Sciencemadness Discussion Board

Photodissociation of water on Ag3PO4

FragranceLover89 - 29-10-2020 at 19:48

I wanted to photo dissociate some water so I bought some AgNO3 and H3PO4 (85%) and made Ag3PO4 through the salt replacement reaction with sodium bicarbonate.

The product was a yellow green powder, which initially did not produce gas bubbles upon illumination with a bright lamp. It was only the next day that I noticed a steady stream of oxygen bubbles coming from the powder when the jar was illuminated from the bottom.

My next plan is to add a redox agent like methylene blue to oxidize the carrier from Ag3PO4 preventing it's reduction and dissociation. Ag3PO4 produces only a water splitting half reaction so the pH likely drops as more protons are put into solution. I noticed Ag3PO4 (under liquid) degraded after a few days in darkness making me question the stability of the molecule. Another alternative to increase stability is to mix Ag3PO4 with a hydrogen evolving photo-catalyst like TiO2.

Bedlasky - 30-10-2020 at 03:30

That's really interesting, I never read about this property of Ag3PO4. I'll definitely try it.