Electron transfer in catalysis: from fundamentals to strategies

The essence of catalysis lies in the transfer of electrons, driving the cleavage and formation of chemical bonds. Understanding the fundamental attributes of electrons is essential for improving the efficiency of catalytic processes. This tutorial review provides a systematic and accessible framework, integrating electron fundamentals and dynamics across diverse catalytic scenarios. We begin by summarizing the foundational principles of electron behavior, including free electrons, molecular orbital theory for molecular systems, and crystal field splitting theory in catalyst materials. Next, we elucidate the basic principles governing key catalytic processes: the Arrhenius equation in thermocatalysis, band structure theory and electron-hole recombination in photocatalysis, electronic structures of active sites and adsorption mechanisms in electrocatalysis, and the piezoelectric effect in mechanocatalysis. Building on this foundation, a universal framework for understanding electron transfer dynamics across surfaces and within bulk materials is proposed. Subsequently, we examine current material engineering strategies, categorizing them based on the fundamental parameters, including charge, orbital, lattice, and spin. Finally, we highlight emerging opportunities, with a particular focus on the underexplored potential of electron spin and the integration of interdisciplinary approaches for advancing energy technologies. By presenting a clear physical perspective and an organized knowledge base, this work is expected to bridge the gap between fundamental physics and chemical reactions, fostering interdisciplinary collaboration and driving innovations in energy solutions.