In a typical process, NiCl2*6H2O (0.173 g) and p-benzenedicarboxylic acid (PTA) (0.332 g) were dissolved in 10 mL and 5 mL N,N-dimethylformamide (DMF), respectively under vigorous stirring for 20 min at room temperature. Subsequently, the DMF solution of NiCl2*6H2O was slowly added to the ligand solution (PTA) drop by drop. After forming a greenish solution, the as-prepared mixture was transferred into a Teflon-lined stainless steel autoclave (50 mL volume) and maintained at 120 degC for 16 h. After the autoclave cooled down to room temperature, the precipitate was washed via centrifugation at 10000 rpm for 5 min with DMF and alcohol several times followed by solvent exchange with methanol four times over two days. The samples were fully activated by removing solvent with vacuum at 100 degC over 12 h.

NiCl2*6H2O
dissolved
0.173 g
g
p-benzenedicarboxylic acid (PTA)
dissolved
0.332 g
g
N,N-dimethylformamide (DMF)
10 mL
mL
N,N-dimethylformamide (DMF)
5 mL
mL
NiCl2*6H2O (0.173 g) and p-benzenedicarboxylic acid (PTA) (0.332 g)
dissolved
20 min
min
as-prepared mixture
maintained
120 degC
degC
as-prepared mixture
maintained
16 h
h
Teflon-lined stainless steel autoclave
volume
50 mL
mL
precipitate
centrifugation
10000 rpm
rpm
precipitate
centrifugation
5 min
min
samples
fully activated by removing solvent with vacuum
100 degC
degC
samples
removing solvent with vacuum
12 h
h