Hydrogen Energy as Sustainable Energy Resource for Carbon-Neutrality Realization

For stepping toward a sustainable future, reducing carbon footprints by generation of a clean source of energy is a viable option that captivates researchers all around the globe. Hydrogen energy in the form of renewable energy resource has achieved sustainable status and is perceived as a feasible alternative of fossil derivative fuels ascribed to higher gravimetric density, which offers superior efficiency over conventional fuels. However, the nature of the H₂synthetic route is a determinant for clean energy production. Traditional gray H₂production generated via fossil fuels catalyzes global warming. Therefore, there is the need to develop environmentally benign methodologies such as green and blue H₂generation routes which are discussed in this review article by comparing distinct methods for the production of H₂with minimal carbon emission, along with their merits and demerits. We have precisely discussed the optimization of photocatalytic H₂evolution by optimizing the cost and catalytic system in terms of sustainability. Exploitation of cheap and noble metal free catalysts has been stressed for generating green H₂. The research domain of this article underlines the significance of green H₂production in attaining a carbon-neutral society with respect to H₂economy and its techno-economic analysis toward scalable applicability.