This book presents recent advances in the development and application of innovative materials for sustainable energy and environmental solutions. It explores the synthesis, characterization, and performance of nanomaterials, semiconductors, and functional composites in technologies such as solar cells, microbial fuel cells, and photocatalytic systems. Special attention is given to environmentally focused applications, including biomass conversion, pyrite beneficiation, and antimicrobial coatings. By bridging materials science with energy and environmental engineering, the book offers researchers and practitioners valuable insights into emerging strategies for clean energy generation and ecological remediation.