Which catalyst could produce more UDH than another? That depends on what the catalyst does. Which depends on what entropy leads to (hydino like condensed states or pseudo-neutrons). If one favors energy must be added to a proton/electron state to generate a neutron like state, then the catalyst plays the classic role of helping reduce an energy barrier. The catalyst gives energy to UDH which then causes fusion of UDH with itself or similar states of other atoms. Then energy from fusion is taken back to the catalyst and stored in the catalyst. Which then provides the energy for the catalyst to catalyst the production of more UDH. The production of the first excited catalyst comes by absorption of random high energy radiation or through a phat mechanism via energy supplied via electricity or a laser. The first fusion event is auto-catalytic for catalyst. It makes more energized catalysts at the expense of energy not released as heat during the fusion reaction. The energy storage mechanism is explained by Paul Brown in "Neutralizing nuclear waste using applied physics".
A quote from that article as follows:
Hydrogen can't store the energy necessary to overcome the barrier to fusion. It has too low of A. But multiple hydrogen can contribute that energy to an atom with a larger A that can store it and use it to cause fusion catalysis.
Oxygen not some metal can obtain the highest potential to catalyze fusion.
