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Electrocatalytic water splitting driven by renewable electricity has attracted great interest in recent years for producing hydrogen with high-purity. However, the practical applications of this technology are limited by the development of electrocatalysts with high activity, low cost, and long durability. In the search for new electrocatalysts, computational chemistry has made outstanding contributions by providing fundamental laws that govern the electron behavior and enabling predictions of electrocatalyst performance. This review delves into theoretical studies on electrochemical water-splitting processes. Firstly, we introduce the fundamentals of electrochemical water electrolysis and subsequently discuss the current advancements in computational methods and models for electrocatalytic water splitting. Additionally, a comprehensive overview of benchmark descriptors is provided to aid in understanding intrinsic catalytic performance for water-splitting electrocatalysts. Finally, we critically evaluate the remaining challenges within this field. [ABSTRACT FROM AUTHOR]

The overall energy efficiency of electrochemical systems is severely hindered by the traditional anodic oxygen evolution reaction (OER). Utilizing urea oxidation reaction (UOR) with lower thermodynamic potential to replace OER provides a promising strategy to enhance the energy efficiency. Amorphous and heterojunctions electrocatalysts have been aroused extensive studies owing to their unique physicochemical properties and outperformed activity. Herein, we report a simple method to construct a novel crystalline—amorphous NiO-CrOx heterojunction grown on Ni foam for UOR electrocatalyst. The NiO-CrOx electrocatalyst displays excellent UOR performance with an ultralow working potential of 1.32 V at 10 mA·cm−2 and ultra-long stability about 5 days even at 100 mA·cm−2. In-situ Raman analysis and temperature-programmed desorption (TPD) measurement verify that the presence of the amorphous CrOx phase can boost the reconstruction from NiO to active NiOOH species and enhance adsorption ability of urea molecule. Besides, the unique crystalline—amorphous interfaces are also benefit to improving the UOR performance. [ABSTRACT FROM AUTHOR]

The interfacial synergy effect caused by the space charge transfer of heterojunctions can effectively modify the catalytic activity. Herein, a composite heterojunction catalyst of CoTe 2 /CoP with moderate Gibbs free energy of hydrogen adsorption is designed based on interfacial effects driven by work function difference between CoTe 2 and CoP. As expected, CoTe 2 /CoP only needs overpotentials of 80 mV at 10 mA cm−2 and stability for continuous catalysis at the current density of 100 mA cm−2 for 20 h in hydrogen evolution reaction (HER). The experimental results and theory calculations identify that the built-in field drives the transfer of electrons from CoTe 2 to CoP at the interface, which realizes electronic redistribution with increased electron density on the Co atoms in CoP and optimizes the adsorption-free energy of the reaction intermediates, thereby, accelerating HER kinetics. Besides, the CoTe 2 /CoP heterostructure also behaves the excellent catalytic activity towards water splitting. [Display omitted] • CoTe 2 /CoP is prepared via one-step phosphotellurization method. • Built-in field drives the transfer of electrons from CoTe 2 to CoP at the interface. • Electronic redistribution optimizes the adsorption-free energy of the reaction intermediates. • CoTe 2 /CoP exhibits the boosted hydrogen evolution reaction (HER) performance. [ABSTRACT FROM AUTHOR]