Facile one-pot synthesis of functional hydrochar catalyst for biomass valorization

Corn stover derived hydrochar (HC) doped with aluminum nanoparticles was synthesized through the facile one-pot hydrothermal carbonization for glucose to fructose isomerization. Amorphous aluminum nanoparticles with crystalline size less than 0.5 nm were uniformly loaded on hydrochar. The phase of the Al-oxide nanoparticles was tailored through aerobic/anaerobic calcination. The results showed that the amorphous aluminum nanocrystals with six coordinated Al-oxide structure were formed under oxygen calcination, which facilitated the high catalytic activity and selectivity of glucose isomerization. It was found that catalysts prepared at hydrothermal temperature of 180℃ and further calcinated at 300℃ under aerobic condition (Al/HC 180 -300/O) achieved a fructose yield of 42.6% and a selectivity of 83.6% at 180 °C for 5 min. The kinetics, catalytic mechanism, and the deactivation mechanism of the glucose to fructose were further studied using Al/HC 180 -300/O catalyst. This study provides a high energy efficiency and low metal loading carbon-based catalysts synthetic approach applicable for biorefinery.