A Novel Dual-Rotor Spinning Disc Reactor for Process Intensification of Glycerol-Assisted Hydrogen Production

Abstract

This study presents the first integration of a novel dual-rotor spinning disc reactor (DR-SDR) with the paired glycerol electrochemical oxidation reaction and hydrogen evolution reaction (GEOR-HER) electrolysis. The work demonstrates both a fundamental investigation of mass transfer behavior in the DR-SDR and its practical implementation under challenging electrochemical conditions. The mass transfer behavior was quantitatively evaluated using the limiting current density method. The mass transfer coefficient under the combined action of hub inflow and disc rotation exceeded the sum of the coefficients measured under each condition individually, confirming a synergistic enhancement. An overall mass transfer coefficient of 8.92 × 10-5m s-1was achieved, accompanied by a diffusion layer thickness as low as 7.18 μm. Such intensified transport conditions are particularly relevant for gas-evolving systems, where surface-attached and dispersed bubbles limit electrolysis efficiency. These challenges are further exacerbated in the paired GEOR-HER electrolysis, where gas evolution coincides with a highly viscous electrolyte. To address these combined limitations, the DR-SDR was subsequently applied to the paired GEOR-HER electrolysis. The introduction of disc rotation effectively mitigated both hydrogen bubble accumulation and viscous electrolyte transport challenges, resulting in a stable operational current density of 832.4 mA cm-2at 2.4 V and enabling the coproduction of value-added organic acids, which is not achieved in conventional alkaline water electrolysis. These results establish an integrated strategy that couples process intensification and organic-assisted electrolysis to concurrently enable green hydrogen production, membraneless operation, and anodic valorization of waste-derived organic feedstocks, even under challenging conditions.