Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2020 Apr 1;2(4):908-920.
doi: 10.1016/j.matt.2020.01.002.

Disturbance-Promoted Unconventional and Rapid Fabrication of Self-Healable Noble Metal Gels for (Photo-)Electrocatalysis

Affiliations
Free PMC article

Disturbance-Promoted Unconventional and Rapid Fabrication of Self-Healable Noble Metal Gels for (Photo-)Electrocatalysis

Ran Du et al. Matter. .
Free PMC article

Abstract

As an emerging class of porous materials, noble metal aerogels (NMAs) have drawn tremendous attention and displayed unprecedented potential in diverse fields. However, the development of NMAs is impeded by the fabrication methods because of their time- and cost-consuming procedures, limited generality, and elusive understanding of the formation mechanisms. Here, by revealing the self-healing behavior of noble metal gels and applying it in the gelation process at a disturbing environment, an unconventional and conceptually new strategy, i.e., a disturbance-promoted gelation method, is developed by introducing an external force field. It overcomes the diffusion limitation in the gelation process, thus producing monolithic gels within 1-10 min at room temperature, 2-4 orders of magnitude faster than for most reported methods. Moreover, versatile NMAs are acquired by using this method, and their superior (photo-)electrocatalytic properties are demonstrated for the first time in light of combined catalytic and optic properties.

Keywords: aerogels; electrocatalysis; ethanol oxidation reaction; gels; noble metals; photoelectrocatalysis; plasmonics; rapid; self-healing; sol-gel.

Conflict of interest statement

The authors declare no competing interests.

Figures

None
Figure 1
Figure 1
Demonstration and Characterization of the Stirring-Promoted Rapid Fabrication of Gold Gels (A) Photographs of the stirring-directed gelation process of a gold NP solution (0.2 mM, 10 mL, left) induced by NH4F and the corresponding aerogel (right). For a better demonstration, the aerogel was created from ~800-mL solutions. (B) Optical microscopy image of the as-formed gold aggregates after stirring for 45 s. (C and D) SEM image (C) and TEM image (D) of the obtained gold aerogel. (E) The gelation process of gold NP solutions under stirring at 600 rpm for 0, 10, 30, 60, 90, and 120 s. (F) Time-lapse UV-vis absorption intensities obtained at 510 nm for the gelation system under stirring at 600 rpm for 0, 45, and 120 s. (G) Summary of the gelation time of noble metal gels reported in the literature and in this work versus the initial metal salt concentrations (cM). References denoted by red dots: a, Wen et al.; b, Du et al.; c, Zhu et al.; d, Shi et al.; e, Naskar et al.; f, Tang et al.; g, Bigall et al.; h, Liu et al.; i, Wen et al.; j, Cai et al.; k, Gao et al.; l,Yazdan-Abad et al.; m, Shi et al.
Figure 2
Figure 2
The Mechanisms for the Disturbance-Promoted Gelation (A) Gold NP solutions destabilized by NH4F in different environments (undisturbed, stirring for 2 min, shaking for 20 s, and bubbling for 2 min with N2). The photo was taken 2 min after the corresponding treatment. (B) Time-lapse photographs of the disturbing-promoted gelation process of gold NP solutions (triggered by NH4F) by manually shaking for 0, 3, 10, and 30 s. (C and D) Proposed model for stirring-promoted gelation (C) and the role of the self-healing properties and the disturbing environment played in this process (D). (E–G) MC simulation under different disturbing conditions (simulated for different maximum step lengths). Distribution of (E) the required steps to form one single aggregate, (F) the number of aggregates after 5,000 MC steps, and (G) the average radius of gyration (Rg) of the resulting aggregates after 15,000 MC steps.
Figure 3
Figure 3
Generality of the Disturbance-Promoted Gelation (A–C) Stirring-promoted gelation of diverse gold gels. (A) NaBH4-initiated gelation from NaCA-stabilized gold NP solutions with cM ranging from 0.02 mM to 5.0 mM, (B) NaBH4-initiated gelation from gold NP solutions stabilized by different ligands (cM = 0.2 mM), and (C) gelation of NaCA-stabilized gold NP solutions triggered by different initiators (cM = 0.2 mM). (D–I) NMAs with different compositions. (D) Ag, (E) Pd, (F) Rh, (G) Au-Ag, (H) Au-Pd, and (I) Au-Pt. The inset photograph in (F) shows the residual of the Rh aerogel after spontaneously burning in air. (J–M) Energy-dispersive X-ray mapping of multimetallic aerogels made of (J) Au-Pd, (K) Au-Rh, (L) Au-Pd-Pt, and (M) core-shell Au-Pt. (J), (K), and (L) were prepared by a two-step method, while (M) was prepared by the dynamic shelling approach.
Figure 4
Figure 4
Application of NMAs in Electrocatalysis and Photoelectrocatalysis (A) Electrocatalytic performance of the EOR with commercial and various aerogel catalysts. (B) Summarized If and If/Ib of various catalysts. Au-Pt-cs denotes the core-shell-structured Au-Pt aerogel, and the suffix “L” denotes that the test was conducted under white-light illumination at 133.6 mW cm−2. (C) Dependence of If of the Au-Pd-Pt aerogel on the input light power density. (D) Light response behavior on an Au-Pd-Pt aerogel electrode in the course of a chronoamperometry test. All tests were performed in nitrogen-saturated 1.0 M KOH + 1.0 M ethanol aqueous solution.

Similar articles

See all similar articles

References

    1. Gesser H., Goswami P. Aerogels and related porous materials. Chem. Rev. 1989;89:765–788.
    1. Hüsing N., Schubert U. Aerogels—airy materials: chemistry, structure, and properties. Angew. Chem. Int. Ed. 1998;37:22–45. - PubMed
    1. Ziegler C., Wolf A., Liu W., Herrmann A.-K., Gaponik N., Eychmüller A. Modern inorganic aerogels. Angew. Chem. Int. Ed. 2017;56:13200–13221. - PubMed
    1. Kistler S.S. Coherent expanded aerogels and jellies. Nature. 1931;127:741.
    1. Du R., Zhang N., Xu H., Mao N., Duan W., Wang J., Zhao Q., Liu Z., Zhang J. CMP aerogels: ultrahigh-surface-area carbon-based monolithic materials with superb sorption performance. Adv. Mater. 2014;26:8053–8058. - PubMed

LinkOut - more resources

Feedback