**1. Introduction**

The new and advanced materials such as high entropy materials, metal hydrides and MOFs enables the realization of renewable energy technology (i.e. Fuel cell, zinc-air batteries, green hydrogen technology, oxygen reduction) [1]. The high entropy alloy's (HEA's) unique structural and morphological characteristics, tuneable chemical composition and functional properties have attracted considerable interest in the field of renewable energy technology [1]. In order to develop environmentally sustainable energy sources, innovative methods for designing catalytic nanoparticles are required [2].

Fuel cells and hydrogen generation have gained substantial attention as an alternative to conventional energy conversion technologies to overcome the consequences that arise with the utilization of fossil fuels. These issues are in connection with the depletion of fossil fuel reserves, demand for carbon-neutral energy sources, climatic changes concerns and economic consideration. Furthermore, energy storage has become the research of interest for renewable energy sources such as metal-organic frameworks, and metal hydride to store hydrogen and batteries materials.

This chapter presents the emerging materials (i.e. high entropy, metal hydride), their counterparts (i.e. binary and ternary PGMs and PMGs-MOFs) and the application of these materials for energy storage and conversion. The synthetic/fabrication approach of high entropy alloys (HEAs) and the computational (i.e. machine learning and density functional theory) approach for energy storage and conversion catalyst screening process are discussed. In addition, the intrinsic properties, geometric properties, and challenges associated with electrocatalysts in energy conversion, current status, conclusions, and future perspective are also fully elucidated.
