Single-atom catalysts (SACs) have enormous significance in heterogeneous catalysis. However, understanding how SACs function at the molecular level remains a huge challenge. Here, we report a general approach to anchor Pt single-atom intercalated in layered double hydroxide (LDH) and decipher the alternating synergy between Pt single-atom and Ni₃Fe LDH support for overall water splitting. Aided with Tafel slope, interface species evolution and control experiments, operando electrochemical impedance spectroscopy (EIS) can distinguish interface charge transport and elementary reactions during hydrogen and oxygen evolution reactions (HER and OER). For HER, interlayer Pt single-atom vastly enhances electron transferability of LDH support, and Ni₃Fe LDH support accelerates water dissociation, thus resulting in a mixture of mechanisms (Heyrovsky–Volmer and Tafel–Volmer) in 1 M KOH. For OER, interlayer Pt single-atom not only prompts active phase transition from NiFe LDH to Ni^2+δFe^3+ζO_xH_y, but also optimizes OER intrinsic activity of Ni^2+δ–O–Fe^3+ζ in Ni^2+δFe^3+ζO_xH_y. Overall, we provide a referential paradigm for SACs synthesis strategy and unscrambling its alternating synergy.

High entropy materials (HEMs) are attracting significant attention due to their unique structure and unprecedented application potential in many fields. Herein, a novel low temperature strategy for preparing high entropy (Co, Cu, Fe, Mn, Ni)₃O₄ oxides with a single-phase, the Fdm spinel structure, is developed via solvothermal synthesis followed by annealing. This is the first time that high entropy oxides were fabricated successfully at low temperature. The as-prepared high entropy oxides possess five highly dispersed metal species, and the average particle size is approximately 5 nm, which is the smallest nanometer size of the high entropy oxides that has been reported so far. By considering their unique physical and chemical properties, the resultant high entropy oxides exhibit an excellent performance for water oxidation. Hence, this work provides a new synthetic strategy for high entropy oxides to solve the bottlenecks encountered by traditional methods and broaden their application areas.

Significant efforts have been devoted to design and develop supported catalysts for electrochemical energy conversion and storage systems since they have enhanced electrocatalytic activity. The interfacial effects between the support and catalyst could control electron distribution, tune intermediate adsorption, prevent catalysts from dense aggregation, and improve stability. In this review, we summarize the recent progress in supported catalysts for promoting electrocatalysis relevant to renewable energy technologies. It starts with the rational selection and synthesis of supported catalysts, and strategies to improve the support. Then, recent improvements in the vital electrocatalytic reactions (hydrogen evolution reaction (HER), oxygen reduction reaction (ORR), CO₂ reduce reaction (CO₂RR), oxygen evolution reaction (OER), etc.) are discussed, respectively. Finally, the challenges and opportunities are presented for this promising field.

Dynamic evolution processes in electrocatalysis, including structure evolution of electrocatalysts, characterization methods and regulation strategies for dynamic evolution in electrocatalysis.