Synthesis of catalysts
Synthesis of Co1-SNC : 6 g melamine, 2 g
L-Cysteine and 10 mg Cobalt chloride were first grounded into a
homogeneous precursor by ZrO2 mortar ball. Subsequently,
the fine powder mixture was undergone a two-stage pyrolysis and
carbonization process at the Ar atmosphere (first stage: from 25°C to
580 °C, maintain at 580 °C for 2 h and then heated to 900 °C for 1.5 h).
The heating rate of the whole process was 2 °C/min. After cooling down
to room temperature, the product was leached at 80 °C in 0.5 M HCl for
24 h to remove the unstable species. Afterwards, the sample was heated
at 700 °C again to eliminate the residual Cl-.
Synthesis of Co1-NC : The same method was used
for the synthesis of Co1-NC (For Co1-NC,
L-alanine was used instead of L-Cysteine. For detail: 6 g melamine, 2 g
L-alanine and 10 mg Cobalt chloride was used).