Polydopamine and Nafion bi‐layer passivation modified CdS photoanode for photoelectrochemical hydrogen evolution

Abstract

Photoelectrochemical (PEC) hydrogen production, using sunlight, is a clean, renewable, and eco-friendly strategy for solar fuel production. To reduce the rate of photogenerated carriers' recombination and chemically corrosion of CdS photoanode, a composite component surface state passivation layer was introduced. The polydopamine (PDA) and Nafion co-modified CdS nanorods were successfully prepared by simple electropolymerization and dipping methods. The inherent adhesion of PDA can make it adhere well to CdS nanorods to improve the surface defects of CdS, and it can also promote the assembly of Nafion coating. The mechanism of PDA/Nafion bi-layer passivation on CdS was analyzed by steady-state/time-resolved photoluminescence spectra and electron paramagnetic resonance. The optimized CdS/PDA/Nafion photoanode exhibits highly improved PEC water splitting activity and stability under visible light. It is highly anticipated that this multifunctional polymer passivation layer will provide new routes to practically engineer photoanodes in PEC hydrogen production devices.

P25-induced polydopamine conformal assembly on Cu2O polyhedra for hydrophilic and stable photoelectrochemical performance

“…It's worth noting that the defect state emission becomes smaller after loading the PDA overlayer, which is proof of the passivation effect arising from PDA effectively reducing the electrode surface defects. 24…”

“…Results and discussion The XRD pattern of PDA is absent due to the amorphous nature of the polymer. 24 XPS analysis was conducted to confirm the surface chemical state details. Fig.…”

“…It's worth noting that the defect state emission becomes smaller after loading the PDA overlayer, which is proof of the passivation effect arising from PDA effectively reducing the electrode surface defects. 24 Time resolved photoluminescence (TRPL) spectra were thereafter recorded and are displayed in Fig. 5(b), providing a quantitative lifetime of the photogenerated carrier.…”

“…The peaks at 36.51 and 60.41 are ascribed to the (111) and (220) crystal planes of Cu 2 O crystals. A weak peak belonging to the anatase (101) crystal plane appears at 25.31, indicating the presence of P25 nanoparticles in Cu 2 O/PDA/P25 and Cu 2 O/P25.The XRD pattern of PDA is absent due to the amorphous nature of the polymer 24.…”

Mussel-Inspired Interfacial Modification for Ultra-Stable MoS2 Lubricating Films with Improved Tribological Behavior on Nano-Textured ZnO Surfaces Using the AACVD Method

“…MoS 2 , a typical two-dimensional (2D) layered transition-metal dichalcogenide, has been widely used as a solid lubricant in the aviation field because of the excellent vacuum lubrication performance induced by its high interlayer anisotropy. − However, MoS 2 tends to be oxidized by oxygen and water vapor in the atmospheric environment, which reduces the friction properties and shortens the wear life. , Research has shown that metal doping − is a simple and economical method to improve the mechanical and tribological properties of MoS 2 solid lubricating materials. Meanwhile, the construction of micro-/nanotexture surfaces can not only improve the bearing capacity as power bearings but can also increase the storage capacity of lubricating materials and prolong the service life. − On the other hand, the poor adhesion between MoS 2 and a matrix has always been a perplexing problem. − Inspired by mussel adhesion proteins, polydopamine (PDA) formed by self-polymerization of dopamine is a polymer with outstanding adsorption performances, which can be adsorbed on various materials through strong covalent and non-covalent bonds to serve as an effective protective layer for nanostructures. − In particular, the rich functional groups (e.g., −NH 2 , −OH and catechol groups) on the surface of PDA have strong chelating ability for transition-metal ions (e.g., Zn 2+ , Fe 3+ , and Mo 4+ ), − which is beneficial to provide a reaction platform as a nucleation site to form a unique solid core–shell structure, thus improving the adhesion and load-bearing capacity of the film.…”