A large scale hydrogen generator driven by purely sunlight was demonstrated by Prof Domen’s group. The results were published by Nature on 25 August 2021.

The study used a SrTiO2:Al photocatalyst and reached an efficiency of 0.76% for Solar-to-Hydrogen process (STH). The STH would be 5-10% for any economically viable application. Lifetime of photocatalyst is another constraint to the commercialization.

Please consider the following questions and describe your solutions.

Question 1: Please identify the routes to increase STH, as many as you can.

Question 2: Please explain the related mechanism for each of the high STH route you identified.