Highly effective CNT-based magnetic pn-junction nanocomposite photocatalyst/solar-energy material for hazmat conversion to hydrogen fuel

Abstract

Hazmat conversion to hydrogen using low-cost effective eco-friendly solar energy active materials is a sustainable strategy for environmental remediation and provision of future green fuel. In this paper, a novel magnetic pn-junction nanocomposite was rationally designed and synthesized through a facile hydrothermal route using affordable chemicals in the absence and presence of CNT (carbon nanotube). The easy recyclable/re-collectable CNT-based magnetic materials with the scaling up capability synthesized here were applied as effective nanoenergy materials for photocatalytic conversion of H2S feed to hydrogen fuel. The maximum hydrogen production was attained for the pn-junction nanocomposite photocatalyst at the molar ratio 1:2 of p to n (rate:5652μmolH2g.h) and boosted 60% by adding CNT. Transient photocurrent, impedance, fluorescence and electron paramagnetic resonance (EPR) investigations revealed that the charge recombination is reduced in the presence of CNT and hence the photogenerated e−/h+ pairs can more effectively be utilized in the hazmat-to-fuel conversion process. The junction formation was approved at an atomistic scale through HRTEM observation. Furthermore, the magnetic property of the synthesized nanocomposite photocatalyst was improved in the presence of CNT and discussed in detail from physicochemical standpoint using VSM (vibrating sample magnetometric) and XPS (X-ray photoelectron spectroscopic) evidence.