Highly adsorptive/effective rGO/pn-junction nanocomposite to generate hydrogen fuel using H2S: Rational photocatalyst design and magnetic boosting

Instead of splitting water molecules, an energy-efficient, eco-friendly alternative to produce hydrogen fuel is to utilize H2S hazmat, generated on a large scale by sour oil/gas industries. For this conversion to fuel, the rational design and facile synthesis of effective, affordable, environmental photocatalyst/solar-energy materials with high reactant-adsorbing capacity are crucial from a practical standpoint. Herein, a novel rGO/CoMn2O4(p)-ZnO(n) nanocomposite was synthesized via a one-pot hydrothermal route without adding any external reducing agent. This nanocomposite served as an effective, robust photocatalyst to produce hydrogen fuel from alkaline H2S feed (8381 [Formula presented]; pH 11). The superior photocatalytic activity was attributed to improved light absorption, prevention of charge recombination, and enhanced reactant-adsorption capacity. The activity of the photocatalyst was further boosted through an easy, cost-effective approach, by applying an external magnetic field to the photoreactor. This magnetically induced boosting effect (35%) witnessed for the rGO/pn was rationalized by the improved magnetization of the pn nanocomposite in the presence of rGO and, hence, a greater interaction with the applied field.