Introduction

This chapter focuses on five representative categories of iron-group metal compound nanomaterials with extensive research and practical value: hydroxides, sulfides and phosphides, carbides and nitrides, high-entropy compounds, and coordination compounds. It also focuses on the practical significance and application value of these nanomaterials in three key fields: energy, environment, and catalysis. The chapter synthesizes the detailed explorations of their roles in optimizing energy conversion efficiency, enhancing environmental remediation efficacy, and boosting catalytic activity/selectivity. Iron-group metal compound nanomaterials have rich active sites, tunable electronic structures, and excellent redox performance, giving them significant applications in heterogeneous catalysis, electrocatalysis, photocatalysis, and other fields, and making them a research hotspot in the catalytic field. The main research motivations and development directions are structural design and performance optimization, development of green large-scale preparation technology, and improvement of adaptability to actual working conditions and application expansion.