Nature inspired artificial photosynthesis technologies for hydrogen production: Barriers and challenges

Hydrogen drives the big wheel of nature. Hydrogen nuclear fusion in the sun produces light and heat. Solar flux reaching the earth's surface in an hour is far more than global annual energy demand. Photosynthesis traps 100-TW solar energy annually into biomass on land at 0.1% efficiency that is about six times more than global yearly energy demand. All photosynthetic organisms (photoautotroph) annually convert 100-billion tons of carbon in the atmosphere into biomass. The rampant rise in energy demand requires to replicate natural photosynthesis process artificially to convert solar energy and Carbon dioxide (CO2) in liquid and burnable gaseous fuels. Chemists, physicists and biologists are collaborating to develop suitable catalysts for artificial photosynthesis. There is a consensus the sun can fuel transport sector by hydrogen and power grid by photo-electricity. It is well in time to develop a full spectrum of solar technologies instead of keeping ourselves plugged to hydrocarbon honey. Photocathodes and catalysts can mediate water splitting using nature-inspired artificial photosynthesis. Economic hydrogen production can accomplish the grand energy transition from fossil fuels to sustainable and renewable energy sources. This paper reviews the recent advances in artificial photosynthesis technologies and presents our work on the microbial fuel cell for hydrogen production and points out technical barriers and operational challenges.