Electrochemical water splitting represents one of the most promising technologies to produce green hydrogen, which can help to realize the goal of achieving carbon neutrality. While substantial efforts on a laboratory scale have been made for understanding fundamental catalysis and developing high-performance electrocatalysts for the two half-reactions involved in water electrocatalysis, much less attention has been paid to doing relevant research on a larger scale. For example, few such researches have been done on an industrial scale. Herein, we review the very recent endeavors to bridge the gaps between fundamental research and industrial applications for water electrolysis. We begin by introducing the fundamentals of electrochemical water splitting and then present comparisons of testing protocol, figure of merit, catalyst of interest, and manufacturing cost for laboratory and industry-based water-electrolysis research. Special attention is paid to tracking the surface reconstruction process and identifying real catalytic species under different testing conditions, which highlight the significant distinctions of corresponding electrochemical reconstruction mechanisms. Advances in catalyst designs for industry-relevant water electrolysis are also summarized, which reveal the progress of moving the practical applications forward and accelerating synergies between material science and engineering. Perspectives and challenges of electrocatalyst design strategies are proposed finally to further bridge the gaps between lab-scale research and large-scale electrocatalysis applications. 

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/eem2.12441

Electrochemical Water Splitting: Bridging the Gaps between Fundamental Research and Industrial Applications

At the initial stage of the oxygen evolution reaction (OER) most electrocatalysts undergo structural and chemical surface reconstruction. While this reconstruction strongly influences their performance, it is frequently overlooked. Herein, we analyze the role of the oxidized anions, which is particularly neglected in most previous works. We introduce a range of different anionic groups (Cl-, CH3COO-, NO3-, SO42-) on the surface of an amorphous ZnCoxNiyOz catalyst by a facile proton etching and ion exchange method from a ZIF-8 self-sacrificial template. The structural and chemical properties of the obtained set of materials are thoroughly analysed and correlated with their electrocatalytic performance to study the effect of surface anionic groups, phase transition, metal leaching and defect generation on OER activity. Exploiting the control possibilities provided by the synthesis method here described and employing the uncovered property-performance correlations, the electrocatalyst is optimized. As a result, we produce ZnCo1.25Ni0.73Ox-SO4 catalysts with outstanding OER performances, including a low overpotential of 252 mV at 10 mA cm−2 with a small Tafel slope of 41.6 mV dec−1. Furthermore, this catalyst exhibits remarkable stability with negligible overpotential variation for 100 h. The excellent catalytic properties are rationalized using density functional theory calculations, showing that the surface-adsorbed anions, particularly SO42−, can stabilize the OOH* intermediate, thus enhancing the OER activity. This work oﬀers new insight into the roles of metal leaching and surface-adsorbed anions in the OER progress and facilitates the rational design of highly-efficient electrocatalysts for OER. 

Unveiling the Role of Counter-Anions in Amorphous Transition Metal-Based Oxygen Evolution Electrocatalysts

Corner‐sharing and edge‐sharing networks are the two most important material genomes. Inspired by the efficient electron transport capacity of corner‐sharing structures and the low steric hindrance of edge‐sharing units, an attempt is made to exert both merits by combining these two networks. Here, a unique self‐assembled hybrid SrCo0.55Fe0.5O3‐δ nanorod composed of a corner‐sharing SrCo0.5Fe0.5O3‐δ phase and edge‐sharing Co3O4 structure is synthesized through a Co‐site enrichment method, which exhibits the low overpotentials of 310 and 290 mV at 10 mA cm–2 for oxygen‐evolving reaction in 0.1 m and 1.0 m KOH, respectively. This efficiency is attributed to the high Co valence with strong CoO covalence and the short distance between CoCo/Fe metal active sites in hybrid nanorods, realizing a synergistic benefit. Combined multiple operando/ex situ characterizations and computational studies show that the edge‐sharing units in hybrid nanorods can help facilitate the deprotonation step of lattice oxygen mechanism (LOM) while the corner‐sharing motifs can accelerate the electron transport during LOM processes, triggering an unusual lattice‐oxygen activation. This methodology of combining important material structural genomes can offer meaningful insights and guidance for various catalytic applications.

Combined Corner‐Sharing and Edge‐Sharing Networks in Hybrid Nanocomposite with Unusual Lattice‐Oxygen Activation for Efficient Water Oxidation

Simultaneously mastering operando strain and reconstruction effects via phase-segregation strategy for enhanced oxygen-evolving electrocatalysis

Copper foam-derived electrodes as efficient electrocatalysts for conventional and hybrid water electrolysis

Exploring effective, facile, and universal tuning strategies to optimize material physicochemical properties and catalysis processes is critical for many sustainable energy systems, but still challenging. Herein, we succeed to introduce tensile strain into various perovskites via a facile thermochemical reduction method, which can greatly improve material performance for the bottleneck oxygen-evolving reaction in water electrolysis. As an ideal proof-of-concept, such a chemical-induced tensile strain turns hydrophobic Ba5Co4.17Fe0.83O14- δ perovskite into the hydrophilic one by modulating its solid–liquid tension, contributing to its beneficial adsorption of important hydroxyl reactants as evidenced by fast operando spectroscopy. Both surface-sensitive and bulk-sensitive absorption spectra show that this strategy introduces oxygen vacancies into the saturated face-sharing Co-O motifs of Ba5Co4.17Fe0.83O14- δ and transforms such local structures into the unsaturated edge-sharing units with positive charges and enlarged electrochemical active areas, creating a molecular-level hydroxyl pool. Theoretical computations reveal that this strategy well reduces the thermodynamic energy barrier for hydroxyl adsorption, lowers the electronic work function, and optimizes the charge/electrostatic potential distribution to facilitate the electron transport between active sites and hydroxyl reactants. Also, this strategy is reliable for other single, double, and Ruddlesden–Popper perovskites. We believe that this finding will enlighten rational material design and in-depth understanding for many potential applications.

http://ira.lib.polyu.edu.hk/bitstream/10397/94167/1/Guan_Chemical-induced_Tensile_Strain.pdf

A universal chemical-induced tensile strain tuning strategy to boost oxygen-evolving electrocatalysis on perovskite oxides

Correlation between interfacial layer properties and physical stability of food emulsions: current trends, challenges, strategies, and further perspectives.

Jian Zhong

Papers

A universal chemical-induced tensile strain tuning strategy to boost oxygen-evolving electrocatalysis on perovskite oxides

Correlation between interfacial layer properties and physical stability of food emulsions: current trends, challenges, strategies, and further perspectives.

Size-effect on Ni electrocatalyst: The case of electrochemical benzyl alcohol oxidation