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Light‐Driven Active Proton Transport through Photoacid‐ and Photobase‐Doped Janus Graphene Oxide Membranes
Author(s) -
Wang Lili,
Wen Qi,
Jia Pan,
Jia Meijuan,
Lu Diannan,
Sun Xiaoming,
Jiang Lei,
Guo Wei
Publication year - 2019
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201903029
Subject(s) - membrane , materials science , proton transport , graphene , janus , oxide , photocurrent , electrochemical gradient , proton , ion transporter , chemical engineering , photochemistry , ion , nanotechnology , optoelectronics , chemistry , organic chemistry , biochemistry , physics , quantum mechanics , engineering , metallurgy
Biological electrogenic systems use protein‐based ionic pumps to move salt ions uphill across a cell membrane to accumulate an ion concentration gradient from the equilibrium physiological environment. Toward high‐performance and robust artificial electric organs, attaining an antigradient ion transport mode by fully abiotic materials remains a great challenge. Herein, a light‐driven proton pump transport phenomenon through a Janus graphene oxide membrane (JGOM) is reported. The JGOM is fabricated by sequential deposition of graphene oxide (GO) nanosheets modified with photobase (BOH) and photoacid (HA) molecules. Upon ultraviolet light illumination, the generation of a net protonic photocurrent through the JGOM, from the HA‐GO to the BOH‐GO side, is observed. The directional proton flow can thus establish a transmembrane proton concentration gradient of up to 0.8 pH units mm −2 membrane area at a proton transport rate of 3.0 mol h −1 m −2 . Against a concentration gradient, antigradient proton transport can be achieved. The working principle is explained in terms of asymmetric surface charge polarization on HA‐GO and BOH‐GO multilayers triggered by photoisomerization reactions, and the consequent intramembrane proton concentration gradient. The implementation of membrane‐scale light‐harvesting 2D nanofluidic system that mimics the charge process of the bioelectric organs makes a straightforward step toward artificial electrogenic and photosynthetic applications.