Unleashing High-Efficiency Biohydrogen Production from Arundo donax L. through interfacial charge transferring in hybrid catalytic systems by regulating metabolism

This study examines photo-fermentative biohydrogen production (PFHP) from Arundo donax L. using binary (SiC/ZnO) and ternary (SiC/ZnO/SnO 2 ) co-catalyst systems. The maximum cumulative hydrogen production of 110 mL/g and hydrogen production rate of 39.74 mL/g·h⁻¹ at 24h was achieved in ternary-C2 group of ternary system which was 73.23% higher as compared to the CG (63.5 mL/g), also outperforms binary system (97.58 mL/g, 35.81mL/g·h⁻¹) by 12.73% and 10.97%. The binary system achieved a 48.67% hydrogen content percentage, while the ternary system had 52.53%, which is 14% and 18.3% higher than the control group. Multi-interface heterojunctions occur synergistically, which is the source of the increased activity. In addition to accelerating electron migration and inhibiting electron–hole recombination, this arrangement facilitates effective interfacial charge transfer. Together, these effects produce a favourable redox environment that improves bacterial metabolism and sustains a process of hydrogen production. Maximum light absorption and charge-separation efficiency may explain the ternary system's faster metabolism and microbial activity. Ternary system hydrogen production enhanced the charge transfer by reducing the oxidation-reduction potential (-408 mv) and lag phase reduced to 8.48h from 14.71h in binary system, a 53.73% performance boost. Maximum Energy Conversion Efficiency of 8.1% was achieved in experimental group ternary-C2 of ternary system which is 12% and 52.83% better than binary system (7.2%) and control (5.3%). The ternary system provides a better hydrogen production metabolite route and reduces VFA’s accumulation.