Page 97 - AWSAR 2.0

the continuous production of usable energy (preferably electricity) from solar irradiation is an impractical proposition. Here, we look into nature for inspiration. The driving force behind all the biological processes is solar energy, even if it is not entirely apparent at first. Biology traps the solar energy into chemical bonds via photosynthesis, by which plants prepare their food. In this process,
green leaves capture sunlight
and use it to convert water,
carbon dioxide and minerals
into oxygen and energy-rich
compounds. We thought of
taking a leaf out of this natural
energy conversion blueprint
and imitate this process.
However, we have simplified
the full process into two steps:
(i) harvest solar energy and, (ii)
transform that absorbed solar
energy into H-H chemical bond
via hydrogen (H2) evolution + reaction (HER). The simplicity of proton (H ) into H2 conversion is not the only reason behind selecting this reaction for proper solar energy storage. The high energy density of H2 molecule and efficient extraction of the stored energy via fuel cell also established H2 as one of the most prominent energy vectors in the
Preparation of an artificial blue leaf:
Dr Gayatribahen Joshi || 73
field. With all this background, now we are set to develop an artificial leaf that will effectively capture solar energy to H2.
Therefore, how are we going to make this artificial leaf? Thinking about leaves, we need to select a light collector, which can absorb sunlight and create electricity. And, the materials (catalyst), which can pull this
electricity and convert one of the most common sources of the proton, water molecule, into hydrogen and oxygen. The following are the key challenges we face during the development of this artificial
leaf: (i) The inefficiency of the device due to the lack of effective light absorption,
(ii) Long-term durability under solar irradiation and
(iii) The overall cost of the system.
Hence, developing a robust, affordable, efficient and tunable artificial photosynthetic device is our principal goal. The research outcome of this project has the potential to lay the cornerstone for developing the next generation of renewable energy infrastructure.
The burning of these fossil fuels generates an excessive amount of CO2 that inadvertently affects our climate. Thus, we are standing on a critical juncture, where we need a continuous source of energy to continue the societal growth, preferably with minimal side-effects on the environment.
(ACS Energy Letters, 2019, 4, 2428–2435)