Effective Synthesis Procedure Based on Microwave Heating of the PdCo Aerogel Electrocatalyst for Its Use in Microfluidic Devices

Earth-abundant transition metal oxides are promising alternatives to precious metal oxides as electrocatalysts for the oxygen evolution reaction (OER) and are intensively investigated for alkaline water electrolysis. OER electrocatalysis, like most other catalytic reactions, is surface-initiated, and the catalyst performance is fundamentally determined by the surface properties. Most transition metal oxide catalysts show OER activities that depend on the predominantly exposed crystal facets/surface structure. Therefore, the design of synthetic strategies to obtain the most active crystal facets is of significant research interest. In this work, rock salt NiO OER catalysts with (111) predominantly exposed facets were synthesized by a solvothermal (ST) method either heated under supercritical or microwave-assisted (MW) conditions. Particular emphasis was placed on the influence of the post annealing temperature on the structural configuration and OER activity to compare their catalytic performances. The as-prepared electrocatalysts are pure α-Ni hydroxides which were converted to rock salt NiO (111) nanosheets with hexagonal pores after heat treatment at different temperatures. The OER activity of the electrodes has been evaluated in 0.1 M KOH using geometric and intrinsic current densities via normalization by the disk area and BET area, respectively. The lowest overpotential at a geometric current density of 10 mA/cm 2 is found for samples pretreated by heating between 400 and 500 °C with a catalyst loading of 115 μg/cm 2 . Despite the very similar nature of the catalysts obtained from the two methods, the ST electrodes show a higher geometric and intrinsic current density for 500 °C pretreatment. The MW electrodes, however, achieve an optimal geometric current density for 400 °C pretreatment, while their intrinsic current density requires pretreatment over 600 °C. Interestingly, pretreated electrodes show consistently higher OER activity as compared to the poorly crystalline/less ordered hydroxide as-prepared electrocatalysts. Thus, our study highlights the importance of the synthesis method and pretreatment at an optimal temperature.

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Design strategies and applications of atomically dispersed aerogel catalysts prepared from metal hydrogel formation

Li,

Chen,

Liu

et al. 2024

J. Phys. D: Appl. Phys.

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The preparation of metal hydrogel precursors toward atomically dispersed aerogel catalysts is a captivating subject within the catalysis research domain, exhibiting promising applications in various fields. This minireview intend to summarize those novel design principles and practical applications of metal hydrogel precursors in the creation of atomically dispersed aerogel catalysts. The manuscript focuses on crucial aspects such as the meticulous selection of metal sources and initiators, the intricate process of gel preparation, a comparative analysis of different drying methods, and strategic optimization techniques to enhance the performance of metal hydrogel precursors. Moreover, this article delves into the exploration of atomically dispersed aerogel catalysts derived from metal hydrogel precursors in the realms of photocatalysis and electrocatalysis. Lastly, existing challenges are addressed, and prospective future directions for development are outlined.

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Effective Synthesis Procedure Based on Microwave Heating of the PdCo Aerogel Electrocatalyst for Its Use in Microfluidic Devices

Cited by 4 publications

References 51 publications

Acoustothermal heating in a droplet driven by lamb waves

Acoustothermal heating in a droplet driven by lamb waves

Influence of Annealing Temperature on the OER Activity of NiO(111) Nanosheets Prepared via Microwave and Solvothermal Synthesis Approaches

Design strategies and applications of atomically dispersed aerogel catalysts prepared from metal hydrogel formation

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