Revealing the Formation Mechanism and Optimizing the Synthesis Conditions of Layered Double Hydroxides for the Oxygen Evolution Reaction

Layered double hydroxides (LDHs), whose formation is strongly related to OH⁻ concentration, have attracted significant interest in various fields. However, the effect of the real-time change of OH⁻ concentration on LDHs’ formation has not been fully explored due to the unsuitability of the existing synthesis methods for in situ characterization. Here, the deliberately designed combination of NH₃ gas diffusion and in situ pH measurement provides a solution to the above problem. The obtained results revealed the formation mechanism and also guided us to synthesize a library of LDHs with the desired attributes in water at room temperature without using any additives. After evaluating their oxygen evolution reaction performance, we found that FeNi-LDH with a Fe/Ni ratio of 25/75 exhibits one of the best performances so far reported.     

Light-driven Orderly Assembly of Ir-atomic Chains to Integrate a Dynamic Reaction Pathway for Acidic Oxygen Evolution

This work suggests an intriguing light-driven atomic assembly proposal to orderly configure the distribution of reactive sites to optimize the spin-entropy-related orbital interaction and charge transfer from electrocatalysts to intermediates. Herein, the introduced fluorine (F) atoms acting as photo-corrosion centres in MnO_1.9F_0.1 effectively soften the bonding interaction of Mn−O bonds in the IrCl₃ solution. Therefore, partial Mn atoms can be successively replaced to form orderly atomic-hybridized catalysts with a spin-related low entropy due to the coexistence of Ir-atomic chains and clusters. The time-related elemental analysis demonstrates that the dynamic dissolution/redeposition of Ir clusters in acidic oxygen evolution leads to a reintegration of the reaction pathway to seek the switchable rate-limiting step with a lower activation energy.     

Boosting Alkaline Hydrogen Evolution Reaction through Water Structure Manipulation

In the past, the design of efficient electrocatalyst materials for alkaline hydrogen evolution reaction (HER) was mostly focused on tuning the adsorption properties of reaction intermediates. A recent breakthrough shows that the performance can be improved by manipulating water structure at the electrode-electrolyte interface using atomically localized electric fields. The new approach was realized by using IrRu dizygotic single-atom sites and led to a significantly accelerated water dissociation and an overall improved alkaline HER performance. Supported by extensive data from advanced modeling, characterization, and electrochemical measurements, the work delivers an intricate examination of the interaction between water molecules and the catalyst surface, thereby enriching our understanding of water dissociation kinetics and offering new insights to boost overall alkaline HER efficiency.