NiMoO4 Nanoflower Electrocatalyst via AACVD

The patent replaces expensive noble metal catalysts with inexpensive transition metal-based electrocatalysts (such as nickel ferrite, cobalt phosphide, nickel molybdate) that can be synthesized from abundant, low-cost precursors. These earth-abundant materials provide comparable catalytic activity for water oxidation without the high cost and scarcity issues of Ir/Ru oxides, directly addressing the technical contradiction between catalytic performance and material cost.

The patent employs aerosol-assisted chemical vapor deposition (AACVD) to precisely control the composition, crystal structure, and morphology of transition metal electrocatalysts. By adjusting deposition parameters (temperature, time, precursor ratios), the patent optimizes the electronic structure and surface properties of the catalysts to achieve high catalytic activity comparable to noble metals, while using abundant transition metal elements instead of rare noble metals.

The patent replaces conventional mechanical mixing and hydrothermal synthesis methods with aerosol-assisted chemical vapor deposition (AACVD). This vapor-phase deposition technique allows precursors to be delivered as aerosols that decompose and form highly crystalline electrocatalyst films directly on substrates, eliminating the need for complex mechanical processing, filtration, and drying steps while producing materials with superior crystallinity and controlled morphology that enhance electroactive sites.

The patent utilizes phase transition during the AACVD process where precursor aerosols undergo vaporization, decomposition, and crystallization upon contact with the heated substrate. This controlled phase transition enables the formation of highly crystalline electrocatalyst phases (such as nickel ferrite, cobalt phosphide) with well-defined crystal structures and exposed active facets, maximizing electroactive sites while maintaining a relatively simple one-step deposition process.

The patent designs composite electrocatalyst structures combining different transition metal elements (e.g., nickel ferrite, cobalt phosphide, nickel molybdate) with complementary electronic and catalytic properties. These composite materials create synergistic effects that optimize the electronic structure, reduce charge transfer resistance, and lower overpotentials for water oxidation, thereby improving energy efficiency compared to single-metal catalysts or conventional noble metal systems.

The patent employs AACVD to precisely control the stoichiometry, crystallinity, and surface morphology of transition metal electrocatalysts. By optimizing deposition temperature, time, and precursor composition, the patent creates catalysts with tailored electronic structures and surface properties that facilitate efficient charge transfer and reduce overpotentials, thereby improving the energy efficiency of water oxidation reactions.