The article discusses the pressing need for innovative solutions to meet the growing energy demand while combatting climate change by reducing CO2 and CH4 emissions. Hydrogen is highlighted as a clean and sustainable energy source with high energy content and environmentally friendly by-products, making it essential for a green economy. The focus shifts to photocatalytic overall water splitting (POWS) as a method to convert sunlight into clean energy, leading to hydrogen production while reducing greenhouse gas emissions. Despite challenges in efficiency, research is ongoing to develop photocatalytic systems capable of large-scale industrial hydrogen production. The article also emphasizes the importance of gas-sensing technologies in environmental monitoring and security, highlighting the need for advanced materials with improved sensitivity and selectivity. Nanoscale carbonaceous materials like graphene and carbon nitride are explored for their potential in photocatalysis and gas sensing, with recent discoveries of new carbon isomers opening doors for nanoelectronics and catalysis. The synthesis of novel carbon structures like biphenylene (BPN) shows promise for applications in nanoelectronics and gas sensing, with potential as a metal-free catalyst. Overall, the article paints a positive outlook on the advancements in hydrogen energy and nanomaterials for a sustainable future.