Unfolding essence of nanoscience for improved water splitting hydrogen generation in the light of newly emergent nanocatalysts

To meet the escalated global energy requirements while preserving the intrinsic environmental integrity, it is highly important to develop renewable and clean energy sources as the replacement of traditional fossil fuels. Hydrogen is an appealing green energy source due to huge energy density, carbon free by products, renewable and storable nature. Water splitting is an exceedingly important technology for sustainable hydrogen generation. However, the process needs high-performance, stable, and low-cost catalyst for efficient hydrogen evolution reaction (HER). This review article aims to summarize the theoretical understanding of foundations for various H 2 development technologies along with their merits and de-merits. The essence of nanosciences for the development of nanoengineered stable and cost-effective catalysts has been comprehensively showcased by enlightening the outstanding performance of newly emergent nanocatalyst for H 2 production via water splitting. Particular consideration has been devoted to prevalent approaches that can improve the catalytic properties of the categorized nanocatalyst and provide insight towards atomic assembly related mechanism. Future consideration for catalytic enhancement is also discussed. In short, this critical review comes up with the insight essence of hybridized catalyst that are noteworthy for researchers and industrialists to sort out the best class of materials in accordance with hydrogen production techniques. • Underlying mechanisms for Hydrogen production via existing water splitting techniques have been summarized. • Describes the fundamental insight of material requirements as water splitting catalyst. • Unveils the pros and cons of traditional Nanocatalyst. • Introduce features of emerging MXenes, Nano Encapsulated, Nanocurved, Janus Nanoparticles, and Single Atomic Catalyst. • The new pathways are highlighted to overcome the most encountered challenges in water splitting hydrogen generation.