CO-free hydrogen production from decomposition of formic acid over Au/Al₂O₃ catalysts doped with potassium ions

Doping of a 2.5 wt.% Au/Al₂O₃catalyst with potassium ions (3 wt.%) leads to a significantly increased rate by > 1 order of magnitude of decomposition of formic acid at 358 K as compared to an undoped catalyst with the same mean Au particle size (2.6 nm). The doped catalyst gave stable and CO-free (< 10 ppm CO) hydrogen production. The mechanism of the reaction changed. This was provided by a significantly increased content of a reaction intermediate – formate ions (HCOO⁻) controlled by K⁺counterions in formic acid condensed in the pores of the catalyst.