Catalysts accelerate chemical reactions, but the widely used metal platinum is scarce and expensive. A team of Dutch scientists have found that using hollow nanocages of an alloy of nickel and platinum as a catalyst results in a 20-fold increase in the activity of both solutions in a hydrogen-based fuel cell electrolyzer. Researchers want to use this new catalyst to develop a refrigerator-size electrolyzer of about 10 megawatts in the future.