(599f) Superwetting Nanoarray Electrodes for Gas-Involved Electrocatalysis

Superwetting Nanoarray Electrodes for Gas-Involved Electrocatalysis

Yingjie Li,  Wenwen Xu, Zhiyi Lu, Xiaoming Sun*

Beijing University of Chemical Technology, Beijing 100029, China, Email: sunxm@mail.buct.edu.cn

Electrochemical gas-involved reactions can be divided into two types: gas-evolution
reaction and gas-consumption
reaction, both of which are crucial for a variety of energy
conversion processes and industries (e.g. HER and ORR). For gas-evolution reaciton,
if generated gas bubbles pin at the electrode surface and cannot escape from
the surface in time, the accumulated bubbles will reduce the effective
electrode surface area, increase diffusion resistance and enlarge polarization
effect, resulting in more energy consumption. How to construct a novel electrode
to promote gas bubble release is critical for improving the electrochemical efficiency
besides activity improvement. Inspired from bio-inspired superwetting surfaces,
we found that the interface behavior of electrode could be tuned by surface
architecture construction, for example, transferring from aerophobic to
superaerophobic by engineering a series of nanoarray electrode, eg. MoS₂ (Fig.
1), pine-shaped Pt, NiFe LDHs and Cu films ^[1-7]. This
kind of superaerophobic electrodes could decrease the critical size of gas
overflowing from the surface by cutting the three phase contact lines into
discontinue dots, and thus reduce the diffused impedance and maintain the
integrity of the solid−liquid interface that is necessary for electrocatalysis
(e.g. water splitting and hydrazine fuel cells). On the other hand, for gas-consumption reaction, the construction of nanoarray ¡°superaerophilic¡±
electrode could accelerate gas diffusion to reaction zone via gas-phase to solve the issue of low solubility and slow diffusion of gases in traditional
electrocatalysiss reaction system with limited current density (eg., ORR).  Therefore, the construction of superwetting nanoarray electrodes is imperative to
improve gas
transport at electrodes surface and to enhance activity and stability of electrodes.

Fig.
1 (A) Schematic illustration
of adhesion behaviors of gas bubbles on flat film (left) and nanostructured
film (right), (B) and (C) Adhesive forces measurements of the gas bubbles on
flat and nanostructured MoS₂ films, (D) Polarization curves (without
IR-correction) of MoS₂ and Pt/C catalysts (E) Stability testing of
flat and nanostructured MoS₂ electrodes

References

[1] Z. Lu, W. Zhu, X. Yu, H. Zhang,
Y. Li, X. Sun, X. Wang, H. Wang, J. Wang, J. Luo, X. Lei, L. Jiang. Adv. Mater.
26 (2014), 2683-2687.

[2] Y. Li, H. Zhang, T. Xu, Z. Lu,
X. Wu, P. Wan, X. Sun, L. Jiang. Adv. Funct. Mater. 25 (2015), 1737-1744.

[3] Z. Lu, M. Sun, T. Xu, Y. Li,
W. Xu, Z. Chang, Y. Ding, X. Sun, L. Jiang. Adv. Mater. 27 (2015), 2361-2366.

[4] X. Liu, Z. Chang, L. Luo, T.
Xu, X. Lei, J. Liu, X. Sun. Chem. Mater., 26 (2014), 1889-1895.

[5] M. Sun , Z. Lu , L. Luo, Z. Chang ,  X. Sun. Nanoscale, 8 (2016),
1479-1484

[6] W. Xu,
Z. Lu, P. Wan, Y. Kuang,  X. Sun.
Small, 12 (2016), 2492¨C2498

[7] M.
Jiang, Y. Li, Z. Lu, X. Sun,  X.
Duan. Inorg. Chem. Front. 2016, DOI: 10.1039/C5QI00232J.

Biography

Professor Xiaoming Sun gained his B.S. degree and Ph.D. in Department
of Chemistry, Tsinghua University in 2000 and 2005, respectively. After
postdoctoral work at Stanford University, he joined State Key Laboratory of
Chemical Resource Engineering, Beijing University of Chemical Technology at
2008. His main research interests focus on separation and assembly of inorganic
nanostructures, synthesis and separation of carbon nanomaterials and their
composites, and structure control, opto-/electro-property investigations of
nanoarrays and  superwetting nanoarray electrodes for energy sciences.
He has authored 63 journal articles (eg. J. Am. Chem. Soc., Angew. Chem. Int.
Ed., Adv. Mater., ACS Nano.), which have been cited >4600
times.