Open Chemistry (Dec 2024)
Magnetite–poly-1H pyrrole dendritic nanocomposite seeded on poly-1H pyrrole: A promising photocathode for green hydrogen generation from sanitation water without using external sacrificing agent
Abstract
The Fe3O4 magnetite–poly-1H pyrrole dendritic nanocomposite seeded on additional poly-1H pyrrole film, denoted as Fe3O4-P1HP/P1HP, is synthesized by oxidative polymerization utilizing (Fe(NO3)3·5H2O for the pyrrole monomer. The resulting nanocomposite exhibits a notable bandgap of 1.97 eV and demonstrates broad optical absorption up to 625 nm. The structure of each particle consists of numerous smaller internal particles, which are composed of nanofibers of approximately 2.0 nm in length and porous structures of around 5.0 nm. These porous structures cluster together to form a larger configuration, with an overall diameter of ∼230 nm and a length of approximately 300 nm, giving the composite a nano-cactus-like appearance. The fabricated Fe3O4–P1HP/P1HP photocathode is inserted into a three-electrode cell to facilitate green hydrogen production from sanitation water without the need for any external sacrificial agent. The performance of H2 gas generation is assessed by measuring the photocurrent density (J ph) under light, which serves as an indicator of the efficiency of hydrogen production. The J ph value reaches −0.23 mA/cm² under light conditions. The highest J ph values of −0.164 and −0.158 mA/cm² are observed at wavelengths of 340 and 440 nm, respectively. However, as the wavelength reaches 540 nm, the J ph value decreases to −0.134 mA/cm² and drops to its lowest point of −0.128 mA/cm² at 730 nm, which is comparable to the dark current (J o). The fabricated photocathode demonstrates a promising hydrogen generation rate of 90 µmol/h cm², reflecting its potential for commercial applications. The combination of this impressive hydrogen production rate, along with the photocathode’s cost-effectiveness and straightforward fabrication process, suggests that this technology could be commercially viable for converting sanitation water into hydrogen gas.
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