Polypyrrole Serving as Multifunctional Surface Modifier for Photoanode Enables Efficient Photoelectrochemical Water Oxidation

Abstract

Conjugated polymer polypyrrole (PPy) with high electrical conductivity and excellent photothermal effect has been adopted as multifunctional surface modifier on ternary metal sulfide (CdIn2S4, CIS) photoanode for photoelectrochemical (PEC) water splitting for the first time. As a p‐type conducting polymer, PPy forms p–n junction with n‐type CIS to relieve the bulk carrier recombination. Besides, the incorporation of Ni ions into PPy matrix further enhances the surface charge carrier transfer at photoanode/electrolyte interfaces. Furthermore, the excellent photothermal effect of PPy produces heat under near‐infrared (NIR) irradiation, which can elevate the temperature of CIS photoanode in situ and further enhance the PEC performance. As a result, the optimum CIS/Ni‐PPy photoanode shows an obviously enhanced photocurrent density of 6.07 mA cm−2 at 1.23 V versus reversible hydrogen electrode under the irradiation of AM 1.5G combined with NIR light, which is the highest among all the CIS based photoanodes reported to date. The synergetic effect of Ni‐PPy significantly suppresses the bulk recombination, decreases the carrier transfer resistance, and accelerates the surface water oxidation dynamics, resulting in high carrier injection efficiency over 80% in the measured potential range. The universality of the multifunctional surface modifier strategy has also been confirmed on metal oxide photoanode.

Recent research progress on operational stability of metal oxide/sulfide photoanodes in photoelectrochemical cells

“…The most intuitive manifestation of the stability of PEC water-splitting devices is the variation in performance, including J, STH, and the onset potential (Von) [46]. Among them, the changing trends of J are the most direct evidence, and the relationship of J with time can be clearly expressed by performing an I-T test.…”

Designing Photothermal Superhydrophobic PET Fabrics via In Situ Polymerization and 1,4-Conjugation Addition Reaction

“…16,17 These materials usually include metallic materials, 18,19 carbonaceous materials, 20−24 and conducting polymers. 25 However, photothermal conversion materials face serious rainwater corrosion and environmental pollutant pollution problems during long-term outdoor operation, which significantly affects their performance stability and service life. Meanwhile, the superhydrophobic surface with a water contact angle (WCA) larger than 150°and sliding hysteresis angle less than 10°can possess the self-cleaning ability against rainwater and contaminants.…”

“…Among them, photothermal conversion technology is the most direct application of solar energy. Photothermal conversion materials which can directly convert absorbed light energy into thermal energy have been widely used in photothermal energy storage, , photothermal deicing, , seawater desalination, , and light-driven. , These materials usually include metallic materials, , carbonaceous materials, − and conducting polymers . However, photothermal conversion materials face serious rainwater corrosion and environmental pollutant pollution problems during long-term outdoor operation, which significantly affects their performance stability and service life.…”

Photothermal-Effect-Enhanced Photoelectrochemical Water Splitting in MXene-Nanosheet-Modified ZnO Nanorod Arrays

“…As we know, increasing the temperature of the PEC reaction can accelerate the charge and mass transfer, thus improving the reaction activities. 16 However, the conventional heating method is to raise the temperature of the whole PEC system. Considering that the reactions only occur on the surface of photoelectrodes, the traditional heating method would waste energy and destabilize the PEC system because the heated electrolyte evaporates quickly.…”

“…The photothermal NiCo 2 O 4 cocatalyst elevates the temperature of photoanodes moderately under near-infrared (NIR) light irradiation, resulting in enhanced charge transport and water oxidation kinetics. As we know, increasing the temperature of the PEC reaction can accelerate the charge and mass transfer, thus improving the reaction activities . However, the conventional heating method is to raise the temperature of the whole PEC system.…”