Regulating the metabolites through SiC, ZnO, and SnO2 nano-photocatalysts for elevating efficiency of photo fermentative bioH2 from Arundo donax L.

Abstract

Photo-fermentation offers a promising roadmap for hydrogen production through their ability to harness light energy, however, its lower conversion efficiency is the major bottleneck for its realization. This study investigates the catalytic role of wideband gap nano-photocatalysts (SiC, ZnO, and SnO2) in enhancing hydrogen generation from Arundo donax L. Physio-optical characteristics of SiC, ZnO, and SnO2 nano-photocatalysts were assessed through SEM, XRD, and FT-IR which confirmed that incorporated nano-photocatalysts are spherical with uniform size distribution and there is no secondary phase. Hydrogen production experiments with varying nano-photocatalyst concentrations revealed that the maximum hydrogen yield of 104 and 98.83 mL/g was achieved with SiC and ZnO, respectively, at loading concentration of 200 mg/L, whereas 69.30 mL/g were observed with 100 mg/L of SnO2. The incorporation of SIC, ZnO, and SnO2 nano-photocatalyst permitted to increase the hydrogen content in overall gas production by 41 %, 37.34 %, and 18.26 % as compared to the control group. The increase in hydrogen production is related to the enhanced e-h pair separation lifetime of SiC, confirmed from PL spectroscopy. Addition of SiC caused a longer availability of electrons that helped to increase the metabolic rate by 38 % and 40.29 % in energy conversion efficiency (ECE). ANOVA results revealed significant differences between the control and maximum values of CHP, HC%, byproducts, and ECE. Tukey pairwise comparisons showed that SiC and ZnO had non-significant differences at 200 mg/L but both significantly outperformed SnO2 at 100 mg/L. Thus, the selection of suitable catalysts photocatalysts with enhanced e-h pair separation lifetime may offer promising prospects for sustainable energy technologies by enhancing biohydrogen production.