This (pressurised electrolysis) would be a new field. A couple of things come to mind, most particularly that many chemical and (potentially) electro-chemical redox reactions change completely when you go over 100C. So you might have to create a new fuel system and use novel electrolytes to avoid the unexpected.
With the recent pathetic demonstration of Rossi creating more controversy about the feasibility of cold fusion, a re-think of the direction of the LENR movement is needed to make a crucial breakthrough. After 30 years of trying to get a low energy fusion device, Rossi seems to have come closest, but with lots of smoke and mirrors and associated disbelief.
As a newcomer to the LENR forum, I see a lot of re-iteration of theories and promising ideas that are fairly circular without leading anywhere: hence this stream titled 'What should we do next ?'.
I think that Takaaki Matsumoto stated that he only made advances when he became less focused upon the calorimetry side of his experiments. Perhaps, as suggested by Alan Smith, a look at higher temperature and pressure experiments would seem to be a good thing and, with significantly lower levels of neutron production, they won’t resemble pressurized water fission reactors in terms of nasty side effects (neutrons) and thus energy production cost.
The term 'pressurised electolysis' might be a bit restrictive: perhaps Low Temperature and Pressure (LTP) would be more inclusive.
To me as a newbie, there seems to be an unmistakable obsession with the fusion aspect of LENR, when the by-product elements of Takaaki Matsumoto’s experiments could well be fission related. I would suggest that the possibility of low temperature fission be given more attention within LENR.
With large unstable atoms, fission nuclear chain reactions would seem to be triggered and maintained by neutrons. Could not similar nuclear chain reactions triggered by electrons and/or ball lightning occur for far smaller, more stable elements such as potassium, iron, palladium and copper to produce fission products with minimal neutron production. The possibility of LTP fission and fusion reactions should be on the board at all times until one such interpretation leads to the desired low cost, low neutron LENR power generation.
And unless the LENR group can find the required answers, nobody will in the near future.