Ni-CeO2 Heterostructure Promotes Hydrogen Evolution Reaction via Tuning of the O-H Bond Length of Adsorbed Water at the Electrolyte/Electrode Interface

Electronic Structure Modulating of W18O49 Nanospheres by Niobium Doping for Efficient Hydrogen Evolution Reaction

Hydrogen, known for its high energy density and environmental benefits, serves as a prime substitute for fossil fuels. Nonetheless, the hydrogen evolution reaction (HER), essential in electrolysis, encounters challenges with slow kinetics and significant overpotential, which elevate costs and reduce efficiency. Thus, developing efficient electrocatalysts to reduce HER overpotential is vital to enhance hydrogen production efficiency and minimize energy consumption. Adjusting the electronic structure of transition metal oxides via elemental doping is a potent strategy to improve the effectiveness of electrocatalysts for hydrogen evolution. In this work, we synthesized a set of niobium-doped tungsten oxides (Nbx-W18O49) under anoxic conditions using a straightforward "one-pot" solvothermal approach. After doping Nb, the oxygen vacancy content inside W18O49 was increased, which induced a synergistic effect with the active sites of tungsten. In acidic environments, the hydrogen evolution activity of the Nb0.6-W18O49 electrocatalyst is second only by 20 wt % Pt/C. It attains a current density of -10 mA cm-2 at an overpotential of 102 mV. By comparison with W18O49, Nb0.4-W18O49 and Nb0.5-W18O49, Nb0.6-W18O49 demonstrates a reduced charge transfer resistance, which significantly enhances its conductivity and the speed of electron movement across interfaces. Coupled with this feature are notably faster HER kinetics. Additionally, it exhibits excellent stability, meaning it maintains its performance and structural integrity over prolonged periods and under various operational conditions. This article provides a new perspective for discovering inexpensive and efficient hydrogen evolution electrocatalyst materials.

Heterointerface-Rich Ni3N/WO3 Hierarchical Nanoarrays for Efficient Glycerol Oxidation-Assisted Alkaline Hydrogen Evolution

Glycerol oxidation-assisted water electrolysis has emerged as a cost-effective way of co-producing green hydrogen and HCOOH. Still, preparing highly selective and stable nickel-based metal electrocatalysts remains a challenge. Herein, heterostructure Ni3N/WO3 nanosheet arrays of bifunctional catalysts with large specific surface areas loaded on nickel foam (denoted as Ni3N/WO3/NF) were synthesized. This catalyst was for glycerol oxidation reaction (GOR) and hydrogen evolution reaction (HER) with excellent catalytic performance, a voltage saving of 267 mV compared to oxygen evolution reaction (OER), and a HER overpotential of 104 mV at 100 mA cm-2. The cell voltage in the assembled GOR//HER hybrid electrolysis system reaches 100 mA cm-2 at 1.50 V, 296 mV lower than the potential required for overall water splitting. This work demonstrates that replacing GOR with OER using a cost-effective and highly active Ni-based bifunctional electrocatalyst can make hybrid water electrolysis an energy-efficient, sustainable, and green strategy for hydrogen production.

Rational Design of Dynamic Interface Water Evolution on Turing Electrocatalyst toward the Industrial Hydrogen Production

Manipulating the structural and kinetic dissociation processes of water at the catalyst-electrolyte interface is vital for alkaline hydrogen evolution reactions (HER) at industrial current density. This is seldom actualized due to the intricacies of the electrochemical reaction interface. Herein, this work introduces a rapid, nonequilibrium cooling technique for synthesizing ternary Turing catalysts with short-range ordered structures (denoted as FeNiRu/C). These advanced structures empower the FeNiRu/C to exhibit excellent HER performance in 1 m KOH with an ultralow overpotential of 6.5 and 166.2 mV at 10 and 1000 mA cm-2, respectively, and a specific activity 7.3 times higher than that of Pt/C. Comprehensive mechanistic analyses reveal that abundant atomic species form asymmetric atomic electric fields on the catalyst surface inducing a directed evolution and the dissociation process of interfacial H2O molecules. In addition, the locally topologized structure effectively mitigates the high hydrogen coverage of the active site induced by the high current density. The establishment of the relationship between free water population and HER activity provides a new paradigm for the design of industrially relevant high performance alkaline HER catalysts.