Hydrazine as a facile and highly efficient hydrogen source for reduction of NaHCO3 into formic acid over Ni and ZnO catalysts

• Highly efficient reduction of NaHCO3 into formic acid was achieved.
• Common Ni and ZnO powders were employed as co-catalysts.
• In-situ hydrogen from N2H4·H2O possessed high activity for NaHCO3 hydrogenation.
• A considerable high formic acid yield of 62% with 99% selectivity was obtained.

Conversion of CO2 into value-added chemicals has attracted considerable attention as an important method to reduce greenhouse gas emissions and also to alleviate the current dependence on fossil fuels. Traditional reducing agent for CO2 reduction relies heavily on gaseous hydrogen from high-pressure cylinder, which meets storage and transportation problem. Moreover, the elaborately prepared and noble-metal involved catalysts are required commonly. Thus, new safe and facile hydrogen source is needed urgently. Hydrous hydrazine, which possesses high hydrogen capacity (7.9%), is regarded as a promising liquid hydrogen storage material. Herein, hydrous hydrazine was employed as an in-situ hydrogen source which possesses high reactive activity for reduction of CO2 under hydrothermal conditions. A 62% yield of formic acid with 99% selectivity was achieved by using a common Ni and ZnO powder catalyst. The proposed method is facile and safe because it requires neither elaborately prepared catalysts, nor high-purity hydrogen and hydrogen storage.