The ink is composed 6 mg of catalyst (MOFs) dispersed in 0,7 ml H2O +0,3 ml C2H5OH+0,05 ml Nafion (5% wt).
I have tried different ratios of water:ethanol, but the same problem still exist.
I handly coat 1 cm2 of the nickel foil with 0,015 ml of ink and i have tried different amounts (0,005 / 0,01) and the same problem occurs.
Attached photo of coated nickel foil.
The sintering experiments could be performed by exposing the catalysts to a 1:1 mixture of steam and hydrogen at different temperatures at ambient pressure. Prior to sin- tering, the catalysts need to activated by reduction in H2 at 500 ◦C for 4 h. After sintering, the catalysts should passivated overnight at 50◦C in a mixture of 1% O2 in N2 before they taken out of the reactor.
Dear Abdullah,
Thanks for your kind reply. I think you did not get the point. Actually, what I am doing is drop-casting my catalyst ink at nickel foil surface to be used as an electrode for electrochemical water splitting reactions.
Hi Sayed,
You can try with water : alcohol (3 :1) and use 2-propanol instead of ethanol.
Slow evaporation also can help.
Regards,
Ayon
you may try to etch (increase the roughness) of your substrate before the casting
When it comes down to it, drop casting is a bad method for making working electrodes and slow drying even layer-by-layer isn't ideal (every layer anneals previous layers, especially with Nafion). Industrially spray-coating is the standard and a few people are experimenting with inkjet or slot-die casting, but for those the optimization needed is intense (porogens, dielectrics tuning, etc.).
Your best bet is to find a spray-coater or get a small hand-sprayer and spray onto a heated substrate (50-85 °C max if you're using Nafion). Try and cast your electrode in >40 scans that dry between coats.
If the Nickel doesn't adhere well even after roughing it up, you can spray onto PTFE and decal-transfer the electrode, although that's a last resort. You may also need to tune Nafion as a wt% of solids.
Dear All,
Thanks for your positive replies. I will try to apply your advises.
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