TY - JOUR
T1 - Asymmetric electrokinetic proton transport through 2D nanofluidic heterojunctions
AU - Zhang, Xiaopeng
AU - Wen, Qi
AU - Wang, Lili
AU - Ding, Liping
AU - Yang, Jinlei
AU - Ji, Danyan
AU - Zhang, Yanbing
AU - Jiang, Lei
AU - Guo, Wei
PY - 2019/4/23
Y1 - 2019/4/23
N2 - Nanofluidic ion transport in nacre-like 2D layered materials attracts broad research interest due to subnanometer confined space and versatile surface chemistry for precisely ionic sieving and ultrafast water permeation. Currently, most of the 2D-material-based nanofluidic systems are homogeneous, and the investigations of proton conduction therein are restricted to symmetric transport behaviors. It remains a great challenge to endow the 2D nanofluidic systems with asymmetric proton transport characteristics and adaptive responsibilities. Herein, we report the asymmetric proton transport phenomena through a 2D nanofluidic heterojunction membrane under three different types of electrokinetic driving force, that is, the external electric field, the transmembrane concentration gradient, and the hydraulic pressure difference. The heterogeneous 2D nanofluidic membrane comprises of sequentially stacked negatively and positively charged graphene oxide (n-GO and p-GO) multilayers. We find that the preferential direction for proton transport is opposite under the three types of electrokinetic driving force. The preferential direction for electric-field-driven proton transport is from the n-GO multilayers to the p-GO multilayers, showing rectified behaviors. Intriguingly, when the transmembrane concentration difference and the hydraulic flow are used as the driving force, a preferred diffusive and streaming proton current is found in the reverse direction, from the p-GO to the n-GO multilayers. The asymmetric proton transport phenomena are explained in terms of asymmetric proton concentration polarization and difference in proton selectivity. The membrane-scale heterogeneous 2D nanofluidic devices with electrokinetically controlled asymmetric proton flow provide a facile and general strategy for potential applications in biomimetic energy conversion and chemical sensing.
AB - Nanofluidic ion transport in nacre-like 2D layered materials attracts broad research interest due to subnanometer confined space and versatile surface chemistry for precisely ionic sieving and ultrafast water permeation. Currently, most of the 2D-material-based nanofluidic systems are homogeneous, and the investigations of proton conduction therein are restricted to symmetric transport behaviors. It remains a great challenge to endow the 2D nanofluidic systems with asymmetric proton transport characteristics and adaptive responsibilities. Herein, we report the asymmetric proton transport phenomena through a 2D nanofluidic heterojunction membrane under three different types of electrokinetic driving force, that is, the external electric field, the transmembrane concentration gradient, and the hydraulic pressure difference. The heterogeneous 2D nanofluidic membrane comprises of sequentially stacked negatively and positively charged graphene oxide (n-GO and p-GO) multilayers. We find that the preferential direction for proton transport is opposite under the three types of electrokinetic driving force. The preferential direction for electric-field-driven proton transport is from the n-GO multilayers to the p-GO multilayers, showing rectified behaviors. Intriguingly, when the transmembrane concentration difference and the hydraulic flow are used as the driving force, a preferred diffusive and streaming proton current is found in the reverse direction, from the p-GO to the n-GO multilayers. The asymmetric proton transport phenomena are explained in terms of asymmetric proton concentration polarization and difference in proton selectivity. The membrane-scale heterogeneous 2D nanofluidic devices with electrokinetically controlled asymmetric proton flow provide a facile and general strategy for potential applications in biomimetic energy conversion and chemical sensing.
KW - 2D layered materials
KW - energy conversion
KW - ionic rectification
KW - nanofluidics
KW - proton transport
UR - http://www.scopus.com/inward/record.url?scp=85064709438&partnerID=8YFLogxK
U2 - 10.1021/acsnano.8b09285
DO - 10.1021/acsnano.8b09285
M3 - Article
C2 - 30865824
AN - SCOPUS:85064709438
SN - 1936-0851
VL - 13
SP - 4238
EP - 4245
JO - ACS Nano
JF - ACS Nano
IS - 4
ER -