junction formed between NiS and CdS, the as-prepared NCCS composite shows prominent promotion of hydrogen evolution in comparison with single CdS photocatalyst and binary hybrids (NiS/CdS and CDs/CdS). Remarkably, the optimal ternary hybrid achieves a hydrogen production rate as high as 1444.5 μmol h−1 g−1 under visible light irradiation (λ > 420 nm), up to 5.38 times over bare CdS spheres. This work paves a new pathway for the rational design of efficient hybrid photocatalysts toward solar energy conversion to chemical fuels.

Zhao-Qing Liu

Papers

Atomic Modulation of FeCo–Nitrogen–Carbon Bifunctional Oxygen Electrodes for Rechargeable and Flexible All-Solid-State Zinc–Air Battery

ZnCo2 O4 Quantum Dots Anchored on Nitrogen-Doped Carbon Nanotubes as Reversible Oxygen Reduction/Evolution Electrocatalysts.

Heterostructures Composed of N‑Doped Carbon Nanotubes Encapsulating Cobalt and β‑Mo 2 C Nanoparticles as Bifunctional Electrodes for Water Splitting

Amorphous Ni(OH)2 @ three-dimensional Ni core–shell nanostructures for high capacitance pseudocapacitors and asymmetric supercapacitors

Dual-cocatalysts decorated rimous CdS spheres advancing highly-efficient visible-light photocatalytic hydrogen production