Chlorella vulgaris on two-dimensional Ruddlesden–Popper phase ca_n-1mn_n-3Nb₃O_3n+1 (n = 4, 5, 6) perovskite nanosheets for hydrogen generation

Amid the increasing focus on sustainable energy, hydrogen generation through photocatalysis has garnered substantial attention in recent years. Given their distinctive electronic, optical, and structural properties, two-dimensional perovskite nanosheets have surfaced as promising contenders as photocatalysts. Here we present a systematic exploration of Ruddlesden-Popper phase Ca_n-1Mn_n-3Nb₃O_3n+1²⁻ (n = 4,5,6) perovskite (CMNO) nanosheets with distinct layers (n = 4, 5, and 6), synthesized via exfoliation approach, for enhanced physicochemical properties and catalytic performances. Rigorous characterizations supported by the Tauc plot and Mott-Schottky analysis reveal the crystal structures, varied bandgaps, and an n-type semiconductor behavior from the CMNO nanosheets. In a novel approach to enhance its photo-absorption, Chlorella vulgaris microalgae, strategically layered onto the CMNO nanosheets, consequently exhibit significant improvements in the onset potential and current density, especially for the CMNO (n = 6) nanosheet. This research lays a foundation for understanding the tailored composition and layer-dependent properties of CMNO nanosheets, propelling their potential application in efficient hydrogen generation through photoelectrochemical water splitting for sustainable energy technologies.