Synthesis of azo polymers and their catalytic performance in hydrogen production via NaBH4 methanolysis

Abstract

The extensive use of fossil fuels has a profound impact on ecosystems and contributes to global warming through the emission of greenhouse gases. To mitigate these effects, alternative energy sources such as hydrogen are crucial. In this study, a green synthesis approach was used to prepare an azo cross-linked polymer containing 4-aminophenyl ether and resorcinol. The synthesized polymer was thoroughly characterized by FT-IR, BET, TGA, Zeta Potential and SEM-EDS analyses. The catalytic performance of the polymer in hydrogen production from NaBH4 via methanolysis was then investigated. Various parameters affecting hydrogen production, including catalyst and NaBH4 amounts, methanol volume and temperature, were systematically investigated to identify the optimum conditions. The polymer exhibited maximum hydrogen generation rate (HGR) of 12,619 mL H2 min⁻¹ gcat⁻¹ at 60 °C, respectively, with an activation energy of 24.22 kJ mol⁻¹. After optimization, the reusability of the polymer was evaluated over five cycles and the theoretical hydrogen generation rates were consistently achieved; however, the hydrogen generation time increased with each subsequent cycle. The primary objective of this research was to highlight novel azo linked polymers with potent catalytic activity in hydrogen generation, demonstrating the significant potential of the polymer to advance hydrogen generation. Ultimately, this study highlights the promising role of azo cross-linked polymers as effective catalysts for hydrogen production, offering new avenues and perspectives towards sustainable energy solutions.