There's no systematic evidence at this point as far as I can tell that removing impurities from the surface of a substrate does anything beneficial. It seems to simply be an assumption that this is the case. It might be the opposite: that preparing a substrate by cleaning it will be partly or wholly detrimental.
Related to that i copied this from Peter's EGO-OUT blogs Comments section at 2017-02-20:
"Alan DeAngelis Andreas Moraitis
a day ago
I was thinking about tetrahedral and octahedral nickel hydride complexes a few years ago on E-cat site. https://ecatsite.wordpress.com...
“ Ni(0) (metal) + 6 H2 (gas) > [NiH6]6- + 6 H+ (protons)
If I have this right, a set of six empty sp3d2 hybrid orbitals can be formed
on the nickel by mixing 4s, 4p and 4d orbitals and then the lone pairs of
electrons of the hydrides could fill them to form the octahedral complex
“Ni(0) (metal) + 4 H2 (gas) > [NiH4]4- + 4 H+ (protons)
Could also have a set of four empty sp3 hybrid orbitals form on the nickel and then the lone pairs of electrons of the hydrides could fill them to form the tetrahedral complex [NiH4]4-.”
Another thread here also suggested that NiO instead of very pure Ni would be useful material for LENR. (I suppose no-one of the members of this forum did try this ever but ...):
"LENR as entertainment
Jul 10th 2015
The experiment was to check the stability of nickelous oxide paint in hydrogen at 1000 C. I was asked by management to verify that the material would maintain color as a ceramic paint. My Variac/transformer would just meet this requirement. At 830 C. thermal run away occurred and the tube housing the alumina FiberFrax/NiO melted. I now realize that what had occurred was simply hydrogen fusion. Gas chromatography indicated a small increase in helium after flow through the operating reactor.
After 50 years this fusion it's still inconclusive because of the focus on nickel with various impurity levels leading to trial and error results. Instead nickelous oxide suspension on alumina fiberfrax will give very good repeat ability. The NiO particles must be submicron in size.
All my posts are on this forum."