Since the first report on solar fuels production by Fujishima and Honda in 1972, photoelectrochemical/electrochemical production of fuels, such as H2, carbonhydrates, etc., has significantly advanced over the past few decades with the remarkable development in new catalytic materials, fundamental knowledge, and new applications. In particular, the efficiency for solar fuels production steadily increases, for example, solar H2 production efficiency has reached 1.1% in term of the solar-to-hydrogen energy conversion efficiency. These progresses render solar fuels as promising candidates for use...