Defect engineering has recently emerged as a cutting-edge discipline for precise modulation of electronic structures in nanomaterials, shifting the paradigm in nanoscience from passive ‘inherent defect tolerance’ to proactive ‘defect-controlled design’. The deliberate introduction of defect—including vacancies, dopants, and interfaces—breaks the rigid symmetry of crystalline lattices, enabling new pathways for optimizing catalysis performance. This review systematically summarizes the mechanisms underlying defect-mediated electronic structure at active sites regulation, including (1) reconstruction of the electronic density of states, (2) tuning of coordination microenvironments, (3) charge transfer and localization effects, (4) spin-state and magnetic coupling modulation, and (5) dynamic defect and interface engineering. These mechanisms elucidate how defect-induced electronic restructuring governs catalytic activity and selectivity. We further assess advanced characterization techniques and computational methodologies for probing defects-induced electronic states, offering deeper mechanistic insights at atomic scales. Finally, we highlight recent breakthroughs in defect-engineered nanomaterials for catalytic applications, including hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and beyond, while discussing existing challenges in scalability, defect stability, and structure–property causality. This review aims to provide actionable principles for the rational design of defects to tailor electronic structures toward next-generation energy technologies.

The unique structural configuration of amorphous nanomaterials, characterized by their disordered atomic arrangements, highly exposed active sites, and isotropic homogeneity, enables exceptional catalytic performance that bridges the gap between homogeneous and heterogeneous catalysis. In this work, an amorphous CuPd catalyst was fabricated through incorporating Cu ions into the disordered Pd lattice, creating an amorphous monolayer architecture with engineered hydrogen transport pathways. The precisely modulated atomic/electronic configuration optimizes the adsorption configuration and bonding strength between substrate/intermediates and catalysts surfaces. The amorphous catalyst achieves 96.2% selectivity at 99.1% conversion under mild conditions, with a time of flight of 6004 hour ⁻¹ . These results demonstrate that amorphous architectures, with their disordered atomic arrangements, uniformly distributed active sites, and tunable adsorption energetics, establish a generalized design framework for high-performance catalysts, achieving superior selectivity and activity compared to crystalline systems.

Stiffness-damping balance, high specific mechanical performance, and corrosion resistance are demanded for metals. Here, we developed an enamel-inspired ceramic (EIC) coating strategy involving hydrothermal growth of a tooth enamel-like ZrO₂ nanorods on Zr foil and amorphous ZrO₂ intergranular phase formation via controlled hydrolysis. The EIC coated Zr foil (Zr-EIC) achieved a high viscoelastic figure of merit (4.6 GPa); as well as excellent specific stiffness and hardness owing to the lightweight of ceramics, surpassing the values of Zr and previously reported Zr-based alloys or Zr-based composites. This was due to the vertically oriented stiff nanorods and unique energy dissipation derived from deformation at the crystalline/amorphous interfaces. It demonstrated exceptional NaCl corrosion resistance. This approach showed universality across Ti, Zn, and Cu substrates, enhancing both mechanical properties and corrosion resistance. By constructing an enamel-like hierarchical structure on the metal surface, the strategy overcomes traditional metal limitations without causing an increase in density.