Preparation and Electrocatalysis Application of Pure Metallic Aerogel: A Review

Abstract

Nanomaterials are widely used in electrocatalysts due to their quantum size effect and high utilization efficiency. There are two ways to improve the activity of nanoelectrocatalysts: increasing the number of active sites and improving the inherent activity of each catalytic site. The structure of the catalyst itself can be improved by increasing the number of exposed active sites per unit mass. The high porosity and three-dimensional network structure enable aerogels to have the characteristics of a large specific surface area, exposing many active sites and bringing structural stability through the self-supporting nature of aerogels. Thus, by adjusting the compositions of aerogels, the synergetic effect introduced by alloy elements can be utilized to further improve the single-site activity. In this review, we summarized the basic preparation strategy of aerogels and extended it to the preparation of alloys and special structure aerogels. Moreover, through the eight electrocatalysis cases, the outstanding catalytic performances and broad applicability of aerogel electrocatalysts are emphasized. Finally, we predict the future development of pure metallic aerogel electrocatalysts from the perspective of preparation to application.

Highly Conductive and Mechanically Robust NiFe Alloy Aerogels: An Exceptionally Active and Durable Water Oxidation Catalyst

“…f) Comparison of electrical conductivity versus mass density for different conductive aerogels. [ 10c,14b,15 ] g) Schematic illustration of the positive contribution of metallic joints between nanowires in maintaining structural integrity under external force loadings.…”

“…As a result, none of the reported metallic aerogel catalysts was used directly as a substrate‐free electrode so far; instead, they were grounded into powders and then coated onto the substrates to fabricate the electrode, in which way the charge/mass transfer was retarded and led to depreciated stability under practical OER conditions. [ 10,11 ] Therefore, developing metallic aerogel‐based catalytic electrodes with superior mechanical robustness and electric conductivity can critically address the existing challenges, which is expected to deliver both superior OER activity and stability simultaneously under practical conditions, which however has not been realized so far.…”

Highly Selective Pd Nanosheet Aerogel Catalyst with Hybrid Strain Induced by Laser Irradiation and P Doping Postprocess

“…The 3D self‐supported network structure (Figure 1b and Figure S1a, Supporting Information) is not only beneficial to reactant diffusion and electron conduction [ 21 ] but also can avoid using carbon supports in electrocatalysis and abrogate carbon corrosion at high potentials. [ 22 ]…”

Low-Cost Biomass-Gel-Induced Conductive Polymer Networks for High-Efficiency Polysulfide Immobilization and Catalytic Conversion in Li–S Batteries

“…Aerogels have been widely applied in biomedical energy, separations, sewage treatment, construction, and specialty chemical industries because of their high surface area and tunable surface chemistry, allowing for controlled interactions with polymers, nanoparticles, small molecules, excellent chemical stability, and biological materials . At the same time, the 3D network structure and surface-active sites in the aerogel can promote the adsorption of pollutants, and the interconnected hierarchical pore structure can make it evenly deposited . However, there exist few studies on the application of an aerogel interlayer in lithium–sulfur batteries.…”