http://www.sciencemag.org/news/2016/07/our-last-common-ancestor-inhaled-hydrogen-underwater-volcanoes?utm_campaign=news_daily_2016-07-26&et_rid=16756882&et_cid=665580
This explains why Nadph and NADH are so important for life.
Thus basically you can rule out worlds where the dynamics quickly eliminates hydrogen from the surface.