Sustainable regeneration of deactivated hydrochar-supported Ni catalyst for enhancing low-temperature tar reforming performance

Abstract

Catalytic tar reforming using biochar-supported nanoparticle catalyst has emerged as a prominent approach for efficient biomass gasification. However, the widespread issue of catalyst deactivation significantly impedes their industrial application. Recent studies have successfully elucidated the deactivation and regeneration behaviors of pyrochar-based catalysts during high temperature (700–900 °C) tar reforming. In contrast, the deactivation and regeneration mechanisms of hydrochar-based catalysts for low temperature (e.g., 600 °C) biomass tar reforming remain unclear. In this study, we report a simple and cost-effective approach for the regeneration deactivated hydrochar-supported nickel catalyst (Ni_0.1/HC). A straightforward N₂ regeneration treatment (800 °C, 30 mL/min for 30 min) restored the Ni_0.1/HC catalyst to its highest tar reforming efficiency (71 %), H₂ selectivity (38 %), H₂ yield (758 mL/g) and highest LHV_g (8.59 MJ/Nm³). We attribute this promising regeneration performance, which significantly outperforms previously reported regeneration atmospheres (such as CO₂, O_2, and air), to the suppression of Ni sintering that achieved by limiting oxidation of the coke/hydrochar support. This work advances our understanding of the deactivation and regeneration mechanisms of the hydrochar-based tar reforming catalysts and could facilitate the practical application of biochar-supported catalysts in biomass conversion.