Waste-Recovered Nanomaterials for Emerging Electrocatalytic Applications

Energy is essential and affects all aspects of our society, including the economy and modern living. However, the unparalleled rise in the global population, technological advancements, and changes in the scope of energy resources are all affecting the present energy landscape. With the increasing demands for energy and over-consumption of fossil energy, CO₂ emission is anticipated to rise over the next decades with devastating consequences on the environment and humans’ lives. To avoid future eventualities, clean energy technologies have evolved with the expectation to diversify the global energy resources. Alternative energies are likely to show a crucial role in meeting not just the future energy needs but to remedy the escalating negative impact of fossil energy. Various clean energy systems, including fuel cells, electrolytic cells, rechargeable batteries, solar cells, etc., have emerged as viable renewable energy systems with even a wider range of applications and less impact on the environment. The efficiency of these energy systems is critical but is dependent on several technical factors, including electrochemical hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR). An efficient electrocatalyst is required to drive the kinetics of these electrochemical processes effectively. However, developing practically efficient electrocatalyst is a significant challenge in terms of striking a balance between cost, performance, and sustainability of the active materials. Irrespective of any challenges, developing cost-effective and efficient electrode materials is vital for large-scale implementations of these energy systems. This chapter discusses the alternatives, recent progress, and future trends of using various waste materials for the development of advanced electrodes for various electrochemical systems.