Electrocatalytic oxidation of simple organic molecules offers a promising strategy to combat the sluggish kinetics of the water oxidation reaction (WOR). The low potential requirement, inhibition of the crossover of gases, and formation of value-added products at the anode are benefits of the electrocatalytic oxidation of organic molecules. Herein, we developed cobalt–nickel-based layered double hydroxide (LDH) as a robust material for the electrocatalytic oxidation of alcohols and urea at the anode, replacing the WOR. A facile synthesis protocol to form LDHs with different ratios of Co and Ni is adapted. It demonstrates that the reactants could be efficiently oxidized to concomitant chemical products at the anode. The half-cell study shows an onset potential of 1.30 V for benzyl alcohol oxidation reaction (BAOR), 1.36 V for glycerol oxidation reaction (GOR), 1.33 V for ethanol oxidation reaction (EOR), and 1.32 V for urea oxidation reaction (UOR) compared with 1.53 V for WOR. Notably, the hybrid electrolyzer in a full-cell configuration significantly reduces the overall cell voltage at a 20 mA cm–2 current density by ∼15% while coupling with the BAOR, EOR, and GOR and ∼12% with the UOR as the anodic half-cell reaction. Furthermore, the efficiency of hydrogen generation remains unhampered with the types of oxidation reactions (alcohols and urea) occurring at the anode. This work demonstrates the prospects of lowering the overall cell voltage in the case of a water electrolyzer by integrating the hydrogen evolution reaction with suitable organic molecule oxidation.

The large-scale application of water electrolysis for the generation of hydrogen can be made viable only by the development of inexpensive, robust, and bifunctional electrocatalysts. Here, we report a self-templating method for the design of porous, edge-site-rich hybrid nanomaterials via the selective etching of layered double hydroxide precursors that contain an amphoteric metal by alkali treatment, followed by vapor phase selenization. The obtained hexagonal nickel selenide nanoplates anchored over nitrogen-doped graphene showed highly efficient and robust oxygen evolution reaction (OER) electrocatalysis due to the inherent in situ electrochemical oxidation property of selenides demonstrating low overpotential of 311 mV to achieve the 10 mA cm −2 water oxidation current density in 1 M KOH. The faster reaction kinetics and long-term stability of the catalyst encouraged us to demonstrate a real alkaline water electrolyzer, which enables high-performing overall water splitting with a low overpotential of 460 mV from theoretical potential of 1.23 V to generate sufficient amounts of H 2 and O 2 by achieving a current density of 10 mA cm −2 . This study thus provides a valuable strategy to tailor the surface texture of the catalyst as well as its effectiveness in developing robust multifunctional electrocatalysts, promoting the efficient design of porous materials for catalytic applications.

Hydrogen production is vital for meeting future energy demands and managing environmental sustainability. Electrolysis of water is considered as the suitable method for H2 generation in a carbon‐free pathway. Herein, the synthesis of highly efficient Co9S8‐Ni3S2 based hierarchical nanoflower arrays on nickel foam (NF) is explored through the one‐pot hydrothermal method (Co9S8‐Ni3S2/NF) for overall water splitting applications. The nanoflower arrays are self‐supported on the NF without any binder, possessing the required porosity and structural characteristics. The obtained Co9S8‐Ni3S2/NF displays high hydrogen evolution reaction (HER), as well as oxygen evolution reaction (OER), activities in 1 m KOH solution. The overpotentials exhibited by this system at 25 mA cm−2 are nearly 277 and 102 mV for HER and OER, respectively, in 1 m KOH solution. Subsequently, the overall water splitting was performed in 1 m KOH solution by employing Co9S8‐Ni3S2/NF as both the anode and cathode, where the system required only 1.49, 1.60, and 1.69 V to deliver the current densities of 10, 25, and 50 mA cm−2, respectively. Comparison of the activity of Co9S8‐Ni3S2/NF with the state‐of‐the‐art Pt/C and RuO2 coated on NF displays an enhanced performance for Co9S8‐Ni3S2/NF both in the half‐cell as well as in the full cell, emphasizing the significance of the present work. The post analysis of the material after water electrolysis confirms that the surface Co(OH)2 formed during the course of the reaction serves as the favorable active sites. Overall, the activity modulation achieved in the present case is attributed to the presence of the open‐pore morphology of the as formed nanoflowers of Co9S8‐Ni3S2 on NF and the simultaneous presence of the surface Co(OH)2 along with the highly conducting Co9S8‐Ni3S2 core, which facilitates the adsorption of the reactants and subsequently its conversion into the gaseous products during water electrolysis.