Organic alginate encapsulated rGO-CdS millispheres for remarkable photocatalytic solar hydrogen production

Abstract

Herein, hydrogen generation through photocatalytic water splitting is explored using a recyclable, environment-friendly organic alginate hydrogel-encapsulated rGO-CdS millisphere photocatalyst under solar irradiation (1 Sun) using a solar simulator. Effective incorporation of rGO-CdS nanoparticles into a network of organic polymer sodium alginate is achieved while conserving the pore structures. A remarkable (79.68 mmol g rGO-CdS−1 h−1) solar hydrogen production is observed for the as-developed photocatalysts, using full-band solar irradiation; an AQE of 19.51% is achieved using of 420 nm band pass filter. The extent of hydration (pre-adsorption and dynamic adsorption of water) on the alginate network strongly influences the rate and extent of hydrogen generation. Instead of the conventionally used powder photocatalyst, millisphere beads make the continuous operation of the photoreactor easier. A steady, constant rate of continuous, sustainable hydrogen generation is achieved by employing a laboratory-scale flow reactor. The toxic effects of CdS is minimised (evidenced from cell viability test) through encapsulation by sodium alginate and promoting performance by incorporating rGO.