Review on Chitosan and Two-Dimensional MoS₂-Based Proton Exchange Membrane for Fuel Cell Application: Advances and Perspectives

Abstract

Chitosan is a naturally occurring polysaccharide with abundant biomass resources that attracts interest due to its unique physicochemical properties. The importance of chitosan has risen recently (a) because it is a renewable and biodegradable material and (b) because it has the ability to form a membrane. Therefore, chitosan is highly preferable for green energy applications. This review describes the most recent advancements in chitosan chemistry, emphasizing elemental modifying reactions like sulfonation, phosphorylation, phthaloylation, and chemical cross-linking. However, the major issues of the chitosan (CS)-based polymer electrolyte membrane (PEM) are attaining high proton conductivity, leakage across fuel cells, and durability. To overcome the above-mentioned issues, chitosan and the emerging class of inorganic materials 2-D transition metal dichalcogenides especially MoS 2 can be employed for proton-exchange membrane fuel cell applications. Surface functionalization of MoS 2 can open new pathways for fabricating CS/MoS 2 composite membranes. Current research also focuses on the following issues: (a) strategies for the development of PEM, (b) properties and structures of chitosan for fuel cell applications, and (c) chitosan utilization in different parts of the fuel cell. The present study also discusses progress and particular challenges that chitosan-based proton exchange membranes face. Moreover, strategies to control those issues and future aspects are discussed in detail.

Comparative Studies of Atomically Thin Proton Conductive Films to Reduce Crossover in Hydrogen Fuel Cells

“…MoS 2 is one of the most studied transition metal dichalogenides (TMD) due to its potential in both semiconductor devices and electrochemical devices . MoS 2 in the context of fuel cell applications has been used to facilitate the oxygen reduction reaction (ORR) and as a hydrogen evolution catalyst (HER) for electrolyzers. − However, it has not been explored for crossover mitigation, as it has been suggested that proton conduction through exfoliated MoS 2 flakes is not substantial . In 2022, it was suggested by Gu et al that MoS 2 devices based on a sulfurization approach allows for metal ions to diffuse through the nanocrystalline MoS 2 layer, used for memristor application .…”

Development of Sulfonated Poly(vinyl alcohol)/MoS2-Based Robust Composite Proton Exchange Membranes with Higher Selectivity

“…Recent studies showed that the incorporation of 2D layered materials in polymers has excellent potential for practical applications of PEMs. − MoS 2 nanoplatelets are the 2D layered structures like graphene sheets and provide better ionic transport and reinforcing ability in the polymer nanocomposites. MoS 2 is also used as an additive to polymers for energy applications and promotes proton transfer with additional mechanical stability. − Moreover, the exfoliation of bulk MoS 2 flakes in pure water using the ultrasonication process leads to thinning and fragmentation of the flakes. Due to fragmentation, the Mo–S bonds on basal planes break and generate many chemically reactive species and edges at those sites.…”

Sustainable Solutions for Oral Health Monitoring: Biowaste-Derived Triboelectric Nanogenerator

“…The donation of electrons is mainly due to −OH and −NH 2 . 28 Chiu et al fabricated TENG based on chitosan−glycerol− silicon for self-charging gesture sensors. 29 PVA and chitosanbased composites are versatile and flexible biopolymers that can be used as triboelectric materials owing to their cationic positive polarity materials.…”

“…Chitosan resembles a molecular structure similar to cellulose, but the main difference is at the C-2 position; the −OH group is interchanged by −NH 2 . The donation of electrons is mainly due to −OH and −NH 2 . Chiu et al fabricated TENG based on chitosan–glycerol–silicon for self-charging gesture sensors .…”