Carbon Dots and RuP₂ Nanohybrid as an Efficient Bifunctional Catalyst for Electrochemical Hydrogen Evolution Reaction and Hydrolysis of Ammonia Borane

Hydrogen is an ideal clean, nontoxic, and abundant energy carrier with incomparable potential development value. At present, the electrochemical hydrogen evolution reaction (HER) and the release of hydrogen from storage materials [e.g., ammonia borane (AB)] are the two most promising clean and efficient hydrogen production methods. The development of a catalyst suitable for both processes will reduce the use of resources and achieve two goals with one product. Although many catalysts have been studied to promote these reactions, unified catalysts for both reactions have rarely been reported. Reported here is the development of a novel hydrogen evolution catalyst based on a uniform self-cross-linked carbon layer loaded with ruthenium phosphide nanoparticles. A simple pyrolysis process produced a material with extraordinary catalytic activity for the HER and also outstanding activity for AB hydrolysis. The catalyst remained stable during both the reactions. This work details an innovative and feasible idea for the design and preparation of various supported catalysts

Cobalt-Ruthenium Nanoalloys Parceled in Porous Nitrogen-Doped Graphene as Highly Efficient Difunctional Catalysts for Hydrogen Evolution Reaction and Hydrolysis of Ammonia Borane

The development of clean fuels for hydrogen utilization will benefit from low-cost and active catalysts to produce hydrogen via hydrolytic dehydrogenation by electrochemical and chemical means. Herein, we designed and synthesized a high-efficiency and stable catalyst with low-ruthenium content CoRu alloy nanoparticles supported on porous nitrogen-doped graphene layers (CoRux@N-C) via pyrolysis of small organic metal molecules. The amount of ruthenium in the catalyst that showed the highest activity was only 5.07 wt %. CoRu0.25@N-C can efficiently catalyze the hydrogen evolution reaction (HER) with a wide pH range and low overpotential to drive current densities of 10 mA·cm–2 of only 27 mV (1.0 M KOH) and 94 mV (0.5 M H2SO4). CoRu0.25@N-C also showed decent durability with negligible degradation after 1000 cyclic-voltammetry cycles in both acidic and alkaline solutions. It also has excellent catalytic activity and can easily sustain ammonia borane hydrolysis with an initial turnover frequency (TOF) of 457.8 molH2 min–1 molcat–1 under ambient conditions. CoRu0.25@N-C can readily perform both NH3­BH3 hydrolytic dehydrogenation and electrochemical hydrogen evolution as a result of its highly specific surface area, carbon layer protection, metal vacancies, and a porous carbon matrix doped with heteroatoms. The creation of a multifunctional composite/hybrid by the use of small metal organic molecules can lead to cost-effective and highly efficient catalysts for energy conversion

RuO₂–CeO₂ Lattice Matching Strategy Enables Robust Water Oxidation Electrocatalysis in Acidic Media via Two Distinct Oxygen Evolution Mechanisms

The discovery of acid-stable and highly active electrocatalysts for the oxygen evolution reaction (OER) is crucial in the quest for high-performance water-splitting technologies. Herein, a heterostructured RuO2–CeO2 electrocatalyst was constructed by using a lattice-matching strategy. The interfacial Ru–O–Ce bridge structure provided a channel for electron transfer between Ru and Ce, creating a lattice stress that distorts the local structure of RuO2. The resulting RuO2–CeO2 catalyst exhibited attractive stability with negligible decay after 1000 h of the OER in 0.5 M H2SO4, along with high activity with an overpotential of only 180 mV at 10 mA cm–2. In situ attenuated total reflectance surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS), in situ differential electrochemical mass spectrometry (DEMS), and density functional theory (DFT) calculations were used to reveal that the interface and noninterface RuO2 sites enabled an oxide path mechanism (OPM) and the enhanced adsorbate evolution mechanism (AEM-plus), respectively, during the OER. The simultaneous and independent OER pathways accessible by lattice matching guides improved electrocatalyst design for the OER in acidic media

A Robust Anti-Thermal-Quenching Phosphor Based on Zero-Dimensional Metal Halide Rb₃InCl₆:<i>x</i>Sb³⁺

High-power phosphor-converted white light-emitting diodes (hp-WLEDs) have been widely involved in modern society as outdoor lighting sources. In these devices, due to the Joule effect, the high applied currents cause high operation temperatures (>500 K). Under these conditions, most phosphors lose their emission, an effect known as thermal quenching (TQ). Here, we introduce a zero-dimensional (0D) metal halide, Rb3InCl6:xSb3+, as a suitable anti-TQ phosphor offering robust anti-TQ behavior up to 500 K. We ascribe this behavior of the metal halide to two factors: (1) a compensation process via thermally activated energy transfer from structural defects to emissive centers and (2) an intrinsic structural rigidity of the isolated octahedra in the 0D structure. The anti-TQ phosphor-based WLEDs can stably work at a current of 2000 mA. The low synthesis cost and nontoxic composition reported here can herald a new generation of anti-TQ phosphors for hp-WLED