Natural lignin as efficient catalyst for H2 production from NaBH4 methanolysis at low temperature

Abstract

Herein, natural lignin is used for the first time as a catalyst for the methanolysis of NaBH4. Lignin exhibits excellent catalytic activity for the methanolysis of NaBH4, and the HGR value is as high as 20425 mL H2·gcat−1·min−1 at room-temperature. It is still satisfactory even at − 20 ℃, with a HGR of 2182 mL H2·gcat−1·min−1, which is the highest value reported in the literature to date. In addition, the study of kinetic reaction orders for NaBH4 methanolysis catalyzed by lignin indicates that the catalytic methanolysis of NaBH4 obeys first-order kinetics with respect to both of NaBH4 concentration and catalyst dosage. The activation energy for the methanolysis catalysis by lignin is calculated to be 19.5 kJ·mol−1 at low temperature of − 20 ∼ 25 ℃. The lignin retain over 66% of the original catalytic activity at the end of fifth consecutive reuse, and the catalytic activity can be completely recovered through simple acid treatment.