Ruthenium single atoms implanted continuous MoS2-Mo2C heterostructure for high-performance and stable water splitting

Merging metal single atoms into a nanostructure is a novel approach to motivate the number and types of active centers for boosting catalytic activities towards both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in water splitting. Herein, we reported a continuous molybdenum sulfide-carbide heterostructure-based nanosheets incorporated with ruthenium atoms (2.02 at%) and shelled over high-conductive 1D titanium nitride nanorod arrays (Ru-MoS2-Mo2C/TiN) to form a 3D hierarchical porous material via an effective synthesis strategy. The material with fine-tuned electronic structure and multi-integrated active sites exhibited small overpotentials of 25 and 280 mV at 10 mA cm(-2) for HER and OER in 1.0 M KOH medium, respectively. An electrolyzer delivered from Ru-MoS2-Mo2C/TiN required an operating voltage of only 1.49 V at 10 mA cm(-2), surpassing that of a commercial catalyst-based system as well as earlier reports. The good performance was identified by its enlarged electroactive surface area and superior charge-transfer ability. In addition, theoretical calculations further showed its reasonable density of states near the Fermi level together with optimum adsorption free energy for reactants. The result indicated that the Ru-MoS2-Mo2C/TiN on CC is an excellent bifunctional electrocatalyst for hydrogen production by electrochemical water splitting

Trimetallic Oxide Electrocatalyst for Enhanced Redox Activity in Zinc–Air Batteries Evaluated by In Situ Analysis

Abstract Researchers are investigating innovative composite materials for renewable energy and energy storage systems. The major goals of this studies are i) to develop a low‐cost and stable trimetallic oxide catalyst and ii) to change the electrical environment of the active sites through site‐selective Mo substitution. The effect of Mo on NiCoMoO4 is elucidated using both in situ X‐ray absorption spectroscopy and X‐ray diffraction analysis. Also, density functional theory strategies show that NiCoMoO4 has extraordinary catalytic redox activity because of the high adsorption energy of the Mo atom on the active crystal plane. Further, it is demonstrated that hierarchical nanoflower structures of NiCoMoO4 on reduced graphene oxide can be employed as a powerful bifunctional electrocatalyst for oxygen reduction/evolution reactions in alkaline solutions, providing a small overpotential difference of 0.75 V. Also, Zn–air batteries based on the developed bifunctional electrocatalyst exhibit outstanding cycling stability and a high‐power density of 125.1 mW cm−2. This work encourages the use of Zn–air batteries in practical applications and provides an interesting concept for designing a bifunctional electrocatalyst