A nickel-beryllium alloy could be an interesting and available catalyst for use in Mills-Holmlid dense hydrogen research. It would be an active material in several ways - used as the target for a high pressure flow of hydrogen. The 360 alloy is mostly nickel with a few % beryllium and some titanium. https://materion.com/products/high-performance-alloys/nickel-beryllium-alloy-360 AFAIK no experimenter has used this alloy in LENR before now. Researchers often avoid beryllium, and for good reason.
The premise, or working hypothesis for suggested experiments would be that a "halo nucleus" serves a critical function in the completed reaction ... which is first based on nickel and titanium as the 'shrinkage' catalysts forming dense hydrogen eventually into what can be called theĀ 'pseudo neutron' (activated dense hydrogen). In this reaction, beryllium uniquely provides an accumulation stage - due entirely to the extended lifetime of the nuclear halo, which is unique. Google: halo nucleus. Beryllium seems to be the only atom in nature which has a long-lived halo nucleus feature. More on the details of this (unproved) halo nucleus hypothesis later. Anyway, let's hypothesize for now that a pseudo-neutron or even real neutrin forms in a halo nucleus if there is enough time for it to react with the Universal neutrino flux. Halo lifetime is the detail which demands beryllium, despite all its negatives (toxicity). In short, the dense hydrogen of Holmlid, captured into the halo by an atom of beryllium, eventually can form a neutron due to interaction with natural neutrino flux. This reaction is anti-entropic with probability based on residence time in the background flux. Thus, beryllium could be the magic element which optimizes the conversion of dense hydrogen into thermal energy (possibly via boron-8 instability). It would only works at all since beryllium has a unique long-lived and relatively stable halo-nucleus property.