In Situ Engineering Multifunctional Active Sites of Ruthenium-Nickel Alloys for pH-Universal Ampere-Level Current-Density Hydrogen Evolution

Developing robust non-platinum electrocatalysts with multifunctional active sites for pH-universal hydrogen evolution reaction (HER) is crucial for scalable hydrogen production through electrochemical water splitting. Here ultra-small ruthenium-nickel alloy nanoparticles steadily anchored on reduced graphene oxide papers (Ru-Ni/rGOPs) as versatile electrocatalytic materials for acidic and alkaline HER are reported. These Ru-Ni alloy nanoparticles serve as pH self-adaptive electroactive species by making use of in situ surface reconstruction, where surface Ni atoms are hydroxylated to produce bifunctional active sites of Ru-Ni(OH)2 for alkaline HER, and selectively etched to form monometallic Ru active sites for acidic HER, respectively. Owing to the presence of Ru-Ni(OH)2 multi-site surface, which not only accelerates water dissociation to generate reactive hydrogen intermediates but also facilitates their recombination into hydrogen molecules, the self-supported Ru90Ni10/rGOP hybrid electrode only takes overpotential of as low as ≈106 mV to deliver current density of 1000 mA cm-2, and maintains exceptional stability for over 1000 h in 1 m KOH. While in 0.5 m H2SO4, the Ru90Ni10/rGOP hybrid electrode exhibits acidic HER catalytic behavior comparable to commercially available Pt/C catalyst due to the formation of monometallic Ru shell. These electrochemical behaviors outperform some of the best Ru-based catalysts and make it attractive alternative to Pt-based catalysts toward highly efficient HER.

Lamella-heterostructured nanoporous bimetallic iron-cobalt alloy/oxyhydroxide and cerium oxynitride electrodes as stable catalysts for oxygen evolution

Developing robust nonprecious-metal electrocatalysts with high activity towards sluggish oxygen-evolution reaction is paramount for large-scale hydrogen production via electrochemical water splitting. Here we report that self-supported laminate composite electrodes composed of alternating nanoporous bimetallic iron-cobalt alloy/oxyhydroxide and cerium oxynitride (FeCo/CeO_2-xN_x) heterolamellas hold great promise as highly efficient electrocatalysts for alkaline oxygen-evolution reaction. By virtue of three-dimensional nanoporous architecture to offer abundant and accessible electroactive CoFeOOH/CeO_2-xN_x heterostructure interfaces through facilitating electron transfer and mass transport, nanoporous FeCo/CeO_2-xN_x composite electrodes exhibit superior oxygen-evolution electrocatalysis in 1 M KOH, with ultralow Tafel slope of ~33 mV dec^-1. At overpotential of as low as 360 mV, they reach >3900 mA cm^-2 and retain exceptional stability at ~1900 mA cm^-2 for >1000 h, outperforming commercial RuO₂ and some representative oxygen-evolution-reaction catalysts recently reported. These electrochemical properties make them attractive candidates as oxygen-evolution-reaction electrocatalysts in electrolysis of water for large-scale hydrogen generation.

Surface-Alloyed Nanoporous Zinc as Reversible and Stable Anodes for High-Performance Aqueous Zinc-Ion Battery

Metallic zinc (Zn) is one of the most attractive multivalent-metal anode materials in post-lithium batteries because of its high abundance, low cost and high theoretical capacity. However, it usually suffers from large voltage polarization, low Coulombic efficiency and high propensity for dendritic failure during Zn stripping/plating, hindering the practical application in aqueous rechargeable zinc-metal batteries (AR-ZMBs). Here we demonstrate that anionic surfactant-assisted in situ surface alloying of Cu and Zn remarkably improves Zn reversibility of 3D nanoporous Zn electrodes for potential use as high-performance AR-ZMB anode materials. As a result of the zincophilic Zn_xCu_y alloy shell guiding uniform Zn deposition with a zero nucleation overpotential and facilitating Zn stripping via the Zn_xCu_y/Zn galvanic couples, the self-supported nanoporous Zn_xCu_y/Zn electrodes exhibit superior dendrite-free Zn stripping/plating behaviors in ambient aqueous electrolyte, with ultralow polarizations under current densities up to 50 mA cm^‒2, exceptional stability for 1900 h and high Zn utilization. This enables AR-ZMB full cells constructed with nanoporous Zn_xCu_y/Zn anode and K_zMnO₂ cathode to achieve specific energy of as high as ~ 430 Wh kg^‒1 with ~ 99.8% Coulombic efficiency, and retain ~ 86% after long-term cycles for > 700 h.

Nanoporous Intermetallic Cu3 Sn/Cu Hybrid Electrodes as Efficient Electrocatalysts for Carbon Dioxide Reduction

Designing highly selective and cost-effective electrocatalysts toward electrochemical carbon dioxide (CO₂ ) reduction is crucial for desirable transformation of greenhouse gas into fuels or high-value chemical products. Here, the authors report intermetallic Cu₃ Sn that is in situ formed and seamlessly integrated on self-supported bimodal nanoporous Cu skeleton (Cu₃ Sn/Cu) via a spontaneous alloying of Sn and Cu as robust electrocatalyst for selective electroreduction of CO₂ to CO. By virtue of Sn atoms strengthening CO adsorption on Cu atoms, the intermetallic Cu₃ Sn has an intrinsic activity of ≈10.58 μA cm^-2 , more than 80-fold higher than that of monometallic Cu. By virtue of hierarchical bicontinuous nanoporous Cu architecture facilitating electron transfer and CO₂ and proton mass transport and offering high specific surface areas for full use of electroactive Cu₃ Sn sites, the nanoporous Cu₃ Sn/Cu hybrid electrodes produce CO at a low overpotential of 0.09 V, and exhibit high partial current density of ≈15 mA cm^-2 _geo at overpotential of 0.59 V, along with excellent stability and selectivity of 91.5% Faradaic efficiency. The outstanding electrochemical performance make them attractive alternatives to precious Au- and Ag-based electrocatalysts for building low-cost CO₂ electrolyzers to selectively produce CO.

The impact of the neonatal resuscitation program guidelines (NRPG) on the neonatal mortality in a hospital in Zhuhai, China

AIM

The neonatal resuscitation program (NRPG) was first introduced in our hospital to replace the traditional resuscitation (TR) program in 1993. TR has been in existence in China for a long time. The implementation of NRPG was timely in reducing the number of infant mortality and also to disseminate to the many hospitals in China which are still practising TR.

METHOD

A perspective study of 4,751 newborns with 366 asphyxiated babies in a period of 2 years was carried out. A previous sample of 1,722 live births under the TR program was compared as a controlled group statistically.

RESULTS

From August 1993 to August 1995, when NRPG was exclusively implemented in our hospital, only 16 newborns died within 7 days, out of 4,751 births (3.4%) with 2 deaths in the delivery room. Seventeen newborns died within 7 days out of 1,722 births (9.9+) in the TR group, with 10 deaths in the delivery room. From the data shown, it can be clearly seen that perinatal neonatal mortality rate was reduced almost 3 times after NRPG was implemented (chi(2) = 10.54, p < 0.01). The follow-up results of 21 cases of severe asphyxia at 2 months--1 year of age were normal except for one with cerebral palsy.

CONCLUSIONS

Our study showed that NRPG was indeed a very effective and feasible technique during the delivery process in the reduction of neonatal mortality. It is important to disseminate widely the knowledge and technique of NRPG in places where TR is still being widely practiced especially in developing countries.