Thermal H2 Production by Decomposition of HCOOH with Pd/ZnO Catalyst

Abstract

We present high-yield hydrogen production through selective thermal decomposition of formic acid with Pd/ZnO catalyst. This work analyzed the paths for HCOOH dehydrogenation to CO2 + H2 and dehydration to CO + H2O through the carboxyl (COOH) and formate (HCOO) intermediates. The results showed that metallic Pd is highly dispersed on ZnO surface. ZnO reacted with Metallic Pd. Then, this reaction generated PdZn alloy. Existence of PdZn alloy was confirmed by X-ray photoelectron spectroscopy (XPS). PdZn alloy catalyst may produce carbon dioxide (CO2) selectively. However, the hydrogen production decreased with progress of time. The results may be owing to it that PdZn alloy changed into PdO. By using only 50 mg of the Pd/ZnO containing the 0.1wt.% Pd, we could achieve an optimal H2 generation rate of 220 mol h−1. Therefore H2 and CO2 generation may occur mainly through formic acid decomposition.