Sorry for the late post this week! Starting off Crescenta Valley made another plate using just 0.1 M BiVO4 and another using 0.1 M BiVO4 layered with 0.05 M Co, and BiVO4 layered with .05 M Ni and .05 M Fe in a 1:1 ratio. They want to test the effects of Co on BiVO4 compared to Ni:Fe. They also made a solution of 0.05 M Fe(NO3)3 using ethyl alcohol instead of water. Their mentor suggested that this might help with the coffee ring effect; they will spot two solutions, one with water and one with ethyl alcohol, and see if the coffee ring effect is diminished.
Beckman HS’s Group 1 researched to find future work: band gaps of different metals. They also UV treated a new plate of 0.04 Iron (III) Nitrate because they had positive results last time they tested it. They wish to continue to test the effect of UV treatment and find optimal metal oxides/specific molarities that work well with UV treatment. Group 2 tested a UV treated plate with ratio of Nickel, Iron, Aluminum (1:3:1; 0.03:0.09:0.03). They are planning to compare with a non-UV treated plate (same ratio). Since Nickel is a less than optimal photoanode, they researched other metals and decided to replace Nickel with Copper next time. Group 3 finished spotting the layered plate they started last week (0.04M Cobalt(II) Nitrate over 0.04M Iron(III) Nitrate) by adding the Cobalt Nitrate layer on top. They fired the mixture plate (mixture of 0.04M Cobalt Nitrate and 0.04M Iron Nitrate). Their goal is to compare the methods of mixing two metals and layering them because there were various groups at CCI with positive results that used the layering method. They re-tested the Cu-Ni-Fe plate because of dark current issues they had last time they ran it. Group 4 epoxied 0.03M Copper (II) Nitrate plate and ran it. Group 1 tested 0.04 Copper (II) Nitrate in the past, so they will be comparing the results with each other and determine which molarity works best with Copper.
San Marino Red team decided to use Ni(NO3)2, MnCl2, and CuSO4 to test these materials for flaking and/or corrosion. They found very little flaking—a good sign! Their hypothesis for this finding is that the absence of significant flaking was due to the low concentration of the spot solutions (only 0.05 M) and leaving it on the hot plate for an 30 extra minutes. The photoactivity of the spots was not as high probably because the plate was not baked and that the spot solutions had a lower concentration than usual. The spots changed color as the plate was being tested (as the current was flowing)—–Not a good sign! This could mean corrosion or (a) chemical reaction(s) may be occurring. For next week’s meeting, they plan on testing this same plate after it is baked in the kiln.
The San Marino Wand team decided to continue with the hypothesis that a good catalyst would be a good light absorber. However, this time, knowing to focus on oxygen evolution, they looked towards compounds such as BaNiO3 and Ni2Se3 and NiFeO, and NiMO on the OER side. On the light absorber side, Silicon. They ended up plating: Cu, Co, Iron, and Nickel, on a base of ammonium vanadate. Testing the plate they found nickel worked best so they made a new plate with just ammonium vanadate and different ratios of nickel.
Mayfield’s PEAK team retested the plate of FeCoZn from last week with new wire epoxied in a different corner. While this did decrease activity of the very active spot next to the old wire, the spot was still quite active compared to the rest of the plate. Their next experiment is to test efficiency of multiple layers compared to a single layer so they made plates 21 (FeZn with multiple layers) and 22 (CoZn with multiple layers). Team SEA got marginal results from a 4:7 ratio of their colored to non-colored metals. Retesting the old plate didn’t yield good results, but remaking the materials the result was reproducible. They will be looking at 1:8 and 5:8 ratios next. Team RAM has disappointing results from their Bismuth, Vanadium, and Tungsten and Bismuth, Vanadium, and Nickel plates. Perhaps a new solution of vanadium will help. If any other teams have tips for using ammonium metavanadate since it is not very soluble, please comment!
Concordia attempted three different tests. First, tried to test CONa3 which was bismuth nitrate and ammonium vanadate with the concentration ratio ranging from 1:1 to 1:1.7, the higher being bismuth nitrate. Unfortunately the epoxy fell out when they put it in the sodium sulfite electrolyte solution because it wasn’t dry yet. Second, they used the tesla coil gun and shocked the CON8 plate for testing for next week. The spots changed from a yellow to a reddish brown color. Third, they tried to do our own UV/Ozone treatment. However, due to the lack of appropriate materials in the lab, they were unable to do the testing. They will be using the set-up at Beckman HS next week.
Finally Franklin team 4 is testing some new materials- Ni Cr Y W. The spots were spreading quite a bit, and even adding glycerol didn’t solve the issue. They made two plates with these materials and fired them both to test with the HARPOON kit next time. Team 5 was having trouble seeing any oxygen produced when testing their plate with HARPOON, even at a higher voltage. They plan to add 10% glycerol to their spots next time to see if that will help.
Thanks for all the great updates everyone!